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  • 用于 I2C 总线的 PCF8574A 远程 8 位 I/O 扩展器

    • ZHCSOM7H July   2001  – September 2024 PCF8574A

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  • 用于 I2C 总线的 PCF8574A 远程 8 位 I/O 扩展器
  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 I2C Interface Timing Requirements
    7. 5.7 Switching Characteristics
    8. 5.8 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
      1. 7.2.1 Simplified Block Diagram of Device
      2. 7.2.2 Simplified Schematic Diagram of Each P-Port Input/Output
    3. 7.3 Feature Description
      1. 7.3.1 I2C Interface
      2. 7.3.2 Interface Definition
      3. 7.3.3 Address Reference
    4. 7.4 Device Functional Modes
  9. 8 Application Information Disclaimer
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Minimizing ICC When I/Os Control LEDs
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power-On Reset Requirements
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Glossary
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 支持资源
    4. 9.4 Trademarks
    5. 9.5 静电放电警告
    6. 9.6 术语表
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
  13. 重要声明
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Data Sheet

用于 I2C 总线的 PCF8574A 远程 8 位 I/O 扩展器

本资源的原文使用英文撰写。 为方便起见，TI 提供了译文；由于翻译过程中可能使用了自动化工具，TI 不保证译文的准确性。 为确认准确性，请务必访问 ti.com 参考最新的英文版本（控制文档）。

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1 特性

  • 低待机流耗，最大值为 10μA
  • I2C 至并行端口扩展器
  • 开漏中断输出
  • 兼容大多数微控制器
  • 具有高电流驱动能力的锁存输出，用于直接驱动 LED
  • 闩锁性能超过 100mA，符合 JESD 78 II 类规范的要求

2 应用

  • 电信方舱：滤波器单元
  • 服务器
  • 路由器（电信交换设备）
  • 个人计算机
  • 个人电子产品
  • 工业自动化
  • 采用 GPIO 受限处理器的产品

3 说明

这款面向两线制双向总线 (I2C) 的 8 位输入/输出 (I/O) 扩展器设计为在 2.5V 至 6V VCC 下运行。

PCF8574A 器件通过 I2C 接口 [串行时钟 (SCL)、串行数据 (SDA)] 为大多数微控制器系列提供通用远程 I/O 扩展。

该器件具有一个 8 位准双向 I/O 端口 (P0–P7)，其中包括具有高电流驱动能力的锁存输出，用于直接驱动 LED。每个准双向 I/O 都可以用作输入或输出（无需使用数据方向控制信号）。在上电时，这些 I/O 处于高电平。在该模式下，仅有一个连接到 VCC 的电流源处于活动状态。

器件信息
器件型号封装(1)本体尺寸（标称值）
PCF8574AVQFN (20)4.50mm × 3.50mm
PDIP (16)19.30mm × 6.35mm
SOIC (16)10.30mm × 7.50mm
TSSOP (20)6.50mm × 4.40mm
TVSOP (20)5.00mm × 4.40mm
(1) 如需了解所有可用封装，请参阅数据表末尾的可订购产品附录。
PCF8574A

4 Pin Configuration and Functions

PCF8574A DW or N Package16 PinsTop ViewFigure 4-1 DW or N Package16 PinsTop View
PCF8574A RGY Package20 PinsTop ViewFigure 4-2 RGY Package20 PinsTop View
PCF8574A DGV or PW Package20 PinsTop View Figure 4-3 DGV or PW Package20 PinsTop View
Table 4-1 Pin Functions
PIN TYPE DESCRIPTION
NAME RGY DGV or PW DW or N
A[0..2] 6, 7, 9 6, 7, 9 1, 2, 3 I Address inputs 0 through 2. Connect directly to VCC or ground. Pullup resistors are not needed.
GND 15 15 8 — Ground
INT 1 1 13 O Interrupt output. Connect to VCC through a pullup resistor.
NC 3, 8, 13, 18 3, 8, 13, 18 - — Do not connect
P[0..7] 10, 11, 12, 14, 16, 17, 19, 20 10, 11, 12, 14, 16, 17, 19, 20 4, 5, 6, 7, 9, 10, 11, 12 I/O P-port input/output. Push-pull design structure.
SCL 2 2 14 I Serial clock line. Connect to VCC through a pullup resistor
SDA 4 4 15 I/O Serial data line. Connect to VCC through a pullup resistor.
VCC 5 5 16 — Voltage supply

5 Specifications

5.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)
MIN MAX UNIT
VCC Supply voltage range –0.5 6.5 V
VI Input voltage range(2) –0.5 VCC + 0.5 V
VO Output voltage range(2) –0.5 VCC + 0.5 V
IIK Input clamp current VI < 0 –20 mA
IOK Output clamp current VO < 0 –20 mA
IOK Input/output clamp current VO < 0 or VO > VCC ±400 μA
IOL Continuous output low current VO = 0 to VCC 50 mA
IOH Continuous output high current VO = 0 to VCC –4 mA
Continuous current through VCC or GND ±100 mA
TJ Junction temperature 150 °C
Tstg Storage temperature range –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Section 5.3 is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) The input negative-voltage and output voltage ratings may be exceeded if the input and output current ratings are observed.

