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SN74AXCH4T245
ZHCSJI7 – MARCH 2019
具有可配置电压转换、三态输出和总线保持输入的
SN74AXCH4T245 四位总线收发器
1 特性
•
1
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•
•
•
•
•
•
•
•
•
完全可配置的双电源轨设计可允许各个端口在
0.65V 至 3.6V 的电源电压范围内运行
总线保持数据输入消除了对外部上拉或下拉电阻器
的需求
工作温度范围 -40°C 至 +125°C
多向控制引脚，支持同步升降转换
无干扰电源定序
从 1.8V 转换到 3.3V 时，支持高达 380Mbps 的转
换速率
VCC 隔离特性
Ioff 支持局部断电模式运行
兼容 AVC 系列电平转换器
闩锁性能超过 100mA，符合 JESD 78 II 类规范
静电放电 (ESD) 保护性能超过 JESD 22 规范要求
– 8000V 人体放电模型
– 1000V 充电器件模型
有源总线保持电路会将未使用或未驱动的输入保持在有
效逻辑状态。不建议在总线保持电路上使用上拉或下拉
电阻器。如果 VCCA 或 VCCB 连上电源，则总线保持电
路分别在 A 或 B 输入端口上始终保持工作状态，与方
向控制或输出使能引脚的状态无关。
为了确保电平转换器 I/O 在加电或断电期间的高阻抗状
态，xOE 引脚应通过一个上拉电阻器连接至 VCCA。
该器件完全 适用于 使用 Ioff 电流的局部掉电应用。当
器件掉电时，Ioff 保护电路可确保不从输入/输出或偏置
到特定电压的组合 I/O 获取或向其提供多余电流。
VCC 隔离特性可确保当 VCCA 或 VCCB 低于 100mV
时，所有 I/O 端口均禁用其输出并进入高阻抗状态。
无干扰电源定序使电源轨能以任何顺序打开或关断，从
而提供强大的电源定序性能。
器件信息(1)
器件型号
2 应用
•
•
•
•
•
企业与通信
工业
个人电子产品
无线基础设施
楼宇自动化
SN74AXCH4T245 器件旨在实现数据总线间的异步通
信，根据方向控制输入（1DIR 和 2DIR）的逻辑电
平，将数据从 A 总线传输至 B 总线，或将数据从 B 总
线传输至 A 总线。输出使能输入（1OE 和 2OE）可用
于禁用输出，从而有效隔离总线。所有控制引脚
（xDIR 和 xOE）以 VCCA 为基准。
TSSOP (16)
SN74AXCH4T245RSV UQFN (16)
封装尺寸（标称值）
5.00mm x 4.40mm
2.60mm x 1.80mm
(1) 如需了解所有可用封装，请参阅产品说明书末尾的可订购产品
附录。
功能方框图
One of Two Transceiver Pairs
3 说明
SN74AXCH4T245 是一款使用两个独立可配置电源轨
的四位同相总线收发器。VCCA 和 VCCB 电源电压低至
0.65V 时，该器件可正常工作。A 端口用于跟踪
VCCA，该端口可支持 0.65V 至 3.6V 范围内的任何电
源电压。B 端口用于跟踪 VCCB，该端口可支持 0.65V
至 3.6V 范围内的任何电源电压。SN74AXCH4T245
器件与单电源系统兼容。
封装
SN74AXCH4T245PW
VCCA
VCCB
xDIR
xOE
Bus-Hold
xB1
xA1
Bus-Hold
Bus-Hold
xA2
xB2
Bus-Hold
Note: Bus-hold circuits are only present for data inputs, not control inputs
1
本文档旨在为方便起见，提供有关 TI 产品中文版本的信息，以确认产品的概要。 有关适用的官方英文版本的最新信息，请访问 www.ti.com，其内容始终优先。 TI 不保证翻译的准确
性和有效性。 在实际设计之前，请务必参考最新版本的英文版本。
English Data Sheet: SCES878
SN74AXCH4T245
ZHCSJI7 – MARCH 2019
www.ti.com.cn
目录
1
2
3
4
5
6
特性 ..........................................................................
应用 ..........................................................................
说明 ..........................................................................
修订历史记录 ...........................................................
Pin Configuration and Functions .........................
Specifications.........................................................
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11
6.12
6.13
6.14
6.15
7
7.1 Load Circuit and Voltage Waveforms ..................... 19
1
1
1
2
3
4
8
Detailed Description ............................................ 21
8.1
8.2
8.3
8.4
9
Absolute Maximum Ratings ...................................... 4
ESD Ratings.............................................................. 4
Recommended Operating Conditions....................... 5
Thermal Information .................................................. 5
Electrical Characteristics........................................... 6
Switching Characteristics, VCCA = 0.7 ± 0.05 V ........ 8
Switching Characteristics, VCCA = 0.8 ± 0.04 V ........ 9
Switching Characteristics, VCCA = 0.9 ± 0.045 V .... 10
Switching Characteristics, VCCA = 1.2 ± 0.1 V ........ 11
Switching Characteristics, VCCA = 1.5 ± 0.1 V ...... 12
Switching Characteristics, VCCA = 1.8 ± 0.15 V .... 13
Switching Characteristics, VCCA = 2.5 ± 0.2 V ...... 14
Switching Characteristics, VCCA = 3.3 ± 0.3 V ...... 15
Operating Characteristics: TA = 25°C ................... 16
Typical Characteristics .......................................... 18
Overview .................................................................
Functional Block Diagram .......................................
Feature Description.................................................
Device Functional Modes........................................
21
21
21
23
Application and Implementation ........................ 24
9.1 Application Information............................................ 24
9.2 Typical Application ................................................. 24
10 Power Supply Recommendations ..................... 26
11 Layout................................................................... 26
11.1 Layout Guidelines ................................................. 26
11.2 Layout Example .................................................... 26
12 器件和文档支持 ..................................................... 27
12.1
12.2
12.3
12.4
12.5
12.6
相关文档 ...........................................................
接收文档更新通知 .................................................
社区资源................................................................
商标 .......................................................................
静电放电警告.........................................................
术语表 ...................................................................
