PCF8574ATS [NXP]
Remote 8-bit I/O expander for I2C-bus; 远程8位I / O扩展器I2C总线
| 型号： | PCF8574ATS |
| 厂家： | 
NXP |
| 描述： | Remote 8-bit I/O expander for I2C-bus |
| 文件： | 总24页 (文件大小：134K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
INTEGRATED CIRCUITS
DATA SHEET
PCF8574
Remote 8-bit I/O expander for
I2C-bus
Product specification
2002 Nov 22
Supersedes data of 2002 Jul 29
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
CONTENTS
1
2
3
4
5
FEATURES
GENERAL DESCRIPTION
ORDERING INFORMATION
BLOCK DIAGRAM
PINNING
5.1
5.2
DIP16 and SO16 packages
SSOP20 package
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
7.3
Addressing
Interrupt output
Quasi-bidirectional I/Os
8
LIMITING VALUES
9
HANDLING
10
11
12
13
DC CHARACTERISTICS
I2C-BUS TIMING CHARACTERISTICS
PACKAGE OUTLINES
SOLDERING
13.1
Introduction
13.2
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
13.2.1
13.2.2
13.3
13.3.1
13.3.2
13.3.3
13.4
14
15
16
17
DATA SHEET STATUS
DEFINITIONS
DISCLAIMERS
PURCHASE OF PHILIPS I2C COMPONENTS
2002 Nov 22
2
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
1
FEATURES
• Operating supply voltage 2.5 to 6 V
• Low standby current consumption of 10 µA maximum
• I2C-bus to parallel port expander
• Open-drain interrupt output
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.
• 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 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
DESCRIPTION
VERSION
PCF8574P;
PCF8574AP
DIP16
plastic dual in-line package; 16 leads (300 mil)
SOT38-4
PCF8574T;
PCF8574AT
SO16
plastic small outline package; 16 leads; body width 7.5 mm
SOT162-1
SOT266-1
PCF8574TS;
PCF8574ATS
SSOP20
plastic shrink small outline package; 20 leads; body width 4.4 mm
2002 Nov 22
3
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
4
BLOCK DIAGRAM
13
INTERRUPT
LOGIC
INT
LP FILTER
1
2
3
PCF8574
A0
A1
4
5
P0
P1
P2
P3
P4
P5
P6
P7
A2
6
14
15
SCL
SDA
2
7
INPUT
FILTER
I C BUS
SHIFT
REGISTER
I/O
PORT
CONTROL
8 BIT
9
10
11
12
WRITE pulse
READ pulse
16
8
V
DD
POWER-ON
RESET
V
SS
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
PCF8574
5
PINNING
DIP16 and SO16 packages
5.1
SYMBOL
PIN
DESCRIPTION
A0
A1
A2
P0
P1
P2
P3
1
2
address input 0
address input 1
3
address input 2
4
quasi-bidirectional I/O 0
quasi-bidirectional I/O 1
quasi-bidirectional I/O 2
quasi-bidirectional I/O 3
supply ground
5
6
7
VSS
P4
8
9
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
P5
10
11
12
13
14
15
16
P6
P7
INT
SCL
SDA
VDD
serial data line
supply voltage
handbook, halfpage
handbook, halfpage
V
1
2
3
4
5
6
7
8
16
15
A0
DD
V
1
2
3
4
5
6
7
8
16
15
A0
DD
A1
A2
SDA
A1
A2
SDA
14 SCL
14 SCL
13
P0
P1
P2
P3
INT
13
P0
P1
P2
P3
SS
INT
PCF8574P
PCF8574AP
PCF8574T
PCF8574AT
12 P7
11 P6
12
P7
11 P6
10
9
P5
P4
10
9
P5
P4
V
V
SS
MCE001
MBD979
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
PCF8574
5.2
SSOP20 package
SYMBOL
INT
PIN
DESCRIPTION
1
2
interrupt output (active LOW)
serial clock line
SCL
n.c.
SDA
VDD
A0
3
not connected
4
serial data line
5
supply voltage
6
address input 0
A1
7
address input 1
n.c.
A2
8
not connected
9
address input 2
P0
10
11
12
13
14
15
16
17
18
19
20
quasi-bidirectional I/O 0
quasi-bidirectional I/O 1
quasi-bidirectional I/O 2
not connected
P1
P2
n.c.
P3
quasi-bidirectional I/O 3
supply ground
VSS
P4
quasi-bidirectional I/O 4
quasi-bidirectional I/O 5
not connected
P5
n.c.
P6
quasi-bidirectional I/O 6
quasi-bidirectional I/O 7
P7
handbook, halfpage
INT
SCL
n.c.
P7
P6
1
2
20
19
3
18 n.c.
