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INTEGRATED CIRCUITS
DATA SHEET
PCF8574 Remote 8-bit I/O expander for I2C-bus
Product specification Supersedes data of 2002 Jul 29 2002 Nov 22
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
CONTENTS 1 2 3 4 5 5.1 5.2 6 6.1 6.2 6.3 6.4 7 7.1 7.2 7.3 8 9 10 11 12 13 13.1 13.2 13.2.1 13.2.2 13.3 13.3.1 13.3.2 13.3.3 13.4 14 15 16 17 FEATURES GENERAL DESCRIPTION ORDERING INFORMATION BLOCK DIAGRAM PINNING DIP16 and SO16 packages SSOP20 package CHARACTERISTICS OF THE I2C-BUS Bit transfer Start and stop conditions System configuration Acknowledge FUNCTIONAL DESCRIPTION Addressing Interrupt output Quasi-bidirectional I/Os LIMITING VALUES HANDLING DC CHARACTERISTICS I2C-BUS TIMING CHARACTERISTICS PACKAGE OUTLINES SOLDERING Introduction Through-hole mount packages Soldering by dipping or by solder wave Manual soldering Surface mount packages Reflow soldering Wave soldering Manual soldering Suitability of IC packages for wave, reflow and dipping soldering methods DATA SHEET STATUS DEFINITIONS DISCLAIMERS PURCHASE OF PHILIPS I2C COMPONENTS
PCF8574
2002 Nov 22
2
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
1 FEATURES
PCF8574
* Operating supply voltage 2.5 to 6 V * Low standby current consumption of 10 A maximum * I2C-bus to parallel port expander * Open-drain interrupt output * 8-bit remote I/O port for the I2C-bus * Compatible with most microcontrollers * Latched outputs with high current drive capability for directly driving LEDs * Address by 3 hardware address pins for use of up to 8 devices (up to 16 with PCF8574A) * DIP16, or space-saving SO16 or SSOP20 packages. 2 GENERAL DESCRIPTION The device consists of an 8-bit quasi-bidirectional port and an I2C-bus interface. The PCF8574 has a low current consumption and includes latched outputs with high current drive capability for directly driving LEDs. It also possesses an interrupt line (INT) which can be connected to the interrupt logic of the microcontroller. By sending an interrupt signal on this line, the remote I/O can inform the microcontroller if there is incoming data on its ports without having to communicate via the I2C-bus. This means that the PCF8574 can remain a simple slave device. The PCF8574 and PCF8574A versions differ only in their slave address as shown in Fig.10.
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-bus). 3 ORDERING INFORMATION
PACKAGE TYPE NUMBER NAME PCF8574P; PCF8574AP PCF8574T; PCF8574AT PCF8574TS; PCF8574ATS DIP16 SO16 SSOP20 DESCRIPTION plastic dual in-line package; 16 leads (300 mil) plastic small outline package; 16 leads; body width 7.5 mm plastic shrink small outline package; 20 leads; body width 4.4 mm VERSION SOT38-4 SOT162-1 SOT266-1
2002 Nov 22
3
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
4 BLOCK DIAGRAM
PCF8574
handbook, full pagewidth
INT A0 A1 A2 SCL SDA
13 1 2 3 14 15 INPUT FILTER
INTERRUPT LOGIC
LP FILTER
PCF8574
4 5 6 I 2 C BUS CONTROL 7 SHIFT REGISTER 8 BIT I/O PORT 9 10 11 12 P0 P1 P2 P3 P4 P5 P6 P7
WRITE pulse VDD V SS 16 8 POWER-ON RESET READ pulse
MBD980
Fig.1 Block diagram (pin numbers apply to DIP16 and SO16 packages).
