DS1621

ORDERING INFORMATION

ORDERING

NUMBER

PACKAGE

MARKING

DESCRIPTION

DS1621

DS1621

DS1621 in 300 mil DIP

DS1621+

DS1621 (See Note)

DS1621 in Lead-Free 300 mil DIP

DS1621S

DS1621

DS1621 in 150 mil SOIC

DS1621S+

DS1621 (See Note)

DS1621 in Lead-Free 150 mil SOIC

DS1621S/T&R

DS1621

DS1621 in 150 mil SO, 2500 Piece Tape-and-Reel

DS1621S+T&R DS1621 (See Note)

DS1621 in Lead-Free 150 mil SO, 2500 Piece Tape-and-Reel

DS1621V

DS1621V

DS1621 in 208 mil SOIC

DS1621V+

DS1621V (See Note) DS1621 in Lead-Free 208 mil SOIC

DS1621V/T&R DS1621V

DS1621 in 208 mil SO, 2500 Piece Tape-and-Reel

DS1621V+T&R DS1621V (See Note) DS1621 in Lead-Free 208 mil SO, 2500 Piece Tape-and-Reel

Note: A “+” symbol will also be marked on the package near the Pin 1 indicator.

Table 1. DETAILED PIN DESCRIPTION

PIN

SYMBOL

DESCRIPTION

1

SDA

Data input/output pin for 2-wire serial communication port.

2

SCL

Clock input/output pin for 2-wire serial communication port.

3

Thermostat output. Active when temperature exceeds TH; will reset when

temperature falls below TL.

4

GND

Ground pin.

5

A2

Address input pin.

6

A1

Address input pin.

7

A0

Address input pin.

8

Supply voltage input power pin. (2.7V to 5.5V)

OPERATION

Measuring Temperature

A block diagram of the DS1621 is shown in Figure 1.

The DS1621 measures temperature using a bandgap-based temperature sensor. A delta-sigma analog-to-

digital converter (ADC) converts the measured temperature to a digital value that is calibrated in °C; for

°F applications, a lookup table or conversion routine must be used.

The temperature reading is provided in a 9-bit, two’s complement reading by issuing the READ

TEMPERATURE command. Table 2 describes the exact relationship of output data to measured

temperature. The data is transmitted through the 2-wire serial interface, MSB first. The DS1621 can

measure temperature over the range of -55°C to +125°C in 0.5°C increments.

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