17
4
SDA
P5
16 P4
V
5
DD
PCF8574TS
PCF8574ATS
V
A0
A1
6
15
14
SS
P3
7
n.c.
A2
8
13 n.c.
12 P2
9
P0
P1
11
10
MBD978
Fig.4 Pin configuration (SSOP20).
2002 Nov 22
6
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
CHARACTERISTICS OF THE I2C-BUS
6.2
Start and stop conditions
6
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.
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
6.1
Bit transfer
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).
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).
SDA
SCL
data line
stable;
data valid
change
of data
allowed
MBC621
Fig.5 Bit transfer.
SDA
SCL
SDA
SCL
S
P
STOP condition
START condition
MBC622
Fig.6 Definition of start and stop conditions.
SDA
SCL
MASTER
TRANSMITTER /
RECEIVER
SLAVE
TRANSMITTER /
RECEIVER
MASTER
TRANSMITTER /
RECEIVER
SLAVE
RECEIVER
MASTER
TRANSMITTER
MBA605
Fig.7 System configuration.
7
2002 Nov 22
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
6.4
Acknowledge
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.
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 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.
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
DATA OUTPUT
BY TRANSMITTER
not acknowledge
acknowledge
DATA OUTPUT
BY RECEIVER
SCL FROM
1
2
8
9
MASTER
S
clock pulse for
acknowledgement
START
condition
MBC602
Fig.8 Acknowledgment on the I2C-bus.
2002 Nov 22
8
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
7
FUNCTIONAL DESCRIPTION
V
DD
write pulse
100
µA
data from
shift register
D
C
Q
FF
P0 to P7
I
S
power-on
reset
V
SS
D
C
Q
FF
I
read pulse
S
to interrupt
logic
data to
shift register
MBD977
Fig.9 Simplified schematic diagram of each I/O.
7.1
Addressing
For addressing see Figs 10, 11 and 12.
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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g
SCL
SDA
1
0
2
3
4
5
6
7
8
0
slave address (PCF8574)
data to port
DATA 1
data to port
DATA 2
S
1
0
0
A2 A1 A0
A
A
A
start condition
R/W acknowledge
from slave
acknowledge
from slave
acknowledge
from slave
WRITE TO
PORT
DATA OUT
FROM PORT
DATA 1 VALID
DATA 2 VALID
t
t
pv
pv
MBD974
Fig.11 WRITE mode (output).
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slave address (PCF8574)
data from port
DATA 1
data from port
DATA 4
SDA
S
0
1
0
0
A2 A1 A0
1
A
A
1
P
start condition
R/W acknowledge
from slave
acknowledge
from slave
stop
condition
READ FROM
PORT
DATA INTO
PORT
DATA 2
DATA 3
DATA 4
t
t
ps
ph
INT
MBD975
t
t
t
ir
ir
iv
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).
ahdnbok,uflapegwidt
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
7.2
Interrupt output
• Interrupts which occur during the acknowledge clock
pulse may be lost (or very short) due to the resetting of
the interrupt during this pulse.
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.
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.
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.
7.3
Quasi-bidirectional I/Os
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.
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
PCF8574
PCF8574
(2)
PCF8574
(16)
V
(1)
DD
MICROCONTROLLER
INT
INT
INT
INT
MBD976
Fig.13 Application of multiple PCF8574s with interrupt.
slave address (PCF8574)
data from port
SDA
SCL
S
0
1
0
0
A2 A1 A0
1
A
1
1
P
P5
stop
condition
start condition
R/W acknowledge
from slave
1
2
3
4
5
6
7
8
DATA INTO
P5
INT
MBD972
t
t
iv
ir
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
SCL
S
0
1
1
1
A2 A1 A0
0
A
1
A
0
A
P
P3
P3
start condition
R/W acknowledge
from slave
1
2
3
4
5
6
7
8
P3
OUTPUT
VOLTAGE
P3
PULL-UP
OUTPUT
CURRENT
I
I
OH
OHt
MBD971
Fig.15 Transient pull-up current IOHt while P3 changes from LOW-to-HIGH and back to LOW.
ahdnbok,uflapegwidt
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 60134).
SYMBOL PARAMETER
VDD
MIN.
MAX.
