ISL21400
Programmable Temperature Slope Voltage Reference

Key Features

• Programmable reference voltage
• Programmable temperature slope
• Programmable Gain Amplifier
• Non-volatile storage of programming registers
• I²C serial interface
• 2% total accuracy over temperature and V_CC range
• 200µA typical active supply current
• Operating temperature range = -40°C to +85°C
• 8 Ld MSOP package
• Pb-free (RoHS compliant)

Description

The ISL21400 features a precision voltage reference combined with a temperature sensor whose output voltage varies linearly with temperature. The precision 1.20V reference has a very low temperature coefficient (tempco), and its output voltage is scaled by an internal DAC (V_REF) to produce a temperature stable output voltage that is programmable from 0V to 1.20V. The output voltage from the temperature sensor (V_TS) is summed with V_REF to produce a temperature dependent output voltage.

The slope of the V_TS portion of the output voltage can be programmed to be positive or negative in the range -2.1mV/°C to +2.1mV/°C. A programmable gain amplifier (PGA) sums the V_TS and the V_REF voltages and provides gains of 1x, 2x, and 4x to scale the output up to 4.8V and the slope to ±8.4mV/°C.

The V_REF and V_TS terms are programmable with 8 bits of resolution via an I²C bus and the values are stored in non-volatile registers. The PGA gain is also set via the I²C bus and the value is stored in a non-volatile register. Non-volatile memory storage assures the programmed settings are retained on power-down, eliminating the need for software initialization at device power-up.

Applications

• RF power amplifier bias compensation
• LCD bias compensation
• Laser diode bias compensation
• Sensor bias and linearization
• Data acquisition systems
• Variable DAC reference
• Amplifier biasing