10-Bit Digital Temperature Sensor and Four Channel ADC

The AD7417 and AD7418 are 10-bit, 4-channel and single-channel ADCs with an on-chip temperature sensor that can operate from a single 2.7 V to 5.5 V power supply. The devices contain a 15 μs successive approximation converter, a 5-channel multiplexer, a temperature sensor, a clock oscillator, a track-and-hold, and a reference (2.5 V). The AD7416 is a temperature-monitoring only device in an 8-lead package.

The temperature sensor on the parts can be accessed via multiplexer Channel 0. When Channel 0 is selected and a conversion is initiated, the resulting ADC code at the end of the conversion gives a measurement of the ambient temperature (±1°C @ 25°C). On-chip registers can be programmed with high and low temperature limits, and an open-drain overtemperature indicator (OTI) output is provided, which becomes active when a programmed limit is exceeded.

A configuration register allows programming of the sense of the OTI output (active high or active low) and its operating mode (comparator or interrupt). A programmable fault queue counter allows the number of out-of-limit measurements that must occur before triggering the OTI output to be set to prevent spurious triggering of the OTI output in noisy environments.

An I2C® compatible serial interface allows the AD7416/AD7417/ AD7418 registers to be written to and read back. The three LSBs of the AD7416/AD7417 serial bus address can be selected, which allows up to eight AD7416/AD7417 devices to be connected to a single bus.

The AD7417 is available in a narrow body, 0.15 inch, 16-lead, small outline package (SOIC) and in a 16-lead, thin shrink, small outline package (TSSOP). The AD7416 and AD7418 are available in 8-lead SOIC and MSOP packages.

Product Highlights

* The AD7416/AD7417/AD7418 have an on-chip temperature

sensor that allows an accurate measurement of the ambient

temperature (±1°C @ 25°C, ±2°C overtemperature) to be

made. The measurable temperature range is −40°C to

+125°C. An overtemperature indicator is implemented by

carrying out a digital comparison of the ADC code for

Channel 0 (temperature sensor) with the contents of the

on-chip TOTI setpoint register.

* The AD7417 offers a space-saving, 10-bit analog-to-digital

solution with four external voltage input channels, an onchip

temperature sensor, an on-chip reference, and a clock

oscillator.

* The automatic power-down feature enables the AD7416/

AD7417/AD7418 to achieve superior power performance.

At slower throughput rates, the part can be programmed to

operate in a low power shutdown mode, allowing further

savings in power consumption.

Applications

* Data acquisition with ambient temperature monitoring

* Industrial process control

* Automotive

* Battery-charging applications

* Personal computers

* 10-bit ADC with 15 μs and 30 μs conversion times

* 4 single-ended analog input channels

* On-chip temperature sensor: −40°C to +125°C

* On-chip track-and-hold

* Overtemperature indicator

* Automatic power-down at the end of a conversion

* Wide operating supply range: 2.7 V to 5.5 V

* I2C-compatible serial interface

* Selectable serial bus address allows connection of up to 8 AD7416/AD7417 devices to a single bus