UNIT
supply voltage
−0.5
+7.0
VDD + 0.5
±20
V
VI
input voltage
V
−
−
−
−
−
−
SS − 0.5
V
II
DC input current
DC output current
supply current
mA
mA
mA
mA
mW
mW
°C
IO
±25
IDD
ISS
Ptot
PO
Tstg
Tamb
±100
±100
400
supply current
total power dissipation
power dissipation per output
storage temperature
100
−65
−40
+150
+85
ambient temperature
°C
9
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
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
VDD
IDD
supply voltage
2.5
−
6.0
V
supply current
operating mode; VDD = 6 V;
−
40
100
µA
no load; VI = VDD or VSS
;
fSCL = 100 kHz
Istb
standby current
standby mode; VDD = 6 V;
no load; VI = VDD or VSS
−
−
2.5
1.3
10
µA
VPOR
Power-on reset voltage
VDD = 6 V; no load;
2.4
V
VI = VDD or VSS; note 1
Input SCL; input/output SDA
VIL
VIH
IOL
IL
LOW level input voltage
−0.5
−
−
−
−
−
+0.3VDD
V
HIGH level input voltage
LOW level output current
leakage current
0.7VDD
VDD + 0.5
V
VOL = 0.4 V
VI = VDD or VSS
VI = VSS
3
−
mA
µA
pF
−1
−
+1
7
Ci
input capacitance
2002 Nov 22
14
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
SYMBOL
I/Os
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
VIL
LOW level input voltage
HIGH level input voltage
−0.5
−
−
−
+0.3VDD
VDD + 0.5
±400
V
V
VIH
0.7VDD
IIHL(max)
maximum allowed input
current through protection
diode
VI ≥ VDD or VI ≤ VSS
−
µA
IOL
LOW level output current
HIGH level output current
transient pull-up current
VOL = 1 V; VDD = 5 V
VOH = VSS
10
30
−
25
−
−
mA
µA
IOH
IOHt
300
−
HIGH during acknowledge
−1
mA
(see Fig.15); VOH = VSS
VDD = 2.5 V
;
Ci
input capacitance
output capacitance
−
−
−
−
10
10
pF
pF
Co
Port timing; CL ≤ 100 pF (see Figs 11 and 12)
tpv
tsu
th
output data valid
−
0
4
−
−
−
4
−
−
µs
µs
µs
input data set-up time
input data hold time
Interrupt INT (see Fig.14)
IOL LOW level output current
IL leakage current
TIMING; CL ≤ 100 pF
VOL = 0.4 V
1.6
−
−
−
mA
VI = VDD or VSS
−1
+1
µA
tiv
tir
input data valid time
reset delay time
−
−
−
−
4
4
µs
µs
Select inputs A0 to A2
VIL
VIH
ILI
LOW level input voltage
−0.5
−
−
−
+0.3VDD
VDD + 0.5
+250
V
HIGH level input voltage
input leakage current
0.7VDD
−250
V
pin at VDD or VSS
nA
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).
2002 Nov 22
15
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.16; note 1)
fSCL
SCL clock frequency
tolerable spike width on bus
bus free time
−
−
−
−
−
−
−
−
−
−
−
−
−
−
100
kHz
tSW
−
100
−
ns
µs
µs
µs
µs
µs
µs
µs
ns
ns
µs
µs
tBUF
4.7
4.7
4.0
4.7
4.0
−
tSU;STA
tHD;STA
tLOW
tHIGH
tr
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
1.0
0.3
−
tf
−
tSU;DAT
tHD;DAT
tVD;DAT
tSU;STO
250
0
data hold time
−
SCL LOW to data out valid
STOP condition set-up time
−
3.4
−
4.0
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
.
START
CONDITION
(S)
BIT 7
MSB
(A7)
BIT 6
(A6)
BIT 0
LSB
(R/W)
ACKNOWLEDGE
(A)
STOP
CONDITION
(P)
PROTOCOL
t
t
t
HIGH
SU;STA
LOW
1 / f
SCL
SCL
SDA
t
t
t
f
BUF
r
t
t
t
t
t
HD;STA
SU;DAT
VD;DAT
SU;STO
HD;DAT
MBD820
Fig.16 I2C-bus timing diagram.
16
2002 Nov 22
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)
SOT38-4
D
M
E
A
2
A
A
1
L
c
e
w M
Z
b
1
(e )
1
b
b
2
16
9
M
H
pin 1 index
E
1
8
0
5
10 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
(1)
Z
A
A
A
2
(1)
(1)
1
w
UNIT
mm
b
b
b
c
D
E
e
e
L
M
M
H
1
2
1
E
max.
min.
max.
max.
1.73
1.30
0.53
0.38
1.25
0.85
0.36
0.23
19.50
18.55
6.48
6.20
3.60
3.05
8.25
7.80
10.0
8.3
4.2
0.51
3.2
2.54
0.10
7.62
0.30
0.254
0.01
0.76
0.068 0.021 0.049 0.014
0.051 0.015 0.033 0.009
0.77
0.73
0.26
0.24
0.14
0.12
0.32
0.31
0.39
0.33
inches
0.17
0.020
0.13
0.030
Note
1. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
REFERENCES
OUTLINE
EUROPEAN
PROJECTION
ISSUE DATE
VERSION
IEC
JEDEC
EIAJ
92-11-17
95-01-14
SOT38-4
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
H
v
M
A
E
y
Z
16
9
Q
A
2
A
(A )
3
A
1
pin 1 index
θ
L
p
L
1
8
detail X
e
w
M
b
p
0
5
10 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
A
max.