27
27
27
27
27
27
13 机械、封装和可订购信息 ....................................... 28
Parameter Measurement Information ................ 19
4 修订历史记录
2
日期
修订版本
说明
2019 年 3 月
*
初始发行版。
Copyright © 2019, Texas Instruments Incorporated
SN74AXCH4T245
www.ti.com.cn
ZHCSJI7 – MARCH 2019
5 Pin Configuration and Functions
PW Package
16-Pin TSSOP
Top View
VCCA
RSV Package
16-Pin UQFN
Transparent Top View
2DIR
3
14
2OE
1A1
4
13
1B1
1OE
1
12
2B2
1A2
5
1B2
VCCB
2
11
GND
2A1
6
12
11
2B1
VCCA
3
10
GND
2A2
7
2B2
4
9
2A2
GND
8
10
9
1DIR
13
5
6
7
8
2A1
14
1A2
15
1A1
16
2DIR
GND
2B1
1OE
1B2
15
1B1
VCCB
2OE
16
1DIR
1
2
Pin Functions
PIN
NAME
NO.
TYPE
DESCRIPTION
PW
RSV
1A1
4
6
I/O
Input/output 1A1. Referenced to VCCA.
1A2
5
7
I/O
Input/output 1A2. Referenced to VCCA.
1B1
13
15
I/O
Input/output 1B1. Referenced to VCCB.
1B2
12
14
I/O
Input/output 1B2. Referenced to VCCB.
1DIR
2
4
I
Direction-control input for ‘1’ ports
1OE
15
1
I
Tri-state output-mode enable. Pull OE high to place ‘1’ outputs in tri-state
mode. Referenced to VCCA.
2A1
6
8
I/O
Input/output 2A1. Referenced to VCCA.
2A2
7
9
I/O
Input/output 2A2. Referenced to VCCA.
2B1
11
13
I/O
Input/output 2B1. Referenced to VCCB.
2B2
10
12
I/O
Input/output 2B2. Referenced to VCCB.
2DIR
3
5
I
Direction-control input for ‘2’ ports
2OE
14
16
I
Tri-state output-mode enable. Pull OE high to place ‘2’ outputs in tri-state
mode. Referenced to VCCA.
GND
8, 9
10, 11
—
Ground
VCCA
1
3
—
A-port power supply voltage. 0.65 V ≤ VCCA ≤ 3.6 V
VCCB
16
2
—
B-port power supply voltage. 0.65 V ≤ VCCB ≤ 3.6 V
Copyright © 2019, Texas Instruments Incorporated
3
SN74AXCH4T245
ZHCSJI7 – MARCH 2019
www.ti.com.cn
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
MIN
MAX
UNIT
S
VCCA
Supply voltage A
–0.5
4.2
V
VCCB
Supply voltage B
–0.5
4.2
V
I/O Ports (A Port)
–0.5
4.2
I/O Ports (B Port)
–0.5
4.2
Control Inputs
–0.5
4.2
A Port
–0.5
4.2
B Port
–0.5
4.2
A Port
–0.5 VCCA + 0.2
B Port
–0.5 VCCB + 0.2
Input Voltage (2)
VI
VO
Voltage applied to any output in the high-impedance or power-off state (2)
VO
Voltage applied to any output in the high or low state (2) (3)
IIK
Input clamp current
VI < 0
–50
IOK
Output clamp current
VO < 0
–50
IO
Continuous output current
Continuous current through VCC or GND
Tj
Junction Temperature
Tstg
Storage temperature
(1)
(2)
(3)
V
V
V
mA
mA
–50
50
mA
–100
100
mA
150
°C
150
°C
–65
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
The input voltage and output negative-voltage ratings may be exceeded if the input and output current ratings are observed.
The output positive-voltage rating may be exceeded up to 4.2 V maximum if the output current rating is observed.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
4
Electrostatic discharge
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±8000
Charged device model (CDM), per JEDEC specification JESD22-C101 (2)
±1000
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
Copyright © 2019, Texas Instruments Incorporated
SN74AXCH4T245
www.ti.com.cn
ZHCSJI7 – MARCH 2019
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted) (1) (2) (3)
MIN
MAX
UNIT
VCCA
Supply voltage A
0.65
3.6
V
VCCB
Supply voltage B
0.65
3.6
V
Data Inputs
VCCI = 0.65 V - 0.75 V
VCCI x 0.70
VCCI = 0.76 V - 1 V
VCCI x 0.70
VCCI = 1.1 V - 1.95 V
VCCI x 0.65
VCCI = 2.3 V - 2.7 V
VIH
High-level input voltage
Control Inputs(xDIR, xOE)
Referenced to VCCA
VCCI x 0.65
VCCA = 0.65 V - 0.75 V
VCCA x 0.70
VCCA = 0.76 V - 1 V
VCCA x 0.70
VCCA = 1.1 V - 1.95 V
VCCA x 0.65
VCCA = 2.3 V - 2.7 V
VCCA = 3 V - 3.6 V
Data Inputs
VIL
Low-level input voltage
Control Inputs(xDIR, xOE)
Referenced to VCCA
1.6
VCCI = 3 V - 3.6 V
1.6
VCCA x 0.65
VCCI = 0.65 V - 0.75 V
VCCI x 0.30
VCCI = 0.76 V - 1 V
VCCI x 0.30
VCCI = 1.1 V - 1.95 V
VCCI x 0.35
VCCI = 2.3 V - 2.7 V
0.7
VCCI = 3 V - 3.6 V
0.8
VCCA = 0.65 V - 0.75 V
VCCA x 0.30
VCCA = 0.76 V - 1 V
VCCA x 0.30
VCCA = 1.1 V - 1.95 V
VCCA x 0.35
VCCA = 2.3 V - 2.7 V
0.7
VCCA = 3 V - 3.6 V
VI
Input voltage
0.8
(3)
0
3.6
Active State
0
VCCO
Tri-State
0
3.6
10
ns/V
–40
125
°C
VO
Output voltage
Δt/Δv (2)
Input transition rise and fall time
TA
Operating free-air temperature
(1)
(2)
(3)
V
V
V
VCCI is the VCC associated with the input port.
VCCO is the VCC associated with the output port.
All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report,
Implications of Slow or Floating CMOS Inputs, SCBA004.
