MAXIM DS620 Technical data

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www.maxim-ic.com

GENERAL DESCRIPTION

The DS620 digital thermometer and thermostat
provides low-voltage (1.7V ≤ V
measurements with ±0.5°C accuracy from 0°C to
+70°C and an operating temperature range of -55°C
to +125°C. The DS620 communicates over a 2-wire
digital interface. For distributed-sensing applications,
it is multidroppable with three address pins that allow
up to eight DS620s to operate on a single bus.

The DS620 has thermostat functionality with user­defined thresholds stored in EEPROM registers, and
it can be configured for standalone thermostat
operation. The programmable output (PO) pin serves
as the thermostat output, and this pin can also be
configured to function as an active-low control for
peripheral devices.

≤ 3.5V) temperature

DD

APPLICATIONS

Portable Applications
Low-Voltage Temperature-Sensitive Applications
Computers/Servers
Test Equipment
Medical Instruments
Industrial Applications

TYPICAL OPERATING CIRCUIT

DS620

0
1
2

1.7V to 3.5V

PO

Thermostat

1.7V to 3.5V

.

HOST

SDA
SCL

VDD
SDA
SCL

GND
PAD

DS620

Low-Voltage, ±0.5°C Accuracy

Digital Thermometer and Thermostat

FEATURES

 Low-Voltage Operation: 1.7V to 3.5V
 ±0.5°C Accuracy from 0°C to +70°C
 Operating Temperature Range: -55°C to +125°C

(-67°F to +257°F)

 Temperature Measurements Require No

External Components

 Resolution is User-Selectable to 10-, 11-, 12-, or

13-Bits (0.5°C, 0.25°C, 0.125°C, and 0.0625°C
LSb Weight, Respectively)

 Multidroppable
 Fast (200ms max) Temperature-to-Digital

Conversion Time

 Thermostatic Settings are User-Definable and

Nonvolatile

 Standalone Thermostat Capability
 Data is Read/Written Through a 2-Wire Serial

Interface

 Package: 8-Pin μSOP

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE

DS620U -55°C to +125°C

DS620U/T&R -55°C to +125°C

PIN CONFIGURATION

SD

SCL

PO

GND

8-Pin

μSOP Package

Exposed Pad

PAD

8 µSOP,
Exposed Pad
8 µSOP
Exposed Pad
Tape-and-Reel

VDD

0

1

2

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041607

DS620 Digital Thermometer and Thermostat

PIN DESCRIPTION

PIN NAME FUNCTION

1 SDA
2 SCL
3 PO

4 GND
5 A2
6 A1
7 A0
8 VDD

PAD

Figure 1. Block Diagram

DS620

SCL
SDA

Data Input/Output Pin for serial communication. Open drain. (No diode connection to VDD).
Clock Input Pin for 2-wire serial communication.
Programmable Output Pin. Open drain. (No diode connection to VDD).

Ground Pin.
Address Input Pin.
Address Input Pin. Also serves as an input to trigger one-shot conversions during standalone use.
Address Input Pin.
Supply Voltage Pin. +1.7V to +3.5V power supply pin.
PAD. Connect to GND or float. DO NOT CONNECT TO SUPPLY. The exposed pad is the best way to conduct

temperature into the package. Connecting PAD to a ground plane can assist in properly measuring the
temperature of the circuit board.

Temp. Core

Digital Control

Conversion Control

Address/Command

Decode

Address Counter

Memory Array

Configuration Register

TH, TL Registers

Digital Comparator

Temperature Register

Temperature Counter

User EEPROM Registers

Bandgap

ADC POR

2-Wire Interface

A2

A0

Memory Interface Logic

PO Pin
Control

Charge Pump

PO

A1

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DS620 Digital Thermometer and Thermostat

ABSOLUTE MAXIMUM RATINGS

Voltage Range on Any Pin, Relative to Ground -0.5V to +4.5V
Operating Temperature Range -55°C to +125°C
Storage Temperature Range
Soldering Temperature

-55°C to +125°C

See IPC/JEDEC J-STD-020A Specification

ESD rating on all pins 4KV HBM

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is
not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device.

RECOMMENDED DC OPERATING CONDITIONS

(3.5V ≥ VDD ≥ 1.7V, TA = -55°C to +125°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Voltage Range on Any Pin,
Relative to Ground
Supply Voltage for EEPROM
Writes

(Note 1) 1.7 3.5 V

V

DD

(Note 1) 2.0 3.5 V

V

DD

DC ELECTRICAL CHARACTERISTICS

(3.5V ≥ VDD ≥ 1.7V, TA = -55°C to +125°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

0°C to +70°C ±0.5

Thermometer Error T

Input Logic High VIH (Note 1)

Input Logic Low VIL (Note 1) - 0.5

SDA Output Logic Low Voltage

ERR

V

OL1

V

OL2

-55°C to +125°C ±2

0.7 x
V

DD

3mA sink current (Note 1) 0 0.4
6mA sink current (Note 1) 0 0.6

V

DD

0.5

0.3 x
V

DD

+

PO Saturation Voltage VOL 4mA sink current (Note 1) 0 0.4 V
Input Current for each I/O pin 0.4 < V

