Datasheet LTC4302-1, LTC4302-2 (Analog Devices) - 5

LTC4302-1/LTC4302-2
U U U PI FU CTIO S SDAIN (Pin 1):
Serial Data Input. Connect this pin to the
GPIO1 (Pin 6):
General Purpose Input/Output (GPIO1). SDA bus on the backplane. Do not float. GPIO1 can be used as an input, an open-drain output or a push-pull output. The N-Channel MOSFET pulldown de-
SCLIN (Pin 2):
Serial Clock Input. Connect this pin to the vice is capable of driving LEDs. When used in input or SCL bus on the backplane. Do not float. open-drain output mode, the I/O pin can be pulled up to a
CONN (Pin 3):
Register Reset and Connection Sense supply voltage ranging from 2.2V to 5.5V independent of Input. Driving this pin low resets the registers to their the VCC voltage. default state: GPIOs in output open-drain high impedance
GPIO2 (Pin 7, LTC4302-1):
General Purpose Input/Out- mode, rise time accelerators disabled and the input-to- put. GPIO2 can be used as an input, an open-drain output, output connection disabled. Communication with the or a push-pull output. The N-Channel MOSFET pulldown LTC4302-1/LTC4302-2 is disabled when CONN is low. device is capable of driving LED’s. When used in input or When CONN is brought back high, the registers remain in open-drain output mode, the I/O pin can be pulled up to a the default state and communication is enabled. supply voltage ranging from 2.2V to 5.5V independent of
ADDRESS (Pin 4):
2-Wire Address Programming Input. the VCC voltage. The 2-wire address is programmed by connecting
V
ADDRESS to a resistive divider between V
CC2 (Pin 7, LTC4302-2):
Card Side Supply Voltage. This CC and ground. pin is a power supply pin for the card side busses. Connect The voltage on ADDRESS is converted by an internal V analog-to-digital (A/D) converter into a 5-bit digital word. CC2 to the card’s VCC and connect a bypass capacitor of at least 0.01µF directly between V This resulting digital code represents the least significant CC2 and GND for best results. five bits of the 2-wire address. 1% resistors must be used to ensure accurate address programming. 32 unique
VCC (Pin 8):
Main Input Power Supply from Backplane. addresses are possible. See Table 1 for 1% resistor values Connect a bypass capacitor of at least 0.01µF directly and corresponding addresses. Care must also be taken to between VCC and GND for best results. minimize capacitance on ADDRESS. Resistors must be
SCLOUT (Pin 9):
Serial Clock Output. Connect this pin to placed close to the LTC4302-1/LTC4302-2’s VCC, GND the SCL bus on the I/O card. Do not float. and ADDRESS pins.
SDAOUT (Pin 10):
Serial Data Output. Connect this pin to
GND (Pin 5):
Ground. Connect this pin to a ground plane the SDA bus on the I/O card. Do not float. for best results.
W U W TI I G DIAGRA
SDA t tSP SU, DAT t t SU, STA t HD, DATO, BUF t t HD, STA t HD, DATI SU, STO tSP 4302 TD01 SCL tHD, STA tf START REPEATED START STOP START CONDITION CONDITION CONDITION CONDITION sn430212 430212fs 5