6.4 Thermal Information
SN74AXCH4T245
THERMAL METRIC
(1)
PW (TSSOP)
RSV (UQFN)
16 PINS
16 PINS
UNIT
RθJA
Junction-to-ambient thermal resistance
126.9
130.1
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
49.3
70.3
°C/W
RθJB
Junction-to-board thermal resistance
74.3
57.4
°C/W
ψJT
Junction-to-top characterization parameter
8.1
4.6
°C/W
ψJB
Junction-to-board characterization parameter
73.4
55.8
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
Copyright © 2019, Texas Instruments Incorporated
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SN74AXCH4T245
ZHCSJI7 – MARCH 2019
www.ti.com.cn
6.5 Electrical Characteristics
over operating free-air temperature range (unless otherwise noted)
(1) (2)
Operating free-air temperature (TA)
PARAMETER
TEST CONDITIONS
VCCA
VCCB
-40°C to 85°C
MIN TYP (3)
VOH
VOL
IBHL
High-level
output
voltage
Low-level
output
voltage
Bus-hold low
sustaining
current (Port
A or Port B)
(4)
IBHH
Bus-hold
high
sustaining
current (Port
A or Port B)
(5)
(1)
(2)
(3)
(4)
(5)
6
-40°C to 125°C
MAX
MIN TYP (3)
UNIT
MAX
VCCO
– 0.1
VCCO
– 0.1
0.65 V
0.55
0.55
0.76 V
0.58
0.58
0.85 V
0.85 V
0.65
0.65
IOH = -3 mA
1.1 V
1.1 V
0.85
0.85
IOH = -6 mA
1.4 V
1.4 V
1.05
1.05
IOH = -8 mA
1.65 V
1.65 V
1.2
1.2
IOH = -9 mA
2.3 V
2.3 V
1.75
1.75
IOH = -12 mA
3V
3V
IOL = 100 µA
0.7 V - 3.6 V
0.7 V - 3.6 V
0.1
0.1
IOL = 50 µA
0.65 V
0.65 V
0.1
0.1
IOL = 200 µA
0.76 V
0.76 V
0.18
0.18
IOL = 500 µA
0.85 V
0.85 V
0.2
0.2
IOL = 3 mA
1.1 V
1.1 V
0.25
0.25
IOL = 6 mA
1.4 V
1.4 V
0.35
0.35
IOL = 8 mA
1.65 V
1.65 V
0.45
0.45
IOL = 9 mA
2.3 V
2.3 V
0.55
0.55
IOL = 12 mA
3V
3V
0.7
0.7
VI = 0.20 V
0.65 V
0.65 V
4
VI = 0.23 V
0.76 V
0.76 V
8
7
VI = 0.26 V
0.85 V
0.85 V
10
10
VI = 0.39 V
1.1 V
1.1 V
20
20
VI = 0.49 V
1.4 V
1.4 V
40
30
VI = 0.58 V
1.65 V
1.65 V
55
45
VI = 0.7 V
2.3 V
2.3 V
VI = 0.8 V
3V
3V
VI = 0.20 V
0.65 V
VI = 0.23 V
0.76 V
VI = 0.26 V
VI = 0.39 V
VI = VIH
VI = VIL
IOH = -100 µA
0.7 V - 3.6 V
0.7 V - 3.6 V
IOH = -50 µA
0.65 V
IOH = -200 µA
0.76 V
IOH = -500 µA
2.3
V
2.3
V
4
90
80
145
135
0.65 V
–4
–4
0.76 V
–8
–7
0.85 V
0.85 V
–10
–10
1.1 V
1.1 V
–20
–20
VI = 0.49 V
1.4 V
1.4 V
–40
–30
VI = 0.58 V
1.65 V
1.65 V
–55
–45
VI = 0.7 V
2.3 V
2.3 V
–90
–80
VI = 0.8 V
3V
3V
–145
–135
µA
µA
VCCI is the VCC associated with the input port.
VCCO is the VCC associated with the output port.
All typical data is taken at 25°C.
The bus-hold circuit can sink at least the minimum low sustaining current at VIL max. IBHL should be measured after lowering VIN to GND
and then raising it to VIL max.
The bus-hold circuit can source at least the minimum high sustaining current at VIH min. IBHH should be measured after raising VIN to
VCC and then lowering it to VIH min.
Copyright © 2019, Texas Instruments Incorporated
SN74AXCH4T245
www.ti.com.cn
ZHCSJI7 – MARCH 2019
Electrical Characteristics (continued)
over operating free-air temperature range (unless otherwise noted) (1)(2)
Operating free-air temperature (TA)
PARAMETER
TEST CONDITIONS
VCCA
VCCB
-40°C to 85°C
MIN TYP (3)
IBHLO
Bus-hold low
overdrive
current (Port
A or Port B)
VI = 0 to VCC
(6)
IBHHO
Bus-hold
high
overdrive
current (Port
A or Port B)
VI = 0 to VCC
(7)
Control inputs (xDIR,
Input leakage xOE): VI = VCCA or GND
current
Data Inputs (xAx, xBx)
VI = VCCI or GND
II
Partial power
down current
Ioff
0.75 V
0.75 V
40
40
0.84 V
0.84 V
50
50
0.95 V
0.95 V
65
65
1.3 V
1.3 V
105
105
1.6 V
1.6 V
150
150
1.95 V
1.95 V
205
205
2.7 V
2.7 V
335
335
3.6 V
3.6 V
480
480
0.75 V
0.75 V
–40
–40
0.84 V
0.84 V
–50
–50
0.95 V
0.95 V
–65
–65
1.3 V
1.3 V
–105
–105
1.6 V
1.6 V
–150
–150
1.95 V
1.95 V
–205
–205
2.7 V
2.7 V
–335
–335
3.6 V
3.6 V
–480
–480
UNIT
MAX
µA
µA
–0.5
0.5
–1
1
µA
0.65 V- 3.6 V 0.65 V- 3.6 V
–4
4
–8
8
µA
A Port: VI or VO = 0 V 3.6 V
0V
0 V - 3.6 V
–8
8
–12
12
B Port: VI or VO = 0 V 3.6 V
0 V - 3.6 V
0V
–8
8
–12
12
3.6 V
3.6 V
–4
4
–8
8
Tri-state
output
current (8)
A or B Port
VI = VCCI or GND, VO =
VCCO or GND, OE = VIH
ICCA
VCCA supply
current
VI =
VCCI or
GND
ICCB
MIN TYP (3)
0.65 V- 3.6 V 0.65 V- 3.6 V
IOZ
VCCB supply
current
-40°C to 125°C
MAX
µA
0.65 V- 3.6 V 0.65 V- 3.6 V
IO = 0
0V
3.6 V
3.6 V
0V
13
–2
IO = 0
IO = 0
0V
3.6 V
3.6 V
0V
26
–12
0.65 V- 3.6 V 0.65 V- 3.6 V
VI =
VCCI or
GND
µA
8
16
13
26
8
–2
µA
16
µA
40
µA
–12
ICCA +
ICCB
Combined
supply
current
VI =
VCCI or
GND
Ci
Control Input
Capacitance
VI = 3.3 V or GND
3.3 V
3.3 V
4.5
4.5
pF
Cio
Data I/O
Capacitance
OE = VCCA, VO = 1.65V
DC +1 MHz -16 dBm sine
wave
3.3 V
3.3 V
7.4
7.4
pF
(6)
(7)
(8)
0.65 V- 3.6 V 0.65 V- 3.6 V
20
An external driver must source at least IBHLO to switch this node from low to high.
