INTEGRATED CIRCUITS DATA SHEET PCF8574 Remote 8-bit I/O expander for I2C-bus Product specification Supersedes data of September 1994 File under Integrated Circuits, IC12 1997 Apr 02
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus CONTENTS 1 FEATURES 2 GENERAL DESCRIPTION 3 ORDERING INFORMATION 4 BLOCK DIAGRAM 5 PINNING 6 CHARACTERISTICS OF THE I2C-BUS 6.1 6.2 6.3 6.4 Bit transfer Start and stop conditions System configuration Acknowledge 7 FUNCTIONAL DESCRIPTION 7.1 7.2 7.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus 1 FEATURES PCF8574 2 • Operating supply voltage 2.5 to 6 V GENERAL DESCRIPTION The PCF8574 is a silicon CMOS circuit. It provides general purpose remote I/O expansion for most microcontroller families via the two-line bidirectional bus (I2C). • Low standby current consumption of 10 µA maximum • I2C to parallel port expander The device consists of an 8-bit quasi-bidirectional port and an I2C-bus interface.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus 4 PCF8574 BLOCK DIAGRAM handbook, full pagewidth INT 13 INTERRUPT LOGIC A0 A1 A2 SCL SDA LP FILTER PCF8574 1 2 4 3 5 6 14 15 INPUT FILTER I 2 C BUS CONTROL 7 SHIFT REGISTER 8 BIT I/O PORT 9 10 11 12 WRITE pulse VDD V SS 16 8 READ pulse POWER-ON RESET MBD980 Fig.1 Block diagram (SOT38-1 and SOT162-1).
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus 5 PCF8574 PINNING PIN SYMBOL DESCRIPTION DIP16; SO16 SSOP20 A0 1 6 address input 0 A1 2 7 address input 1 A2 3 9 address input 2 P0 4 10 quasi-bidirectional I/O 0 P1 5 11 quasi-bidirectional I/O 1 P2 6 12 quasi-bidirectional I/O 2 P3 7 14 quasi-bidirectional I/O 3 VSS 8 15 supply ground P4 9 16 quasi-bidirectional I/O 4 P5 10 17 quasi-bidirectional I/O 5 P6 11 19 quasi-bidirec
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus 6 CHARACTERISTICS OF THE I2C-BUS PCF8574 6.2 The I2C-bus is for 2-way, 2-line communication between different ICs or modules. The two lines are a serial data line (SDA) and a serial clock line (SCL). Both lines must be connected to a positive supply via a pull-up resistor when connected to the output stages of a device. Data transfer may be initiated only when the bus is not busy.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus 6.4 PCF8574 transmitter. The device that acknowledges has to pull down the SDA line during the acknowledge clock pulse, so that the SDA line is stable LOW during the HIGH period of the acknowledge related clock pulse, set-up and hold times must be taken into account. Acknowledge The number of data bytes transferred between the start and the stop conditions from transmitter to receiver is not limited.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus 7 PCF8574 FUNCTIONAL DESCRIPTION VDD handbook, full pagewidth write pulse 100 µA data from shift register D Q FF P0 to P7 CI S power-on reset V SS D Q FF CI read pulse S to interrupt logic data to shift register MBD977 Fig.8 Simplified schematic diagram of each I/O. 7.1 Addressing For addressing see Figs 9, 10 and 11.
1997 Apr 02 9 DATA OUT FROM PORT WRITE TO PORT 3 4 5 6 1 0 0 A2 A1 slave address (PCF8574) 2 A0 7 R/W 0 8 DATA 1 t pv acknowledge from slave A DATA 1 VALID DATA 2 data to port t pv MBD974 DATA 2 VALID acknowledge from slave A Remote 8-bit I/O expander for I2C-bus Fig.10 WRITE mode (output).
1997 Apr 02 10 0 1 t iv start condition S 0 0 A2 A1 A0 t ph R/W 1 t ir DATA 2 acknowledge from slave A DATA 3 t ps t ir acknowledge from slave DATA 4 DATA 4 DATA 1 A data from port data from port P MBD975 stop condition 1 htdiwegap lluf ,koobdnah Fig.11 READ mode (input). Remote 8-bit I/O expander for I2C-bus A LOW-to-HIGH transition of SDA, while SCL is HIGH is defined as the stop condition (P). Transfer of data can be stopped at any moment by a stop condition.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus 7.2 • Interrupts which occur during the acknowledge clock pulse may be lost (or very short) due to the resetting of the interrupt during this pulse. Interrupt (see Figs 12 and 13) The PCF8574 provides an open drain output (INT) which can be fed to a corresponding input of the microcontroller. This gives these chips a type of master function which can initiate an action elsewhere in the system.
