Dallas Semiconductor DS56X, DS56U, DS56S Datasheet

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FEATURES

§ Factory calibrated for sensitivity of +6.20

mV/°C and thermometer accuracy of ±2.0°C
over the 0°C to 85°C range and ±3°C over the
40°C to 0°C and +85°C to +125°C range

§ Measurement range of -40°C to +125°C

§ Integrated temperature sensor and voltage

reference

§ Two independent temperature setpoints with

respective logic outputs with set hysteresis

§ Narrow-body SO8 (150-mil) package

§ Wide power supply range (2.7V ≤ VDD ≤

5.5V)

§ Functionally compatible with LM56xIM

§ Applications include monitoring disk drives,

printers, office equipment, HVAC,
appliances, or any power/cost/temperature­sensitive environments.

PIN ASSIGNMENT

PIN DESCRIPTION

V

REF

- Bandgap Voltage Reference
Output

V

T2

- Temperature Trip Point 2

V

T1

- Temperature Trip Point 1
GND - Ground
V

TEMP

- Temp Sensor Output Voltage
T

OUT2

- Thermostat output for Trip

Point 2

T

OUT1

- Thermostat output for Trip

Point 1

V

DD

- Power Supply Voltage (2.7V

to 5.5V)

DESCRIPTION

The DS56 Dual Temperature Comparator has two independent open-drain thermostat outputs and
respective trip point inputs. The trip points are set with external resistors that divide down the 1.25V
internal bandgap voltage reference. The voltage resulting from this resistive division is compared with the
voltage corresponding to the device’s junction temperature to define the thermostat output logic state. The
internal temperature sensor has a typical sensitivity of +6.2mV/°C and DC offset of +395 mV at 0°C.
Both thermostat outputs have 5°C of hysteresis.

For applications that require temperature measurement as well as control, the temperature sensor voltage
is brought out to a pin.

The DS56 is packaged in a compact 150-mil, 8-pin SOIC. Applications include disk drives, printers,
office equipment, HVAC, appliances, or any power/cost/temperature-sensitive environments.

DS56

Dual Temperature Comparator

PRELIMINARY

www.dalsemi.com

1
2
3
4

8
7
6
5

V

DD

T

OUT1

T

OUT2

V

TEMP

V

REF

V

T2

V

T1

GND

DS56S 8-Pin SOIC (150-mil)

DS56

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DETAILED PIN DESCRIPTION Table 1

PIN SYMBOL TYPE DESCRIPTION

1 V

REF

Analog output Bandgap output 1.25V (nom) voltage reference output.

2 V

T2

Analog input Trip point 2 input associated with thermostat output 2.

3 V

T1

Analog input Trip point 1 input associated with thermostat output 1.

4 GND GND

Ground pin.

5 V

TEMP

Analog output Temperature sensor output. (+6.2 T

DegC

+ 395) mV.

6 T

OUT2

Digital output

(open-drain)

Thermostat output 2. Active low output corresponding to trip
point 2. Typical hysteresis is 5.0°C.

7 T

OUT1

Digital output

(open-drain)

Thermostat output 1. Active low output corresponding to trip
point 1. Typical hysteresis is 5.0°C.

8 V

DD

V

DD

Supply Voltage 2.7V - 5.5V input power pin.

DS56 FUNCTIONAL BLOCK DIAGRAM Figure 1