An external driver must sink at least IBHHO to switch this node from high to low.
For I/O ports, the parameter IOZ includes the input leakage current.
Copyright © 2019, Texas Instruments Incorporated
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ZHCSJI7 – MARCH 2019
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6.6 Switching Characteristics, VCCA = 0.7 ± 0.05 V
See Figure 5 and Table 1 for test circuit and loading. See Figure 6, Figure 7, and Figure 8 for measurement waveforms.
B-Port Supply Voltage (VCCB)
PARAMETER
FROM
A
tpd
tdis
B
A
OE
A
Disable time
OE
B
A
Enable time
OE
8
B
Propagation
delay
OE
ten
TO
B
Test Conditions
0.7 ± 0.05 V
0.8 ± 0.04 V
0.9 ± 0.045 V
1.2 ± 0.1 V
1.5 ± 0.1 V
2.5 ± 0.2 V
3.3 ± 0.3 V
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
1.8 ± 0.15 V
MIN
MAX
MIN
MAX
MIN
MAX
-40°C to 85°C
0.5
161
0.5
109
0.5
78
0.5
41
0.5
38
0.5
41
0.5
68
0.5
181
-40°C to 125°C
0.5
161
0.5
109
0.5
78
0.5
41
0.5
38
0.5
41
0.5
68
0.5
181
-40°C to 85°C
0.5
161
0.5
134
0.5
112
0.5
59
0.5
22
0.5
15
0.5
11
0.5
10
-40°C to 125°C
0.5
161
0.5
134
0.5
112
0.5
59
0.5
22
0.5
16
0.5
11
0.5
10
-40°C to 85°C
0.5
159
0.5
159
0.5
159
0.5
159
0.5
159
0.5
159
0.5
159
0.5
159
-40°C to 125°C
0.5
159
0.5
159
0.5
159
0.5
159
0.5
159
0.5
159
0.5
159
0.5
159
-40°C to 85°C
0.5
158
0.5
122
0.5
102
0.5
55
0.5
54
0.5
56
0.5
65
0.5
125
-40°C to 125°C
0.5
158
0.5
122
0.5
102
0.5
55
0.5
54
0.5
56
0.5
65
0.5
125
-40°C to 85°C
0.5
243
0.5
243
0.5
243
0.5
243
0.5
243
0.5
243
0.5
243
0.5
243
-40°C to 125°C
0.5
243
0.5
243
0.5
243
0.5
243
0.5
243
0.5
243
0.5
243
0.5
243
-40°C to 85°C
0.5
292
0.5
192
0.5
134
0.5
87
0.5
73
0.5
69
0.5
70
0.5
148
-40°C to 125°C
0.5
292
0.5
192
0.5
134
0.5
88
0.5
74
0.5
69
0.5
70
0.5
148
UNIT
ns
ns
ns
Copyright © 2019, Texas Instruments Incorporated
SN74AXCH4T245
www.ti.com.cn
ZHCSJI7 – MARCH 2019
6.7 Switching Characteristics, VCCA = 0.8 ± 0.04 V
See Figure 5 and Table 1 for test circuit and loading. See Figure 6, Figure 7, and Figure 8 for measurement waveforms.
B-Port Supply Voltage (VCCB)
PARAMETER
FROM
A
tpd
tdis
B
Propagation
delay
B
A
OE
A
Disable time
OE
OE
ten
TO
B
A
Enable time
OE
B
Test Conditions
1.2 ± 0.1 V
1.5 ± 0.1 V
2.5 ± 0.2 V
3.3 ± 0.3 V
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
-40°C to 85°C
0.5
134
0.5
90
0.5
64
0.5
30
0.5
24
0.5
23
0.5
25
0.5
34
-40°C to 125°C
0.5
134
0.5
90
0.5
64
0.5
30
0.5
24
0.5
23
0.5
25
0.5
34
-40°C to 85°C
0.5
109
0.5
90
0.5
72
0.5
39
0.5
22
0.5
15
0.5
11
0.5
10
-40°C to 125°C
0.5
109
0.5
90
0.5
72
0.5
39
0.5
22
0.5
15
0.5
11
0.5
10
-40°C to 85°C
0.5
110
0.5
110
0.5
110
0.5
110
0.5
110
0.5
110
0.5
110
0.5
110
-40°C to 125°C
0.5
110
0.5
110
0.5
110
0.5
110
0.5
110
0.5
110
0.5
110
0.5
110
-40°C to 85°C
0.5
147
0.5
111
0.5
91
0.5
42
0.5
36
0.5
35
0.5
37
0.5
47
-40°C to 125°C
0.5
147
0.5
111
0.5
91
0.5
42
0.5
36
0.5
35
0.5
37
0.5
47
-40°C to 85°C
0.5
143
0.5
143
0.5
143
0.5
143
0.5
143
0.5
143
0.5
143
0.5
143
-40°C to 125°C
0.5
143
0.5
143
0.5
143
0.5
143
0.5
143
0.5
143
0.5
143
0.5
143
-40°C to 85°C
0.5
253
0.5
164
0.5
117
0.5
71
0.5
57
0.5
52
0.5
47
0.5
53
-40°C to 125°C
0.5
253
0.5
164
0.5
117
0.5
73
0.5
58
0.5
53
0.5
48
0.5
53
Copyright © 2019, Texas Instruments Incorporated
0.7 ± 0.05 V
0.8 ± 0.04 V
0.9 ± 0.045 V
1.8 ± 0.15 V
UNIT
ns
ns
ns
9
SN74AXCH4T245
ZHCSJI7 – MARCH 2019
www.ti.com.cn
6.8 Switching Characteristics, VCCA = 0.9 ± 0.045 V
See Figure 5 and Table 1 for test circuit and loading. See Figure 6, Figure 7, and Figure 8 for measurement waveforms.
