DIO1408

Version 1.0, Jul 2025

www.dioo.com

© 2025 Dioo Microcircuits Co., Ltd. Jiangsu

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8. Function Description

8.1. Overview

The DIO1408 is a digital temperature sensor for applications involving thermal management and protection. The

DIO1408 is specified over a temperature range of -40°C to 125°C and is compatible with SMBus and I2C

interface.

8.2. Serial bus

The DIO1408 is compatible with SMBus and I2C interface and operates as a slave device. Both SDA and SCL

are bidirectional lines, connected to positive supply voltage via a pull-up resistor. On-chip spike-suppression

filters reject spikes on the bus line to preserve data integrity. Data transfers of the DIO1408 can be made up to

400 kHz in the Fast-mode. Data is transferred with the Most Significant Bit(MSB) first.

8.2.1. Serial bus overview

The device which initiates a transfer, generates clock signals and terminates a transfer is called a master, and

the device addressed by a master is called a slave.

When bus is free, both lines are HIGH. All transactions begin with a START condition and are terminated by a

STOP condition. A START condition is defined as a HIGH to LOW transition on the SDA while SCL is HIGH. A

STOP condition is defined as a LOW to HIGH transition on the SDA while SCL is HIGH. After the START

condition, a slave address is sent to address a specific device. This address is seven bits long followed by an

eighth bit which is a data direction bit indicating whether a reading or writing operation is intended. The

addressed slave pulls the SDA line LOW during the ninth clock pulse to indicate that the address was

successfully received.

The data byte is then sent and the acknowledgement takes place after every byte. When all data are transferred,

a STOP condition terminates the transaction and the bus returns free.

8.2.2. Serial bus address

The DIO1408 can support up to four configurable slave addresses. The master can communicate with the

DIO1408 by sending the corresponding slave address byte. The first seven bits of this byte are slave address

bits, and the eighth bit is a data direction bit indicating whether a read or writing operation is intended. The

DIO1408 can decode the address based on the status of the address pin when transactions begin. Table 1

shows the pin status and the corresponding address values.

Table 1. Address pin and slave addresses

Device Two-wire Address

A0 Pin(1) Connection

1001000

Ground

1001001

V+

1001010

SDA

1001011

SCL

Note

(1) The value of resistance connected between A0 pin and V+/GND/SDA/ SCL is recommended less than 6.8 kΩ.