General Description
The DS1859 dual, temperature-controlled, nonvolatile (NV) variable resistors with three monitors consists of two 50kΩ 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 temperature-compensating bias voltages and currents in control applications using minimal circuitry. The variable resistor settings are stored in EEPROM memory and can be accessed over the 2-wire serial bus.

Features
♦ SFF-8472 Compatible
♦ Five Monitored Channels (Temperature, VCC, 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

Applications
Optical Transceivers
Optical Transponders
Instrumentation and Industrial Controls
RF Power Amps
Diagnostic Monitoring