B-Port Supply Voltage (VCCB)
PARAMETER
FROM
A
tpd
tdis
B
A
OE
A
Disable time
OE
B
A
Enable time
OE
10
B
Propagation
delay
OE
ten
TO
B
Test Conditions
0.7 ± 0.05 V
0.8 ± 0.04 V
0.9 ± 0.045 V
1.2 ± 0.1 V
1.5 ± 0.1 V
2.5 ± 0.2 V
3.3 ± 0.3 V
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
1.8 ± 0.15 V
MIN
MAX
MIN
MAX
MIN
MAX
-40°C to 85°C
0.5
112
0.5
72
0.5
54
0.5
24
0.5
19
0.5
17
0.5
16
0.5
19
-40°C to 125°C
0.5
112
0.5
72
0.5
54
0.5
24
0.5
19
0.5
17
0.5
16
0.5
19
-40°C to 85°C
0.5
78
0.5
64
0.5
54
0.5
27
0.5
19
0.5
14
0.5
10
0.5
10
-40°C to 125°C
0.5
78
0.5
64
0.5
54
0.5
27
0.5
19
0.5
14
0.5
10
0.5
10
-40°C to 85°C
0.5
81
0.5
81
0.5
81
0.5
81
0.5
81
0.5
81
0.5
81
0.5
81
-40°C to 125°C
0.5
82
0.5
82
0.5
82
0.5
82
0.5
82
0.5
82
0.5
82
0.5
82
-40°C to 85°C
0.5
141
0.5
106
0.5
85
0.5
36
0.5
29
0.5
27
0.5
26
0.5
30
-40°C to 125°C
0.5
141
0.5
106
0.5
85
0.5
37
0.5
30
0.5
28
0.5
26
0.5
30
-40°C to 85°C
0.5
84
0.5
84
0.5
84
0.5
84
0.5
84
0.5
84
0.5
84
0.5
84
-40°C to 125°C
0.5
84
0.5
84
0.5
84
0.5
84
0.5
84
0.5
84
0.5
84
0.5
84
-40°C to 85°C
0.5
229
0.5
149
0.5
107
0.5
63
0.5
48
0.5
43
0.5
37
0.5
38
-40°C to 125°C
0.5
229
0.5
149
0.5
107
0.5
65
0.5
50
0.5
45
0.5
39
0.5
39
UNIT
ns
ns
ns
Copyright © 2019, Texas Instruments Incorporated
SN74AXCH4T245
www.ti.com.cn
ZHCSJI7 – MARCH 2019
6.9 Switching Characteristics, VCCA = 1.2 ± 0.1 V
See Figure 5 and Table 1 for test circuit and loading. See Figure 6, Figure 7, and Figure 8 for measurement waveforms.
B-Port Supply Voltage (VCCB)
PARAMETER
FROM
A
tpd
tdis
B
Propagation
delay
B
A
OE
A
Disable time
OE
OE
ten
TO
B
A
Enable time
OE
B
Test Conditions
1.2 ± 0.1 V
1.5 ± 0.1 V
2.5 ± 0.2 V
3.3 ± 0.3 V
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
-40°C to 85°C
0.5
60
0.5
39
0.5
27
0.5
15
0.5
11
0.5
10
0.5
8
0.5
9
-40°C to 125°C
0.5
60
0.5
39
0.5
27
0.5
15
0.5
12
0.5
10
0.5
9
0.5
9
-40°C to 85°C
0.5
41
0.5
30
0.5
24
0.5
15
0.5
11
0.5
9
0.5
7
0.5
7
-40°C to 125°C
0.5
41
0.5
30
0.5
24
0.5
15
0.5
11
0.5
9
0.5
7
0.5
7
-40°C to 85°C
0.5
28
0.5
28
0.5
28
0.5
28
0.5
28
0.5
28
0.5
28
0.5
28
-40°C to 125°C
0.5
30
0.5
30
0.5
30
0.5
30
0.5
30
0.5
30
0.5
30
0.5
30
-40°C to 85°C
0.5
133
0.5
100
0.5
79
0.5
29
0.5
22
0.5
20
0.5
17
0.5
17
-40°C to 125°C
0.5
134
0.5
100
0.5
80
0.5
31
0.5
23
0.5
21
0.5
18
0.5
18
-40°C to 85°C
0.5
37
0.5
37
0.5
37
0.5
37
0.5
37
0.5
37
0.5
37
0.5
37
-40°C to 125°C
0.5
39
0.5
39
0.5
39
0.5
39
0.5
39
0.5
39
0.5
39
0.5
39
-40°C to 85°C
0.5
168
0.5
109
0.5
77
0.5
51
0.5
37
0.5
31
0.5
25
0.5
23
-40°C to 125°C
0.5
168
0.5
109
0.5
78
0.5
53
0.5
39
0.5
34
0.5
27
0.5
24
Copyright © 2019, Texas Instruments Incorporated
0.7 ± 0.05 V
0.8 ± 0.04 V
0.9 ± 0.045 V
1.8 ± 0.15 V
UNIT
ns
ns
ns
11
SN74AXCH4T245
ZHCSJI7 – MARCH 2019
www.ti.com.cn
6.10 Switching Characteristics, VCCA = 1.5 ± 0.1 V
See Figure 5 and Table 1 for test circuit and loading. See Figure 6, Figure 7, and Figure 8 for measurement waveforms.
B-Port Supply Voltage (VCCB)
PARAMETER
FROM
A
tpd
tdis
B
A
OE
A
Disable time
OE
B
A
Enable time
OE
12
B
Propagation
delay
OE
ten
TO
B
Test Conditions
0.7 ± 0.05 V
0.8 ± 0.04 V
0.9 ± 0.045 V
1.2 ± 0.1 V
1.5 ± 0.1 V
2.5 ± 0.2 V
3.3 ± 0.3 V
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
1.8 ± 0.15 V
MIN
MAX
MIN
MAX
MIN
MAX
UNIT
-40°C to 85°C
0.5
22
0.5
22
0.5
19
0.5
11
0.5
9
0.5
8
0.5
7
0.5
6
-40°C to 125°C
0.5
22
0.5
22
0.5
19
0.5
11
0.5
9
0.5
8
0.5
7
0.5
6
-40°C to 85°C
0.5
38
0.5
24
0.5
19
0.5
11
0.5
9
0.5
8
0.5
5
0.5
5
-40°C to 125°C
0.5
38
0.5
24
0.5
19
0.5
11
0.5
9
0.5
8
0.5
6
0.5
5
-40°C to 85°C
0.5
19
0.5
19
0.5
19
0.5
19
0.5
19
0.5
19
0.5
19
0.5
19
-40°C to 125°C
0.5
21
0.5
21
0.5
21
0.5
21
0.5
21
0.5
21
0.5
21
0.5
21
-40°C to 85°C
0.5
131
0.5
98
0.5
78
0.5
27
0.5
20
0.5
18
0.5
14
0.5
14
-40°C to 125°C
0.5
132
0.5
98
0.5
78
0.5
29
0.5
21
0.5
19
0.5
15
0.5
15
-40°C to 85°C
0.5
23
0.5
23
0.5
23
0.5
23
0.5
23
0.5
23
0.5
23
0.5
23
-40°C to 125°C
0.5
25
0.5
25
0.5
25
0.5
25
0.5
25
0.5
25
0.5
25
0.5
25
-40°C to 85°C
0.5
109
0.5
84
0.5
67
0.5
43
0.5
31
0.5
26
0.5
20
0.5
18
-40°C to 125°C
0.5
109
0.5
84
0.5
68
0.5
45
0.5
34
0.5
29
0.5
22
0.5
19
ns
ns
ns
Copyright © 2019, Texas Instruments Incorporated
SN74AXCH4T245
www.ti.com.cn
ZHCSJI7 – MARCH 2019
6.11 Switching Characteristics, VCCA = 1.8 ± 0.15 V
See Figure 5 and Table 1 for test circuit and loading. See Figure 6, Figure 7, and Figure 8 for measurement waveforms.
