DS1621 digital thermometer pinout

The DS1621 measures temperature over a two-wire bus and provides an independent thermostat output with programmable hysteresis.

SO-8 · 208 mil

8 contacts Current package

Analog Devices / Maxim Integrated ·

Top view. Start at the package pin-1 index and follow the numbered leads.

Input · Address

Hardware address bit 0. Tie to VDD or ground.

Analog Devices / Maxim DS1621 Rev. 4, pp. 1–5 and 8–12.

Pin	Signal	Direction	Function
1	SDA Bidirectional	Bidirectional	Open-drain I²C data. The bus needs a pull-up to its logic rail.
2	SCL Input	Input	I²C clock. Connect to the host clock line with its bus pull-up.
3	TOUT Output	Output	Thermostat signal controlled by TH, TL and the output polarity bit.
4	GND Supply return	Supply return	Connect to the common ground plane or bench return.
5	A2 Input	Input	Hardware address bit 2. Tie to VDD or ground.
6	A1 Input	Input	Hardware address bit 1. Tie to VDD or ground.
7	A0 Input	Input	Hardware address bit 0. Tie to VDD or ground.
8	VDD Supply input	Supply input	Device supply. Place the bypass capacitor close to this pin.

Address range 0x48–0x4F from A2:A0. The sensor starts idle. Send Start Convert T (0xEE) before reading temperature.

Parameter	Limit	Conditions and source
Supply2.7–5.5 V	2.7–5.5 V	Power the host and DS1621 from a compatible logic rail. Analog Devices / Maxim DS1621 Rev. 4, pp. 1–5 and 8–12.
Temperature range−55 to +125 °C	−55 to +125 °C	9-bit result with a 0.5 °C step. Analog Devices / Maxim DS1621 Rev. 4, pp. 1–5 and 8–12.
Conversion time1 s maximum	1 s maximum	A command starts conversion. Read the DONE bit to detect completion. Analog Devices / Maxim DS1621 Rev. 4, pp. 1–5 and 8–12.

Package maps follow the manufacturer’s package drawings. Use the package code on the actual part to distinguish narrow and wide SO bodies.

DS1621 manufacturer documentation· Analog Devices / Maxim DS1621 Rev. 4, pp. 1–5 and 8–12.