5.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins  (1) 1000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101, all pins (2) 1500
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

5.3 Recommended Operating Conditions

MIN MAX UNIT
VCC Supply voltage 2.5 6 V
VIH High-level input voltage 0.7 × VCC VCC + 0.5 V
VIL Low-level input voltage –0.5 0.3 × VCC V
IOH High-level output current –1 mA
IOL Low-level output current 25 mA
TA Operating free-air temperature –40 85 °C

5.4 Thermal Information

THERMAL METRIC(1) PCF8574A UNIT
DGV DW N PW RGY
20 PINS 16 PINS 16 PINS 20 PINS 20 PINS
RθJA Junction-to-ambient thermal resistance 112.2 76.7 48.3 94.8 52.2 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 35.2 45.1 35.6 40.2 50.6 °C/W
RθJB Junction-to-board thermal resistance 53.4 45.8 28.2 58.5 29.2 °C/W
ψJT Junction-to-top characterization parameter 1.8 17.2 20.5 2.8 3.3 °C/W
ψJB Junction-to-board characterization parameter 52.8 45.2 28.1 58.0 29.1 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance n/a n/a n/a n/a 16.0 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC package thermal metrics application report.

5.5 Electrical Characteristics

over recommended operating free-air temperature range (unless otherwise noted)
TEST CONDITIONS VCC MIN TYP(1) MAX UNIT
VIK Input diode clamp voltage II = –18 mA 2.5 V to 6 V –1.2 V
VPOR Power-on reset voltage VI = VCC or GND, IO = 0 6 V 1.3 2.4 V
IOH P port   VO = GND 2.5 V to 6 V -310 -30 μA
IOHT P port transient pullup current High during acknowledge, VOH = GND 2.5 V –1 mA
IOL SDA   VO = 0.4 V 2.5 V to 6 V 3 mA
P port VO = 1 V 5 V 10 25
INT VO = 0.4 V 2.5 V to 6 V 1.6
II SCL, SDA VI = VCC or GND 2.5 V to 6 V ±5 μA
INT ±5
A0, A1, A2 ±5
IIHL P port   -250mV < Vi < GND 2.5 V to 6 V ±400 μA
ICC Operating mode VI = VCC or GND, IO = 0, fSCL = 100 kHz 6 V 40 100 μA
Standby mode VI = VCC or GND, IO = 0 2.5 10
Ci SCL VI = VCC or GND 2.5 V to 6 V 1.5 7 pF
Cio SDA VIO = VCC or GND 2.5 V to 6 V 3 7 pF
P port 4 10
(1) All typical values are at VCC = 5 V, TA = 25°C.

5.6 I2C Interface Timing Requirements

over recommended operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
fscl I2C clock frequency 100 kHz
tsch I2C clock high time 4 μs
tscl I2C clock low time 4.7 μs
tsp I2C spike time   70 ns
tsds I2C serial data setup time 250 ns
tsdh I2C serial data hold time 0 ns
ticr I2C input rise time 1 μs
ticf I2C input fall time 0.3 μs
tocf I2C output fall time (10-pF to 400-pF bus) 300 ns
tbuf I2C bus free time between stop and start 4.7 μs
tsts I2C start or repeated start condition setup 4.7 μs
tsth I2C start or repeated start condition hold 4 μs
tsps I2C stop condition setup 4 μs
tvd Valid data time SCL low to SDA output valid 3.4 μs
Cb I2C bus capacitive load 400 pF

5.7 Switching Characteristics

over recommended operating free-air temperature range, CL ≤ 100 pF (unless otherwise noted)
PARAMETER FROM (INPUT) TO (OUTPUT) MIN MAX UNIT
tpv Output data valid SCL P port 4 μs
tsu Input data setup time P port SCL 0 μs
th Input data hold time P port SCL 4 μs
tiv Interrupt valid time P port INT 4 μs
tir Interrupt reset delay time SCL INT 4 μs

 
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