2002 Nov 22
4
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
5 5.1 PINNING DIP16 and SO16 packages SYMBOL A0 A1 A2 P0 P1 P2 P3 VSS P4 P5 P6 P7 INT SCL SDA VDD PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 address input 0 address input 1 address input 2 quasi-bidirectional I/O 0 quasi-bidirectional I/O 1 quasi-bidirectional I/O 2 quasi-bidirectional I/O 3 supply ground quasi-bidirectional I/O 4 quasi-bidirectional I/O 5 quasi-bidirectional I/O 6 quasi-bidirectional I/O 7 interrupt output (active LOW) serial clock line serial data line supply voltage DESCRIPTION
PCF8574
handbook, halfpage
A0 1 A1 2 A2 3 P0 4
16 VDD 15 SDA 14 SCL
handbook, halfpage
A0 1 A1 2
16 VDD 15 SDA 14 SCL
A2 3 P0 4
PCF8574P 13 INT PCF8574AP 12 P7 P1 5
11 P6 10 P5 9
MBD979
P1 5 P2 6 P3 7 VSS 8
PCF8574T 13 INT PCF8574AT 12 P7
11 P6 10 P5 9
MCE001
P2 6 P3 7 VSS 8
P4
P4
Fig.2 Pin configuration (DIP16).
Fig.3 Pin configuration (SO16).
2002 Nov 22
5
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
5.2 SSOP20 package SYMBOL INT SCL n.c. SDA VDD A0 A1 n.c. A2 P0 P1 P2 n.c. P3 VSS P4 P5 n.c. P6 P7 PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 interrupt output (active LOW) serial clock line not connected serial data line supply voltage address input 0 address input 1 not connected address input 2 quasi-bidirectional I/O 0 quasi-bidirectional I/O 1 quasi-bidirectional I/O 2 not connected quasi-bidirectional I/O 3 supply ground quasi-bidirectional I/O 4 quasi-bidirectional I/O 5 not connected quasi-bidirectional I/O 6 quasi-bidirectional I/O 7 DESCRIPTION
PCF8574
handbook, halfpage
INT 1 SCL 2 n.c. 3 SDA 4 VDD 5
20 P7 19 P6 18 n.c. 17 P5 16 P4
PCF8574TS A0 6 PCF8574ATS 15 VSS
A1 7 14 P3 13 n.c. 12 P2 11 P1
MBD978
n.c. 8 A2 9
P0 10
Fig.4 Pin configuration (SSOP20).
2002 Nov 22
6
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
6 CHARACTERISTICS OF THE I2C-BUS 6.2 Start and stop conditions
PCF8574
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. 6.1 Bit transfer
Both data and clock lines remain HIGH when the bus is not busy. A HIGH-to-LOW transition of the data line, while the clock is HIGH is defined as the start condition (S). A LOW-to-HIGH transition of the data line while the clock is HIGH is defined as the stop condition (P) (see Fig.6). 6.3 System configuration
One data bit is transferred during each clock pulse. The data on the SDA line must remain stable during the HIGH period of the clock pulse as changes in the data line at this time will be interpreted as control signals (see Fig.5).
A device generating a message is a `transmitter', a device receiving is the `receiver'. The device that controls the message is the `master' and the devices which are controlled by the master are the `slaves' (see Fig.7).
handbook, full pagewidth
SDA
SCL data line stable; data valid change of data allowed
MBC621
Fig.5 Bit transfer.
handbook, full pagewidth
SDA
SDA
SCL S START condition P STOP condition
SCL
MBC622
Fig.6 Definition of start and stop conditions.
SDA SCL MASTER TRANSMITTER / RECEIVER SLAVE TRANSMITTER / RECEIVER MASTER TRANSMITTER / RECEIVER
MBA605
SLAVE RECEIVER
MASTER TRANSMITTER
Fig.7 System configuration.
2002 Nov 22
7
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
6.4 Acknowledge
PCF8574
of each byte that has been clocked out of the slave 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. A master receiver must signal an end of data to the transmitter by not generating an acknowledge on the last byte that has been clocked out of the slave. In this event the transmitter must leave the data line HIGH to enable the master to generate a stop condition.
The number of data bytes transferred between the start and the stop conditions from transmitter to receiver is not limited. Each byte of eight bits is followed by one acknowledge bit (see Fig.8). The acknowledge bit is a HIGH level put on the bus by the transmitter whereas the master generates an extra acknowledge related clock pulse. A slave receiver which is addressed must generate an acknowledge after the reception of each byte. Also a master must generate an acknowledge after the reception
handbook, full pagewidth
DATA OUTPUT BY TRANSMITTER not acknowledge DATA OUTPUT BY RECEIVER acknowledge SCL FROM MASTER S START condition clock pulse for acknowledgement
MBC602
1
2
8
9
Fig.8 Acknowledgment on the I2C-bus.
