Dual, Temperature-Controlled Resistors with

Internally Calibrated Monitors

______________________________________________ Maxim Integrated Products

1

For pricing delivery, and ordering information please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

General Description

The DS1859 dual, temperature-controlled, nonvolatile

(NV) variable resistors with three monitors consists of

two 50k

Ω or two 20kΩ, 256-position, linear, variable

resistors; three analog monitor inputs (MON1, MON2,

MON3); and a direct-to-digital temperature sensor. The

device provides an ideal method for setting and tem-

perature-compensating bias voltages and currents in

control applications using minimal circuitry. The vari-

able resistor settings are stored in EEPROM memory

and can be accessed over the 2-wire serial bus.

Applications

Optical Transceivers

Optical Transponders

Instrumentation and Industrial Controls

RF Power Amps

Diagnostic Monitoring

Features

♦ SFF-8472 Compatible

MON1, MON2, MON3)

♦ Three External Analog Inputs (MON1, MON2, MON3)

That Support Internal and External Calibration

♦ Scalable Dynamic Range for External Analog Inputs

♦ Internal Direct-to-Digital Temperature Sensor

♦ Alarm and Warning Flags for All Monitored

Channels

♦ Two 50kΩ or Two 20kΩ, Linear, 256-Position,

Nonvolatile Temperature-Controlled Variable

Resistors

♦ Resistor Settings Changeable Every 2°C

♦ Access to Monitoring and ID Information

Configurable with Separate Device Addresses

♦ 2-Wire Serial Interface

♦ Two Buffers with TTL/CMOS-Compatible Inputs and

Open-Drain Outputs

♦ Operates from a 3.3V or 5V Supply

♦ Operating Temperature Range of -40°C to +95°C

Ordering Information

Rev 1; 11/03

PART

RESISTANCE

PIN-PACKAGE

DS1859E-050

50k

Ω

16 TSSOP

DS1859E-020

20k

Ω

16 TSSOP

DS1859E-050/T&R

50k

Ω

16 TSSOP

(Tape-and-Reel)

DS1859E-020/T&R

20k

Ω

16 TSSOP

(Tape-and-Reel)

DS1859B-050

50k

Ω

16-Ball CSBGA

DS1859B-020

20k

Ω

16-Ball CSBGA

A

TOP VIEW

B

C

D

1

CSBGA (4mm x 4mm)

1.0mm PITCH

TSSOP

3

24

MON3

OUT1

IN2

MON1

L0

GND

WPEN

L1

H0

SDA

OUT2

H1

SCL

IN1

MON2

DS1859

SDA

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

SCL

OUT1

IN1

OUT2

IN2

WPEN

GND

H1

L1

H0

L0

MON3

MON2

MON1

Pin Configurations

DS1859

SDA

1

2

3

4

5

6

7

8

16

0.1

µF

15

14

13

12

11

10

9

SCL

OUT1

IN1

OUT2

IN2

WPEN

GND

H1

L1

H0

L0

MON3

MON2

MON1

GROUND TO

DISABLE WRITE

PROTECT

Rx POWER*

DIAGNOSTIC

INPUTS

TO LASER

MODULATION

CONTROL

TO LASER BIAS

CONTROL

DECOUPLING

CAP

Tx POWER*

Tx BIAS*

*SATISFIES SFF-8472 COMPATIBILITY

4.7k

Ω

4.7k

Ω

Tx-FAULT

LOS

2-WIRE

INTERFACE

Typical Operating Circuit