I/O Capacitance C
Standby Current I

10 pF

I/O

0°C to +70°C (Note 2) 2 µA

STBY

Temperature conversion, ­55°C to +85°C (Note 3)

Active Supply Current IDD

Temperature conversion,
+85°C to +125°C (Note 3)

2

write (Note 3) 500 µA

E

< 0.9 x VDD -10 +10 µA

I/O

800

900

10 bit 25

Temperature Conversion Time TTC

11 bit 50
12 bit 100
13 bit 200

Note 1: All voltages are referenced to GND.
Note 2: Specified with SDA = V
Note 3: Specified with A

, A1, A2 = 0V or VDD.

0

; A0, A1, A2 = 0V or VDD.

DD

°C

V

V

V

µA

ms

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DS620 Digital Thermometer and Thermostat

AC ELECTRICAL CHARACTERISTICS

EEPROM AC Electrical Characteristics

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

EEPROM Write Cycle Time TWR -40°C to +85°C 10 ms

-40°C ≤ TA ≤ +85°C

EEPROM Writes N

EEPROM Data Retention t

EEWR

EEDR

(Note 1)
T

= +25°C (Note 1) 40k 80k

A

-40°C to +125°C (Note 2) 10 years

2-Wire AC Electrical Characteristics

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SCL Frequency f
Bus Free Time Between a
STOP and START Condition
START and Repeat START
Hold Time from Falling SCL
Low Period of SCL t

High Period of SCL t
Repeated START Condition

Setup Time to Rising SCL
Data-Out Hold Time from
Falling SCL
Data-In Setup Time to Rising
SCL

0 400 KHz

SCL

t

1.3 µs

BUF

t

(Note 3, 4) 0.6 µs

HD:STA

(Note 3) 1.3 µs

LOW

(Note 3) 0.6 µs

HIGH

t

(Note 3) 0.6 µs

SU:STA

t

(Note 3) 0 0.9 µs

HD:DAT

(Note 3) 100 ns

t

SU:DAT

Rise Time of SDA and SCL tR (Note 3, 5)

Fall Time of SDA and SCL tF (Note 3, 5)

STOP Setup Time to Rising
SCL
Capacitive Load for Each BUS
Line

T

0.6 µs

SU:STO

C

400 pF

B

Input Capacitance CI 10 pF
Spike Pulse Width that can be

Suppressed by Input Filter

Note 1: V
Note 2: Write done at 25°C.
Note 3: All values referenced to 0.9 V
Note 4: After this period the first clock pulse is generated.
Note 5: For example, if C

must be 2.0V to 3.5V.

DD

= 300pF, then tR(MIN) = tF(MIN) = 50ns.

B

and 0.1 V

DD

0 50 ns

.

DD

10k 20k

20 +

0.1xC
20 +

0.1xC

B

B

1000 ns

300 ns

writes

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Figure 2. Timing Diagram

DS620 Digital Thermometer and Thermostat

Table 1. Register Summary

Parameter Information

TH and TL Registers
Size: 2-Bytes

Note that the 3 LSbs are always “don’t cares” for writes

(i.e., they are not saved) and always read out as 0s.

Configuration Register
Size: 2-Bytes
Temperature Register
Size: 2-Bytes

EEPROM
Factory State:
TH = 15ºC (0000 0111 1000 0000) [0780h]
TL = 10ºC (0000 0101 0000 0000) [0500h]

SRAM and EEPROM. See Figure 4 and Table 5 for
detailed information and power-up/factory state.
SRAM Power-Up State: -60ºC
(1110 0010 0000 0000) [E200h]

TEMPERATURE MEASUREMENT

The DS620 measures temperature using a bandgap-based temperature sensor. A delta-sigma, analog-to-digital
converter (ADC) converts measured temperature to a 10-, 11-, 12-, or 13-bit (user-selectable) digital value that is
calibrated in °C; for °F applications, a lookup table or conversion routine must be used. Throughout this data sheet,
the term “conversion” is used to refer to the entire temperature measurement and ADC sequence.

The DS620 can be configured to power up either automatically converting temperature or in a low-power standby
state. The preferred power-up mode can be set using the AUTOC bit in the configuration register as explained in

the Configuration Register section of this data sheet.

The DS620 can be programmed to perform continuous consecutive conversions (continuous conversion mode) or
to perform single conversions on command (one-shot mode). The conversion mode is programmed through the

1SHOT bit in the configuration register as explained in the Configuration Register section of this data sheet. In

continuous conversion mode, conversions are performed after a Start Convert command is issued (or upon power­up if the AUTOC bit in the configuration register is set to 1) until a Stop Convert command is issued, at which time
the device goes into a low-power standby state. Continuous conversions can be restarted at any time using the
Start Convert command. In one-shot mode, the DS620 performs a single temperature conversion either at power­up (if AUTOC = 1) or when a Start Convert command is issued (if AUTOC = 0). When the conversion is complete,

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