2002 Nov 22
8
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
7 FUNCTIONAL DESCRIPTION
PCF8574
handbook, full pagewidth
write pulse 100 A data from shift register D FF CI S power-on reset D FF read pulse data to shift register CI S Q Q
VDD
P0 to P7
V SS
to interrupt logic
MBD977
Fig.9 Simplified schematic diagram of each I/O.
7.1
Addressing
For addressing see Figs 10, 11 and 12.
handbook, full pagewidth
slave address
slave address
S
0
1
0
0
A2
A1
A0
0
A
S
0
1
1
1
A2
A1
A0
0
A
MBD973
a. PCF8574.
b. PCF8574A.
Fig.10 PCF8574 and PCF8574A slave addresses.
Each of the PCF8574's eight I/Os can be independently used as an input or output. Input data is transferred from the port to the microcontroller by the READ mode (see Fig.12). Output data is transmitted to the port by the WRITE mode (see Fig.11).
2002 Nov 22
9
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2002 Nov 22
SCL 1 2 3 4 5 6 7 8 slave address (PCF8574) SDA S 0 1 0 0 A2 A1 A0 0 A start condition WRITE TO PORT R/W acknowledge from slave
Philips Semiconductors
Remote 8-bit I/O expander for I2C-bus
data to port
data to port
DATA 1
A
DATA 2
A
acknowledge from slave
acknowledge from slave
10
DATA OUT FROM PORT
DATA 1 VALID t pv t pv
DATA 2 VALID
MBD974
Product specification
PCF8574
Fig.11 WRITE mode (output).
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slave address (PCF8574) data from port data from port SDA S 0 1 0 0 A2 A1 A0 1 A DATA 1 A DATA 4 1 P start condition READ FROM PORT R/W acknowledge from slave acknowledge from slave stop condition
Philips Semiconductors
Remote 8-bit I/O expander for I2C-bus
11
DATA INTO PORT t ph INT t iv t ir t ir
MBD975
DATA 2
DATA 3 t ps
DATA 4
Product specification
PCF8574
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. When this occurs, data present at the last acknowledge phase is valid (output mode). Input data is lost.
Fig.12 READ mode (input).
htdiwegap lluf ,koobdnah
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
7.2 Interrupt output
PCF8574
* Interrupts which occur during the acknowledge clock pulse may be lost (or very short) due to the resetting of the interrupt during this pulse. Each change of the I/Os after resetting will be detected and, after the next rising clock edge, will be transmitted as INT. Reading from or writing to another device does not affect the interrupt circuit. 7.3 Quasi-bidirectional I/Os
The PCF8574 provides an open-drain output (INT) which can be fed to a corresponding input of the microcontroller (see Figs 13 and 14). This gives these chips a type of master function which can initiate an action elsewhere in the system. An interrupt is generated by any rising or falling edge of the port inputs in the input mode. After time tiv the signal INT is valid. Resetting and reactivating the interrupt circuit is achieved when data on the port is changed to the original setting or data is read from or written to the port which has generated the interrupt. Resetting occurs as follows: * In the READ mode at the acknowledge bit after the rising edge of the SCL signal * In the WRITE mode at the acknowledge bit after the HIGH-to-LOW transition of the SCL signal
A quasi-bidirectional I/O can be used as an input or output without the use of a control signal for data direction (see Fig.15). At power-on the I/Os are HIGH. In this mode only a current source to VDD is active. An additional strong pull-up to VDD allows fast rising edges into heavily loaded outputs. These devices turn on when an output is written HIGH, and are switched off by the negative edge of SCL. The I/Os should be HIGH before being used as inputs.
handbook, full pagewidth
V DD MICROCONTROLLER INT
PCF8574 (1)
PCF8574 (2)
PCF8574 (16)
INT
INT
INT
MBD976
Fig.13 Application of multiple PCF8574s with interrupt.
handbook, full pagewidth
slave address (PCF8574)
data from port
SDA
S
0
1
0
0
A2
A1
A0
1
A
1
1
P
start condition
R/W
acknowledge P5 from slave
stop condition
SCL
1
2
3
4
5
6
7
8
DATA INTO P5
INT t iv t ir
MBD972
Fig.14 Interrupt generated by a change of input to I/O P5.