B-Port Supply Voltage (VCCB)
PARAMETER
FROM
A
tpd
tdis
B
Propagation
delay
B
A
OE
A
Disable time
OE
OE
ten
TO
B
A
Enable time
OE
B
Test Conditions
1.2 ± 0.1 V
1.5 ± 0.1 V
2.5 ± 0.2 V
3.3 ± 0.3 V
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
-40°C to 85°C
0.5
15
0.5
15
0.5
14
0.5
9
0.5
8
0.5
7
0.5
6
0.5
6
-40°C to 125°C
0.5
16
0.5
15
0.5
14
0.5
9
0.5
8
0.5
7
0.5
6
0.5
6
-40°C to 85°C
0.5
41
0.5
23
0.5
17
0.5
10
0.5
8
0.5
7
0.5
5
0.5
4
-40°C to 125°C
0.5
41
0.5
23
0.5
17
0.5
10
0.5
8
0.5
7
0.5
5
0.5
4
-40°C to 85°C
0.5
17
0.5
17
0.5
17
0.5
17
0.5
17
0.5
17
0.5
17
0.5
17
-40°C to 125°C
0.5
18
0.5
18
0.5
18
0.5
18
0.5
18
0.5
18
0.5
18
0.5
18
-40°C to 85°C
0.5
129
0.5
98
0.5
77
0.5
27
0.5
19
0.5
17
0.5
13
0.5
13
-40°C to 125°C
0.5
131
0.5
98
0.5
77
0.5
28
0.5
21
0.5
18
0.5
14
0.5
14
-40°C to 85°C
0.5
17
0.5
17
0.5
17
0.5
17
0.5
17
0.5
17
0.5
17
0.5
17
-40°C to 125°C
0.5
19
0.5
19
0.5
19
0.5
19
0.5
19
0.5
19
0.5
19
0.5
19
-40°C to 85°C
0.5
102
0.5
73
0.5
60
0.5
38
0.5
28
0.5
24
0.5
19
0.5
16
-40°C to 125°C
0.5
102
0.5
75
0.5
62
0.5
41
0.5
31
0.5
26
0.5
20
0.5
18
Copyright © 2019, Texas Instruments Incorporated
0.7 ± 0.05 V
0.8 ± 0.04 V
0.9 ± 0.045 V
1.8 ± 0.15 V
UNIT
ns
ns
ns
13
SN74AXCH4T245
ZHCSJI7 – MARCH 2019
www.ti.com.cn
6.12 Switching Characteristics, VCCA = 2.5 ± 0.2 V
See Figure 5 and Table 1 for test circuit and loading. See Figure 6, Figure 7, and Figure 8 for measurement waveforms.
B-Port Supply Voltage (VCCB)
PARAMETER
FROM
A
tpd
tdis
B
A
OE
A
Disable time
OE
B
A
Enable time
OE
14
B
Propagation
delay
OE
ten
TO
B
Test Conditions
0.7 ± 0.05 V
0.8 ± 0.04 V
0.9 ± 0.045 V
1.2 ± 0.1 V
1.5 ± 0.1 V
2.5 ± 0.2 V
3.3 ± 0.3 V
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
1.8 ± 0.15 V
MIN
MAX
MIN
MAX
MIN
MAX
UNIT
-40°C to 85°C
0.5
11
0.5
11
0.5
10
0.5
7
0.5
6
0.5
5
0.5
5
0.5
5
-40°C to 125°C
0.5
11
0.5
11
0.5
10
0.5
7
0.5
6
0.5
5
0.5
5
0.5
5
-40°C to 85°C
0.5
68
0.5
25
0.5
17
0.5
8
0.5
7
0.5
6
0.5
5
0.5
4
-40°C to 125°C
0.5
68
0.5
25
0.5
17
0.5
9
0.5
7
0.5
6
0.5
5
0.5
4
-40°C to 85°C
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
-40°C to 125°C
0.5
13
0.5
13
0.5
13
0.5
13
0.5
13
0.5
13
0.5
13
0.5
13
-40°C to 85°C
0.5
128
0.5
96
0.5
76
0.5
26
0.5
18
0.5
16
0.5
12
0.5
12
-40°C to 125°C
0.5
129
0.5
96
0.5
77
0.5
27
0.5
20
0.5
17
0.5
13
0.5
13
-40°C to 85°C
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
-40°C to 125°C
0.5
13
0.5
13
0.5
13
0.5
13
0.5
13
0.5
13
0.5
13
0.5
13
-40°C to 85°C
0.5
120
0.5
69
0.5
54
0.5
33
0.5
24
0.5
20
0.5
16
0.5
14
-40°C to 125°C
0.5
120
0.5
70
0.5
56
0.5
36
0.5
26
0.5
22
0.5
18
0.5
15
ns
ns
ns
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SN74AXCH4T245
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ZHCSJI7 – MARCH 2019
6.13 Switching Characteristics, VCCA = 3.3 ± 0.3 V
See Figure 5 and Table 1 for test circuit and loading. See Figure 6, Figure 7, and Figure 8 for measurement waveforms.
