ISL12008 Datasheet, PDF (2/19 Pages) Intersil Corporation – I2C Real Time Clock with Battery Backup

Block Diagram
SDA
SCL
SDA
BUFFER
SCL
BUFFER
ISL12008
I²C
INTERFACE
RTC
CONTROL
LOGIC
X1
X2
V_DD
V_TRIP
V_BAT
CRYSTAL
OSCILLATOR
RTC
DIVIDER
POR
FREQUENCY
OUT
SWITCH
INTERNAL
SUPPLY
SECONDS
MINUTES
HOURS
DAY OF WEEK
DATE
MONTH
YEAR
CONTROL
REGISTERS
FT/OUT
Pin Descriptions
PIN
NUMBER SYMBOL
DESCRIPTION
1
X1 The X1 pin is the input of an inverting amplifier and is intended to be connected to one pin of an external 32.768kHz quartz
crystal. X1 can also be driven directly from a 32.768kHz source.
2
X2 The X2 pin is the output of an inverting amplifier and is intended to be connected to one pin of an external 32.768kHz quartz
crystal.
3
V_BAT This input provides a backup supply voltage to the device. V_BAT supplies power to the device in the event that the V_DD supply
fails. This pin should be tied to ground if not used.
4
GND Ground
5
SDA Serial Data (SDA) is a bidirectional pin used to transfer serial data into and out of the device. It has an open drain output and
may be wire OR’ed with other open drain or open collector outputs.
6
SCL The Serial Clock (SCL) input is used to clock all serial data into and out of the device.
7
FT/OUT 512Hz Frequency Output or digital output pin. The function is set via the configuration register. This pin is open drain and
requires an external pull-up resistor.
8
V_DD Power supply
2
FN6690.1
September 26, 2008