2002 Nov 22
12
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slave address (PCF8574A) data to port data to port SDA S 0 1 1 1 A2 A1 A0 0 A 1 A 0 A P start condition R/W acknowledge from slave P3 P3 SCL
Philips Semiconductors
Remote 8-bit I/O expander for I2C-bus
Fig.15 Transient pull-up current IOHt while P3 changes from LOW-to-HIGH and back to LOW.
handbook, full pagewidth
13
1
2
3
4
5
6
7
8
P3 OUTPUT VOLTAGE P3 PULL-UP OUTPUT CURRENT
I OHt
MBD971
I OH
Product specification
PCF8574
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
8 LIMITING VALUES In accordance with the Absolute Maximum Rating System (IEC 60134). SYMBOL VDD VI II IO IDD ISS Ptot PO Tstg Tamb 9 supply voltage input voltage DC input current DC output current supply current supply current total power dissipation power dissipation per output storage temperature ambient temperature PARAMETER -0.5 VSS - 0.5 - - - - - - -65 -40 MIN. MAX. +7.0 VDD + 0.5 20 25 100 100 400 100 +150 +85
PCF8574
UNIT V V mA mA mA mA mW mW C C
HANDLING
Inputs and outputs are protected against electrostatic discharge in normal handling. However it is good practice to take normal precautions appropriate to handling MOS devices (see "Handling MOS devices"). 10 DC CHARACTERISTICS VDD = 2.5 to 6 V; VSS = 0 V; Tamb = -40 to +85 C; unless otherwise specified. SYMBOL Supply VDD IDD supply voltage supply current 2.5 operating mode; VDD = 6 V; - no load; VI = VDD or VSS; fSCL = 100 kHz standby mode; VDD = 6 V; no load; VI = VDD or VSS VDD = 6 V; no load; VI = VDD or VSS; note 1 - - - 40 6.0 100 V A PARAMETER CONDITIONS MIN. TYP. MAX. UNIT
Istb VPOR
standby current Power-on reset voltage
2.5 1.3
10 2.4
A V
Input SCL; input/output SDA VIL VIH IOL IL Ci LOW level input voltage HIGH level input voltage LOW level output current leakage current input capacitance VOL = 0.4 V VI = VDD or VSS VI = VSS -0.5 0.7VDD 3 -1 - - - - - - +0.3VDD VDD + 0.5 - +1 7 V V mA A pF
2002 Nov 22
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Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
SYMBOL I/Os VIL VIH IIHL(max)
PARAMETER
CONDITIONS
MIN. -0.5 0.7VDD - - -
TYP.
MAX.
UNIT
LOW level input voltage HIGH level input voltage maximum allowed input current through protection diode LOW level output current HIGH level output current transient pull-up current VI VDD or VI VSS
+0.3VDD VDD + 0.5 400
V V A
-
IOL IOH IOHt
VOL = 1 V; VDD = 5 V VOH = VSS HIGH during acknowledge (see Fig.15); VOH = VSS; VDD = 2.5 V
10 30 -
25 - -1
- 300 -
mA A mA
Ci Co
input capacitance output capacitance
- - - 0 4
- - - - - - - - - - - -
10 10
pF pF s s s mA A s s V V nA
Port timing; CL 100 pF (see Figs 11 and 12) tpv tsu th IOL IL tiv tir VIL VIH ILI Note 1. The Power-on reset circuit resets the I2C-bus logic at VDD < VPOR and sets all I/Os to logic 1 (with current source to VDD). output data valid input data set-up time input data hold time 4 - - - +1
Interrupt INT (see Fig.14) LOW level output current leakage current VOL = 0.4 V VI = VDD or VSS 1.6 -1 - - -0.5 0.7VDD pin at VDD or VSS -250
TIMING; CL 100 pF input data valid time reset delay time 4 4
Select inputs A0 to A2 LOW level input voltage HIGH level input voltage input leakage current +0.3VDD VDD + 0.5 +250
2002 Nov 22
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Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
11 I2C-BUS TIMING CHARACTERISTICS SYMBOL PARAMETER MIN. TYP.
PCF8574
MAX.