B-Port Supply Voltage (VCCB)
PARAMETER
FROM
A
tpd
tdis
B
Propagation
delay
B
A
OE
A
Disable time
OE
ten
TO
B
OE
A
OE
B
Enable time
Test Condtions
1.2 ± 0.1 V
1.5 ± 0.1 V
2.5 ± 0.2 V
3.3 ± 0.3 V
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
-40°C to 85°C
0.5
10
0.5
10
0.5
10
0.5
7
0.5
5
0.5
5
0.5
5
0.5
4
-40°C to 125°C
0.5
10
0.5
10
0.5
10
0.5
7
0.5
5
0.5
5
0.5
5
0.5
4
-40°C to 85°C
0.5
182
0.5
34
0.5
19
0.5
9
0.5
6
0.5
5
0.5
5
0.5
4
-40°C to 125°C
0.5
182
0.5
34
0.5
19
0.5
9
0.5
6
0.5
6
0.5
5
0.5
4
-40°C to 85°C
0.5
11
0.5
11
0.5
11
0.5
11
0.5
11
0.5
11
0.5
11
0.5
11
-40°C to 125°C
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
0.5
12
-40°C to 85°C
0.5
142
0.5
96
0.5
76
0.5
26
0.5
18
0.5
16
0.5
12
0.5
11
-40°C to 125°C
0.5
142
0.5
97
0.5
77
0.5
27
0.5
19
0.5
17
0.5
13
0.5
12
-40°C to 85°C
0.5
9
0.5
9
0.5
9
0.5
9
0.5
9
0.5
9
0.5
9
0.5
9
-40°C to 125°C
0.5
11
0.5
11
0.5
11
0.5
11
0.5
11
0.5
11
0.5
11
0.5
11
-40°C to 85°C
0.5
194
0.5
82
0.5
57
0.5
33
0.5
22
0.5
18
0.5
14
0.5
13
-40°C to 125°C
0.5
194
0.5
82
0.5
58
0.5
35
0.5
24
0.5
20
0.5
16
0.5
14
Copyright © 2019, Texas Instruments Incorporated
0.7 ± 0.05 V
0.8 ± 0.04 V
0.9 ± 0.045 V
1.8 ± 0.15 V
UNIT
ns
ns
ns
15
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ZHCSJI7 – MARCH 2019
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6.14 Operating Characteristics: TA = 25°C
PARAMETER
Power Dissipation Capacitance
per transceiver (A to B: outputs
enabled)
Power Dissipation Capacitance
per transceiver (A to B: outputs
disabled)
TEST CONDITIONS
CL = 0, RL = Open f = 1
MHz, tr = tf = 1 ns
CL = 0, RL = Open f = 1
MHz, tr = tf = 1 ns
CpdA
Power Dissipation Capacitance
per transceiver (B to A: outputs
enabled)
Power Dissipation Capacitance
per transceiver (B to A: outputs
disabled)
16
CL = 0, RL = Open f = 1
MHz, tr = tf = 1 ns
CL = 0, RL = Open f = 1
MHz, tr = tf = 1 ns
VCCA
VCCB
MIN
TYP
0.7 V
0.7 V
2.2
0.8 V
0.8 V
2.3
0.9 V
0.9 V
2.3
1.2 V
1.2 V
2.3
1.5 V
1.5 V
2.2
1.8 V
1.8 V
2.2
2.5 V
2.5 V
2.5
3.3 V
3.3 V
2.6
0.7 V
0.7 V
1.5
0.8 V
0.8 V
1.7
0.9 V
0.9 V
1.7
1.2 V
1.2 V
1.7
1.5 V
1.5 V
1.5
1.8 V
1.8 V
1.5
2.5 V
2.5 V
1.8
3.3 V
3.3 V
2.1
0.7 V
0.7 V
12.6
0.8 V
0.8 V
12.4
0.9 V
0.9 V
12.4
1.2 V
1.2 V
12.8
1.5 V
1.5 V
13.3
1.8 V
1.8 V
14.6
2.5 V
2.5 V
18.0
3.3 V
3.3 V
21.1
0.7 V
0.7 V
1.1
0.8 V
0.8 V
1.1
0.9 V
0.9 V
1.0
1.2 V
1.2 V
1.0
1.5 V
1.5 V
1.0
1.8 V
1.8 V
0.9
2.5 V
2.5 V
0.9
3.3 V
3.3 V
0.9
MAX
UNIT
pF
pF
pF
pF
Copyright © 2019, Texas Instruments Incorporated
SN74AXCH4T245
www.ti.com.cn
ZHCSJI7 – MARCH 2019
Operating Characteristics: TA = 25°C (continued)
PARAMETER
Power Dissipation Capacitance
per transceiver (A to B: outputs
enabled)
Power Dissipation Capacitance
per transceiver (A to B: outputs
disabled)
TEST CONDITIONS
CL = 0, RL = Open f = 1
MHz, tr = tf = 1 ns
CL = 0, RL = Open f = 1
MHz, tr = tf = 1 ns
CpdB
Power Dissipation Capacitance
per transceiver (B to A: outputs
enabled)
Power Dissipation Capacitance
per transceiver (B to A: outputs
disabled)
版权 © 2019, Texas Instruments Incorporated
CL = 0, RL = Open f = 1
MHz, tr = tf = 1 ns
CL = 0, RL = Open f = 1
MHz, tr = tf = 1 ns
VCCA
VCCB
MIN
TYP
0.7 V
0.7 V
12.6
0.8 V
0.8 V
12.4
0.9 V
0.9 V
12.4
1.2 V
1.2 V
12.8
1.5 V
1.5 V
13.3
1.8 V
1.8 V
14.6
2.5 V
2.5 V
17.8
3.3 V
3.3 V
21.0
0.7 V
0.7 V
1.1
0.8 V
0.8 V
1.1
0.9 V
0.9 V
1.0
1.2 V
1.2 V
1.0
1.5 V
1.5 V
1.0
1.8 V
1.8 V
0.9
2.5 V
2.5 V
0.9
3.3 V
3.3 V
0.9
0.7 V
0.7 V
2.2
0.8 V
0.8 V
2.2
0.9 V
0.9 V
2.2
1.2 V
1.2 V
2.0
1.5 V
1.5 V
2.0
1.8 V
1.8 V
1.9
2.5 V
2.5 V
2.0
3.3 V
3.3 V
2.6
0.7 V
0.7 V
1.6
0.8 V
0.8 V
1.5
0.9 V
0.9 V
1.6
1.2 V
1.2 V
1.4
1.5 V
1.5 V
1.3
1.8 V
1.8 V
1.2
2.5 V
2.5 V
1.4
3.3 V
3.3 V
1.9
MAX
UNIT
pF
pF
pF
pF
17
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6.15 Typical Characteristics
1.25
1.2
1.15
1.1
1.05
1
0.95
0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
3.4
VCC = 1.8V
VCC = 2.5V
VCC = 3.3V
3.2
3
2.6
VOH (V)
VOH (V)
2.8
2.4
2.2
2
1.8
1.6
1.4
0
2
4
6
8
10
12
IOH (mA)
14
16
18
0.5
1
1.5
2
D001
2.5
3
IOH (mA)
3.5
4
4.5
5
D001
图 2. Typical (TA=25°C) Output High Voltage (VOH) vs Source
Current (IOH)
220
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
-50
200
180
160
140
VOL (mV)
VOL (mV)
0
20
图 1. Typical (TA=25°C) Output High Voltage (VOH) vs Source
Current (IOH)
120
100
80
60
40
VCC = 1.8V
VCC = 2.5V
VCC = 3.3V
VCC = 0.7V
VCC = 1.2V
20
0
0
2
4
6
8
10
12
IOL (mA)
14
16
18
20
D001
图 3. Typical (TA=25°C) Output High Voltage (VOL) vs Sink
Current (IOL)
18
VCC = 0.7V
VCC = 1.2V
0
0.5
1
1.5
2
2.5
3
IOL (mA)
3.5
4
4.5
5
D001
图 4. Typical (TA=25°C) Output High Voltage (VOL) vs Sink
Current (IOL)
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SN74AXCH4T245
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ZHCSJI7 – MARCH 2019
7 Parameter Measurement Information
7.1 Load Circuit and Voltage Waveforms
Unless otherwise noted, all input pulses are supplied by generators having the following characteristics:
• f = 1 MHz
• ZO = 50 Ω
• dv/dt ≤ 1 ns/V
Measurement Point
2 x VCCO
S1
RL
Open
Output Pin
Under Test
GND
CL(1)
(1)
RL
CL includes probe and jig capacitance.