1997 Apr 02 12 P3 PULL-UP OUTPUT CURRENT P3 OUTPUT VOLTAGE SCL SDA 0 1 2 3 1 4 1 5 A2 6 A1 7 A0 8 R/W 0 acknowledge from slave A P3 1 I OHt A P3 0 data to port MBD971 I OH A P Remote 8-bit I/O expander for I2C-bus Fig.14 Transient pull-up current IOHt while P3 changes from LOW-to-HIGH and back to LOW.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus PCF8574 8 LIMITING VALUES In accordance with the Absolute Maximum Rating System (IEC 134). SYMBOL PARAMETER MIN. MAX. UNIT VDD supply voltage −0.5 +7.0 V VI input voltage VSS − 0.5 VDD + 0.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus SYMBOL PARAMETER PCF8574 CONDITIONS MIN. TYP. MAX. UNIT I/Os VIL LOW level input voltage −0.5 − +0.3VDD V VIH HIGH level input voltage 0.7VDD − VDD + 0.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus PCF8574 11 I2C-BUS TIMING CHARACTERISTICS SYMBOL PARAMETER MIN. TYP. MAX. UNIT I2C-BUS TIMING (see Fig.15; note 1) fSCL SCL clock frequency − − 100 kHz tSW tolerable spike width on bus − − 100 ns tBUF bus free time 4.7 − − µs tSU;STA START condition set-up time 4.7 − − µs tHD;STA START condition hold time 4.0 − − µs tLOW SCL LOW time 4.7 − − µs tHIGH SCL HIGH time 4.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus PCF8574 12 PACKAGE OUTLINES DIP16: plastic dual in-line package; 16 leads (300 mil); long body SOT38-1 ME seating plane D A2 A A1 L c e Z b1 w M (e 1) b MH 9 16 pin 1 index E 1 8 0 5 10 mm scale DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT A max. A1 min. A2 max. b b1 c D (1) E (1) e e1 L ME MH w Z (1) max. mm 4.7 0.51 3.7 1.40 1.14 0.53 0.38 0.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus PCF8574 SO16: plastic small outline package; 16 leads; body width 7.5 mm SOT162-1 D E A X c HE y v M A Z 9 16 Q A2 A (A 3) A1 pin 1 index θ Lp L 1 8 e detail X w M bp 0 5 10 mm scale DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT A max. A1 A2 A3 bp c D (1) E (1) e HE L Lp Q v w y mm 2.65 0.30 0.10 2.45 2.25 0.25 0.49 0.36 0.32 0.23 10.5 10.1 7.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus PCF8574 SSOP20: plastic shrink small outline package; 20 leads; body width 4.4 mm D SOT266-1 E A X c y HE v M A Z 11 20 Q A2 A (A 3) A1 pin 1 index θ Lp L 1 10 detail X w M bp e 0 2.5 5 mm scale DIMENSIONS (mm are the original dimensions) UNIT A max. A1 A2 A3 bp c D (1) E (1) e HE L Lp Q v w y Z (1) θ mm 1.5 0.15 0 1.4 1.2 0.25 0.32 0.20 0.20 0.13 6.6 6.4 4.5 4.3 0.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus Several techniques exist for reflowing; for example, thermal conduction by heated belt. Dwell times vary between 50 and 300 seconds depending on heating method. Typical reflow temperatures range from 215 to 250 °C. 13 SOLDERING 13.1 Introduction There is no soldering method that is ideal for all IC packages.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus PCF8574 14 DEFINITIONS Data sheet status Objective specification This data sheet contains target or goal specifications for product development. Preliminary specification This data sheet contains preliminary data; supplementary data may be published later. Product specification This data sheet contains final product specifications.
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus NOTES 1997 Apr 02 21 PCF8574
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus NOTES 1997 Apr 02 22 PCF8574
Philips Semiconductors Product specification Remote 8-bit I/O expander for I2C-bus NOTES 1997 Apr 02 23 PCF8574
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