UNIT
I2C-bus timing (see Fig.16; note 1) fSCL tSW tBUF tSU;STA tHD;STA tLOW tHIGH tr tf tSU;DAT tHD;DAT tVD;DAT tSU;STO Note 1. All the timing values are valid within the operating supply voltage and ambient temperature range and refer to VIL and VIH with an input voltage swing of VSS to VDD. SCL clock frequency tolerable spike width on bus bus free time START condition set-up time START condition hold time SCL LOW time SCL HIGH time SCL and SDA rise time SCL and SDA fall time data set-up time data hold time SCL LOW to data out valid STOP condition set-up time - - 4.7 4.7 4.0 4.7 4.0 - - 250 0 - 4.0 - - - - - - - - - - - - - 100 100 - - - - - 1.0 0.3 - - 3.4 - kHz ns s s s s s s s ns ns s s
handbook, full pagewidth
PROTOCOL
START CONDITION (S)
BIT 7 MSB (A7)
BIT 6 (A6)
BIT 0 LSB (R/W)
ACKNOWLEDGE (A)
STOP CONDITION (P)
t SU;STA
t LOW
t HIGH
1 / f SCL
SCL
t
BUF
tr
tf
SDA
t HD;STA
t
SU;DAT
t
HD;DAT
t
VD;DAT
MBD820
t SU;STO
Fig.16 I2C-bus timing diagram.
2002 Nov 22
16
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
12 PACKAGE OUTLINES DIP16: plastic dual in-line package; 16 leads (300 mil)
PCF8574
SOT38-4
D seating plane
ME
A2
A
L
A1
c Z e b1 b 16 9 b2 MH wM (e 1)
pin 1 index E
1
8
0
5 scale
10 mm
DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT mm inches A max. 4.2 0.17 A1 min. 0.51 0.020 A2 max. 3.2 0.13 b 1.73 1.30 0.068 0.051 b1 0.53 0.38 0.021 0.015 b2 1.25 0.85 0.049 0.033 c 0.36 0.23 0.014 0.009 D (1) 19.50 18.55 0.77 0.73 E (1) 6.48 6.20 0.26 0.24 e 2.54 0.10 e1 7.62 0.30 L 3.60 3.05 0.14 0.12 ME 8.25 7.80 0.32 0.31 MH 10.0 8.3 0.39 0.33 w 0.254 0.01 Z (1) max. 0.76 0.030
Note 1. Plastic or metal protrusions of 0.25 mm maximum per side are not included. OUTLINE VERSION SOT38-4 REFERENCES IEC JEDEC EIAJ EUROPEAN PROJECTION
ISSUE DATE 92-11-17 95-01-14
2002 Nov 22
17
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 y HE vMA
Z 16 9
Q A2 A1 pin 1 index Lp L 1 e bp 8 wM detail X (A 3) A
0
5 scale
10 mm
DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT mm inches A max. 2.65 0.10 A1 0.30 0.10 A2 2.45 2.25 A3 0.25 0.01 bp 0.49 0.36 c 0.32 0.23 D (1) 10.5 10.1 0.41 0.40 E (1) 7.6 7.4 0.30 0.29 e 1.27 0.050 HE 10.65 10.00 L 1.4 Lp 1.1 0.4 Q 1.1 1.0 0.043 0.039 v 0.25 0.01 w 0.25 0.01 y 0.1 0.004 Z
(1)
0.9 0.4 0.035 0.016
0.012 0.096 0.004 0.089
0.019 0.013 0.014 0.009
0.419 0.043 0.055 0.394 0.016
8o 0o
Note 1. Plastic or metal protrusions of 0.15 mm maximum per side are not included. OUTLINE VERSION SOT162-1 REFERENCES IEC 075E03 JEDEC MS-013 EIAJ EUROPEAN PROJECTION
ISSUE DATE 97-05-22 99-12-27
2002 Nov 22
18
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
SOT266-1
D
E
A X
c y HE vM A
Z
20
11
Q A2 pin 1 index A1 (A 3) Lp L A
1
e bp
10
detail X wM
0
2.5 scale
5 mm
DIMENSIONS (mm are the original dimensions) UNIT mm A max. 1.5 A1 0.15 0 A2 1.4 1.2 A3 0.25 bp 0.32 0.20 c 0.20 0.13 D (1) 6.6 6.4 E (1) 4.5 4.3 e 0.65 HE 6.6 6.2 L 1.0 Lp 0.75 0.45 Q 0.65 0.45 v 0.2 w 0.13 y 0.1 Z (1) 0.48 0.18 10 0o
o
Note 1. Plastic or metal protrusions of 0.20 mm maximum per side are not included. OUTLINE VERSION SOT266-1 REFERENCES IEC JEDEC MO-152 EIAJ EUROPEAN PROJECTION
ISSUE DATE 95-02-22 99-12-27
2002 Nov 22
19
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
13 SOLDERING 13.1 Introduction
PCF8574
Typical reflow peak temperatures range from 215 to 250 C. The top-surface temperature of the packages should preferable be kept below 220 C for thick/large packages, and below 235 C for small/thin packages. 13.3.2 WAVE SOLDERING