(1)
(1)
(1)
UNIT
A
A
A
b
c
D
E
e
H
L
L
Q
v
w
y
θ
1
2
3
p
E
p
Z
0.30
0.10
2.45
2.25
0.49
0.36
0.32
0.23
10.5
10.1
7.6
7.4
10.65
10.00
1.1
0.4
1.1
1.0
0.9
0.4
mm
2.65
1.27
0.050
1.4
0.25
0.01
0.25
0.1
0.25
0.01
8o
0o
0.012 0.096
0.004 0.089
0.019 0.013 0.41
0.014 0.009 0.40
0.30
0.29
0.419
0.394
0.043 0.043
0.016 0.039
0.035
0.016
inches 0.10
0.055
0.01 0.004
Note
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
REFERENCES
OUTLINE
EUROPEAN
PROJECTION
ISSUE DATE
VERSION
IEC
JEDEC
EIAJ
97-05-22
99-12-27
SOT162-1
075E03
MS-013
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
H
v
M
A
E
Z
11
20
Q
A
2
A
(A )
3
A
1
pin 1 index
θ
L
p
L
1
10
detail X
w
M
b
p
e
0
2.5
5 mm
scale
DIMENSIONS (mm are the original dimensions)
A
(1)
(1)
(1)
UNIT
A
A
A
b
c
D
E
e
H
L
L
p
Q
v
w
y
Z
θ
1
2
3
p
E
max.
10o
0o
0.15
0
1.4
1.2
0.32
0.20
0.20
0.13
6.6
6.4
4.5
4.3
6.6
6.2
0.75
0.45
0.65
0.45
0.48
0.18
mm
1.5
0.65
1.0
0.2
0.25
0.13
0.1
Note
1. Plastic or metal protrusions of 0.20 mm maximum per side are not included.
REFERENCES
OUTLINE
EUROPEAN
PROJECTION
ISSUE DATE
VERSION
IEC
JEDEC
EIAJ
95-02-22
99-12-27
SOT266-1
MO-152
2002 Nov 22
19
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
13 SOLDERING
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.
13.1 Introduction
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).
13.3.2 WAVE SOLDERING
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.
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:
13.2 Through-hole mount packages
• Use a double-wave soldering method comprising a
turbulent wave with high upward pressure followed by a
smooth laminar wave.
13.2.1 SOLDERING BY DIPPING OR BY SOLDER WAVE
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.
• 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;
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.
– 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.
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
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.
300 and 400 °C, contact may be up to 5 seconds.
13.3 Surface mount packages
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.
13.3.1 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.
13.3.3 MANUAL SOLDERING
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.
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.
2002 Nov 22
20
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
13.4 Suitability of IC packages for wave, reflow and dipping soldering methods
SOLDERING METHOD
WAVE
REFLOW(2) DIPPING
suitable(3)
BGA, LBGA, LFBGA, SQFP, TFBGA, VFBGA not suitable
MOUNTING
PACKAGE(1)
Through-hole mount DBS, DIP, HDIP, SDIP, SIL
−
suitable
Surface mount
suitable
suitable
−
−
HBCC, HBGA, HLQFP, HSQFP, HSOP,
HTQFP, HTSSOP, HVQFN, HVSON, SMS
not suitable(4)
PLCC(5), SO, SOJ
LQFP, QFP, TQFP
SSOP, TSSOP, VSO
suitable
suitable
−
−
−
not recommended(5)(6) suitable
not recommended(7)
suitable
Notes
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
PCF8574
14 DATA SHEET STATUS
DATA SHEET
STATUS(1)
PRODUCT
STATUS(2)(3)
LEVEL
DEFINITION
I
Objective data
Development 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.
II
Preliminary data Qualification
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.
III
Product data
Production
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).
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
16 DISCLAIMERS
Short-form specification
The data in a short-form
Life support applications
These products are not
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.
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.
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.
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
Application information
Applications that are
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.
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.
2002 Nov 22
22
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I2C-bus
PCF8574
17 PURCHASE OF PHILIPS I2C COMPONENTS
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.
© 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
相关型号：
PCF8574ATS/3,118
PCF8574; PCF8574A - Remote 8-bit I/O expander for I²C‑bus with interrupt SSOP2 20-Pin
NXP
PCF8574ATS/F3
IC 8 I/O, PIA-GENERAL PURPOSE, PDSO20, 4.40 MM, PLASTIC, MO-152, SOT-266-1, SSOP-20, Parallel IO Port
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