Philips Semiconductors
Product specification
256
×
8-bit static low-voltage RAM with
I
2
C-bus interface
CONTENTS
1
2
3
4
5
6
7
8
8.1
8.2
8.3
8.4
8.5
9
10
11
12
13
13.1
13.2
13.3
14
15
15.1
15.2
15.2.1
15.2.2
15.3
15.3.1
15.3.2
15.3.3
15.4
16
17
18
FEATURES
APPLICATIONS
GENERAL DESCRIPTION
QUICK REFERENCE DATA
ORDERING INFORMATION
BLOCK DIAGRAM
PINNING
CHARACTERISTICS OF THE I
2
C-BUS
Bit transfer
Start and stop conditions
System configuration
Acknowledge
I
2
C-bus protocol
LIMITING VALUES
HANDLING
DC CHARACTERISTICS
AC CHARACTERISTICS
APPLICATION INFORMATION
Application example
Slave address
Power-saving mode
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
DEFINITIONS
LIFE SUPPORT APPLICATIONS
PURCHASE OF PHILIPS I
2
C COMPONENTS
PCF8570
1999 Jan 06
2
Philips Semiconductors
Product specification
256
×
8-bit static low-voltage RAM with
I
2
C-bus interface
1
FEATURES
PCF8570
•
Operating supply voltage 2.5 to 6.0 V
•
Low data retention voltage; minimum 1.0 V
•
Low standby current; maximum 15
µA
•
Power-saving mode; typical 50 nA
•
Serial input/output bus (I
2
C-bus)
•
Address by 3 hardware address pins
•
Automatic word address incrementing
•
Available in DIP8 and SO8 packages.
2
APPLICATIONS
3
GENERAL DESCRIPTION
The PCF8570 is a low power static CMOS RAM,
organized as 256 words by 8-bits.
Addresses and data are transferred serially via a two-line
bidirectional bus (I
2
C-bus). The built-in word address
register is incremented automatically after each written or
read data byte. Three address pins, A0, A1 and A2 are
used to define the hardware address, allowing the use of
up to 8 devices connected to the bus without additional
hardware.
•
Telephony:
– RAM expansion for stored numbers in repertory
dialling (e.g. PCD33xxA applications)
•
General purpose RAM for applications requiring
extremely low current and low-voltage RAM retention,
such as battery or capacitor-backed.
•
Radio, television and video cassette recorder:
– channel presets
•
General purpose:
– RAM expansion for the microcontroller families
PCD33xxA, PCF84CxxxA, P80CLxxx and most other
microcontrollers.
4
QUICK REFERENCE DATA
SYMBOL
V
DD
I
DD
I
DDR
T
amb
T
stg
5
supply voltage
supply current (standby)
supply current (power-saving mode)
operating ambient temperature
storage temperature
PARAMETER
CONDITIONS
f
SCL
= 0 Hz
T
amb
= 25
°C
MIN.
2.5
−
−
−40
−65
MAX.
6.0
15
400
+85
+150
UNIT
µA
nA
°C
°C
ORDERING INFORMATION
TYPE
NUMBER
PACKAGE
NAME
DIP8
SO8
DESCRIPTION
plastic dual in-line package; 8 leads (300 mil)
plastic small outline package; 8 leads; body width 7.5 mm
VERSION
SOT97-1
SOT176-1
PCF8570P
PCF8570T
1999 Jan 06
3
Philips Semiconductors
Product specification
256
×
8-bit static low-voltage RAM with
I
2
C-bus interface
8
CHARACTERISTICS OF THE I
2
C-BUS
8.1
Bit transfer
PCF8570
The I
2
C-bus is for bidirectional, two-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. Data transfer may be initiated only when the bus
is not busy.
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 a control signal.
SDA
SCL
data line
stable;
data valid
change
of data
allowed
MBA607
Fig.3 Bit transfer.
8.2
Start and stop conditions
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).
SDA
SDA
SCL
S
START condition
P
STOP condition
SCL
MBA608
Fig.4 Definition of start and stop conditions.
1999 Jan 06
5
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