This text gives a very brief insight to a complex technology. A more in-depth account of soldering ICs can be found in our "Data Handbook IC26; Integrated Circuit Packages" (document order number 9398 652 90011). There is no soldering method that is ideal for all IC packages. Wave soldering is often preferred when through-hole and surface mount components are mixed on one printed-circuit board. Wave soldering can still be used for certain surface mount ICs, but it is not suitable for fine pitch SMDs. In these situations reflow soldering is recommended. 13.2 13.2.1 Through-hole mount packages SOLDERING BY DIPPING OR BY SOLDER WAVE
Conventional single wave soldering is not recommended for surface mount devices (SMDs) or printed-circuit boards with a high component density, as solder bridging and non-wetting can present major problems. To overcome these problems the double-wave soldering method was specifically developed. If wave soldering is used the following conditions must be observed for optimal results: * Use a double-wave soldering method comprising a turbulent wave with high upward pressure followed by a smooth laminar wave. * For packages with leads on two sides and a pitch (e): - larger than or equal to 1.27 mm, the footprint longitudinal axis is preferred to be parallel to the transport direction of the printed-circuit board; - smaller than 1.27 mm, the footprint longitudinal axis must be parallel to the transport direction of the printed-circuit board. The footprint must incorporate solder thieves at the downstream end. * For packages with leads on four sides, the footprint must be placed at a 45 angle to the transport direction of the printed-circuit board. The footprint must incorporate solder thieves downstream and at the side corners. During placement and before soldering, the package must be fixed with a droplet of adhesive. The adhesive can be applied by screen printing, pin transfer or syringe dispensing. The package can be soldered after the adhesive is cured. Typical dwell time is 4 seconds at 250 C. A mildly-activated flux will eliminate the need for removal of corrosive residues in most applications. 13.3.3 MANUAL SOLDERING
The maximum permissible temperature of the solder is 260 C; solder at this temperature must not be in contact with the joints for more than 5 seconds. The total contact time of successive solder waves must not exceed 5 seconds. The device may be mounted up to the seating plane, but the temperature of the plastic body must not exceed the specified maximum storage temperature (Tstg(max)). If the printed-circuit board has been pre-heated, forced cooling may be necessary immediately after soldering to keep the temperature within the permissible limit. 13.2.2 MANUAL SOLDERING
Apply the soldering iron (24 V or less) to the lead(s) of the package, either below the seating plane or not more than 2 mm above it. If the temperature of the soldering iron bit is less than 300 C it may remain in contact for up to 10 seconds. If the bit temperature is between 300 and 400 C, contact may be up to 5 seconds. 13.3 13.3.1 Surface mount packages REFLOW SOLDERING
Reflow soldering requires solder paste (a suspension of fine solder particles, flux and binding agent) to be applied to the printed-circuit board by screen printing, stencilling or pressure-syringe dispensing before package placement. Several methods exist for reflowing; for example, convection or convection/infrared heating in a conveyor type oven. Throughput times (preheating, soldering and cooling) vary between 100 and 200 seconds depending on heating method.
