FOR AUTOMOTIVE 105

°C OPERATION 2-WIRE SERIAL E

S-24CS01A/02A/04A H Series

19



Using S-24CS01A/02A/04A

1. Adding a pull-up resistor to SDA I/O pin and SCL input pin

Add a 1 k

Ω to 5 kΩ pull-up resistor to the SCL input pin

I

*1.

When the SCL input pin of the S-24CS01A/02A/04A is connected to a tri-state output pin of the microprocessor,

connect the same pull-up resistor to prevent a high impedance status from being input to the SCL input pin.

This protects the S-24CS01A/02A/04A from malfunction due to an undefined output (high impedance) from the tri-

state pin when the microprocessor is reset when the voltage drops.

2. Equivalent circuit of input and I/O pin

The I/O pins of this IC do not include pull-up and pull-down resistors. The SDA pin is an open-drain output. The following

shows the equivalent circuits.

SCL

Figure 21 SCL Pin

SDA

Figure 22 SDA Pin