图 5. Load Circuit
表 1. Load Circuit Conditions
Parameter
VCCO
RL
CL
S1
VTP
Δt/Δv
Input transition rise or fall rate
0.65 V – 3.6 V
1 MΩ
15 pF
Open
N/A
1.1 V – 3.6 V
2 kΩ
15 pF
Open
N/A
tpd
Propagation (delay) time
0.65 V – 0.95
V
20 kΩ
15 pF
Open
N/A
ten, tdis Enable time, disable time
ten, tdis Enable time, disable time
3 V – 3.6 V
2 kΩ
15 pF
2 × VCCO
0.3 V
1.65 V – 2.7 V
2 kΩ
15 pF
2 × VCCO
0.15 V
1.1 V – 1.6 V
2 kΩ
15 pF
2 × VCCO
0.1 V
0.65 V – 0.95
V
20 kΩ
15 pF
2 × VCCO
0.1 V
3 V – 3.6 V
2 kΩ
15 pF
GND
0.3 V
1.65 V – 2.7 V
2 kΩ
15 pF
GND
0.15 V
1.1 V – 1.6 V
2 kΩ
15 pF
GND
0.1 V
0.65 V – 0.95
V
20 kΩ
15 pF
GND
0.1 V
VCCI(1)
VCCI(1)
Input A, B
Input A, B
VCCI / 2
VCCI / 2
500 ps/V ± 10 ns/V
0V
VOH(2)
VCCI / 2
Output B, A
VCCI / 2
VOL(2)
1.
2.
0V
VOH(2)
tpd
tpd
Output B, A
100 kHz
VCCI is the supply pin associated with the input port.
VOH and VOL are typical output voltage levels that occur with
specified RL, CL, and S1
1.
2.
Ensure Monotonic
Rising and Falling Edge
VOL(2)
VCCI is the supply pin associated with the input port.
VOH and VOL are typical output voltage levels that occur with
specified RL, CL, and S1
图 7. Input Transition Rise or Fall Rate
图 6. Propagation Delay
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VCCA
OE
VCCA / 2
VCCA / 2
GND
tdis
ten
VCCO(3)
Output(1)
VCCO / 2
VOL + VTP
VOL(4)
VOH(4)
VOH - VTP
Output(2)
VCCO / 2
GND
(1)
Output waveform on the condition that input is driven to a valid Logic Low.
(2)
Output waveform on the condition that input is driven to a valid Logic High.
(3)
VCCO is the supply pin associated with the output port.
(4)
VOH and VOL are typical output voltage levels with specified RL, CL, and S1.
图 8. Enable Time and Disable Time
20
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ZHCSJI7 – MARCH 2019
8 Detailed Description
8.1 Overview
The SN74AXCH4T245 is a 4-bit, dual-supply noninverting bidirectional voltage level translation device with bushold inputs. xAx pins and control pins (1DIR, 2DIR, 1OE, and 2OE) are reference to VCCA logic levels, and xBx
pins are referenced to VCCB logic levels. The A port is able to accept I/O voltages ranging from 0.65 V to 3.6 V,
while the B port can accept I/O voltages from 0.65 V to 3.6 V. A high on DIR allows data transmission from A to
B and a low on DIR allows data transmission from B to A when OE is set to low. When OE is set to high, both
xAx and xBx pins are in the high-impedance state. See Device Functional Modes for a summary of the operation
of the control logic.
8.2 Functional Block Diagram
One of Two Transceiver Pairs
VCCA
VCCB
xDIR
xOE
Bus-Hold
xB1
xA1
Bus-Hold
Bus-Hold
xB2
xA2
Bus-Hold
Note: Bus-hold circuits are only present for data inputs, not control inputs
8.3 Feature Description
8.3.1 Standard CMOS Inputs
Standard CMOS inputs are high impedance and are typically modeled as a resistor in parallel with the input
capacitance given in the Electrical Characteristics. The worst case resistance is calculated with the maximum
input voltage, given in the Absolute Maximum Ratings, and the maximum input leakage current, given in the
Electrical Characteristics, using Ohm's law (R = V ÷ I).
Signals applied to the inputs need to have fast edge rates, as defined by Δt/Δv in Recommended Operating
Conditions to avoid excessive current consumption and oscillations. If a slow or noisy input signal is required, a
device with a Schmitt-trigger input should be used to condition the input signal prior to the standard CMOS input.
8.3.2 Balanced High-Drive CMOS Push-Pull Outputs
A balanced output allows the device to sink and source similar currents. The high drive capability of this device
creates fast edges into light loads so routing and load conditions should be considered to prevent ringing.
Additionally, the outputs of this device are capable of driving larger currents than the device can sustain without
being damaged. The electrical and thermal limits defined in the Absolute Maximum Ratings must be followed at
all times.
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Feature Description (接
接下页)
8.3.3 Partial Power Down (Ioff)
The inputs and outputs for this device enter a high-impedance state when the device is powered down, inhibiting
current backflow into the device. The maximum leakage into or out of any input or output pin on the device is
specified by Ioff in the Electrical Characteristics.
8.3.4 VCC Isolation
The inputs and outputs for this device enter a high-impedance state when either supply is
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