Fix the component by first soldering two diagonally-opposite end leads. Use a low voltage (24 V or less) soldering iron applied to the flat part of the lead. Contact time must be limited to 10 seconds at up to 300 C. When using a dedicated tool, all other leads can be soldered in one operation within 2 to 5 seconds between 270 and 320 C. 20
2002 Nov 22
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
13.4 Suitability of IC packages for wave, reflow and dipping soldering methods MOUNTING PACKAGE(1) suitable(3) not suitable(4) suitable not recommended(5)(6) not recommended(7)
PCF8574
SOLDERING METHOD WAVE REFLOW(2) DIPPING - suitable suitable suitable suitable suitable suitable - - - - -
Through-hole mount DBS, DIP, HDIP, SDIP, SIL Surface mount HBCC, HBGA, HLQFP, HSQFP, HSOP, HTQFP, HTSSOP, HVQFN, HVSON, SMS PLCC(5), SO, SOJ LQFP, QFP, TQFP SSOP, TSSOP, VSO Notes
BGA, LBGA, LFBGA, SQFP, TFBGA, VFBGA not suitable
1. For more detailed information on the BGA packages refer to the "(LF)BGA Application Note" (AN01026); order a copy from your Philips Semiconductors sales office. 2. All surface mount (SMD) packages are moisture sensitive. Depending upon the moisture content, the maximum temperature (with respect to time) and body size of the package, there is a risk that internal or external package cracks may occur due to vaporization of the moisture in them (the so called popcorn effect). For details, refer to the Drypack information in the "Data Handbook IC26; Integrated Circuit Packages; Section: Packing Methods". 3. For SDIP packages, the longitudinal axis must be parallel to the transport direction of the printed-circuit board. 4. These packages are not suitable for wave soldering. On versions with the heatsink on the bottom side, the solder cannot penetrate between the printed-circuit board and the heatsink. On versions with the heatsink on the top side, the solder might be deposited on the heatsink surface. 5. If wave soldering is considered, then the package must be placed at a 45 angle to the solder wave direction. The package footprint must incorporate solder thieves downstream and at the side corners. 6. Wave soldering is suitable for LQFP, QFP and TQFP packages with a pitch (e) larger than 0.8 mm; it is definitely not suitable for packages with a pitch (e) equal to or smaller than 0.65 mm. 7. Wave soldering is suitable for SSOP and TSSOP packages with a pitch (e) equal to or larger than 0.65 mm; it is definitely not suitable for packages with a pitch (e) equal to or smaller than 0.5 mm.
2002 Nov 22
21
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
14 DATA SHEET STATUS LEVEL I DATA SHEET STATUS(1) Objective data PRODUCT STATUS(2)(3) Development DEFINITION
PCF8574
This data sheet contains data from the objective specification for product development. Philips Semiconductors reserves the right to change the specification in any manner without notice. This data sheet contains data from the preliminary specification. Supplementary data will be published at a later date. Philips Semiconductors reserves the right to change the specification without notice, in order to improve the design and supply the best possible product. This data sheet contains data from the product specification. Philips Semiconductors reserves the right to make changes at any time in order to improve the design, manufacturing and supply. Relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN).
II
Preliminary data Qualification
III
Product data
Production
Notes 1. Please consult the most recently issued data sheet before initiating or completing a design. 2. The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL http://www.semiconductors.philips.com. 3. For data sheets describing multiple type numbers, the highest-level product status determines the data sheet status. 15 DEFINITIONS Short-form specification The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see the relevant data sheet or data handbook. Limiting values definition Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification. 16 DISCLAIMERS Life support applications These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application. Right to make changes Philips Semiconductors reserves the right to make changes in the products including circuits, standard cells, and/or software described or contained herein in order to improve design and/or performance. When the product is in full production (status `Production'), relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no licence or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified.
2002 Nov 22
22
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
17 PURCHASE OF PHILIPS I2C COMPONENTS
PCF8574
Purchase of Philips I2C components conveys a license under the Philips' I2C patent to use the components in the I2C system provided the system conforms to the I2C specification defined by Philips. This specification can be ordered using the code 9398 393 40011.
2002 Nov 22
23
Philips Semiconductors - a worldwide company
Contact information For additional information please visit http://www.semiconductors.philips.com. Fax: +31 40 27 24825 For sales offices addresses send e-mail to: sales.addresses@www.semiconductors.philips.com.
(c) Koninklijke Philips Electronics N.V. 2002
SCA74
All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent- or other industrial or intellectual property rights.
Printed in The Netherlands
403512/04/pp24
Date of release: 2002
Nov 22
Document order number:
9397 750 10462

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