The ISL21400 features a precision voltage referencecombined with a temperature sensor whose output voltagevaries linearly with temperature. The precision 1.20Vreference has a very low temperature coefficient (tempco),and its output voltage is scaled by an internal DAC (VREF) toproduce a temperature stable output voltage that isprogrammable from 0V to 1.20V. The output voltage from thetemperature sensor (VTS) is summed with VREF to producea temperature dependent output voltage.The slope of the VTS portion of the output voltage can beprogrammed to be positive or negative in the range-2.1mV/°C to +2.1mV/°C. A programmable gain amplifier(PGA) sums the VTS and the VREF voltages and providesgains of 1x, 2x, and 4x to scale the output up to 4.8V and theslope to ±8.4mV/°C.The VREF and VTS terms are programmable with 8 bits ofresolution via an I2C bus and the values are stored innon-volatile registers. The PGA gain is also set via the I2Cbus and the value is stored in a non-volatile register.Non-volatile memory storage assures the programmedsettings are retained on power-down, eliminating the needfor software initialization at device power-up.