1 Features

1• ±20-V input, 24-bit delta-sigma ADC

• Programmable data rate: 2.5 SPS to 40 kSPS

• High-voltage, high-impedance PGA:

– Differential input range: up to ±20 V

– Programmable gain: 0.125 to 128

– Common-mode input voltage: up to ±15.5 V

– Input impedance: 1 GΩ (minimum)

• High-performance ADC:

– Input noise: 45 nVRMS (20 SPS)

– CMRR: 105 dB

– Normal-mode rejection at 50 Hz, 60 Hz: 95 dB

– Offset drift: 5 nV/°C

– Gain drift: 1 ppm/°C

– INL: 2 ppm

• Integrated features and diagnostics:

– 2.5-V reference: 3 ppm/°C drift

– Clock oscillator: 2.5% error (maximum)

– Excitation current sources

– GPIO to drive external mux

– Signal and reference voltage monitors

– Cyclic redundancy check (CRC)

• Power supplies:

– AVDD: 4.75 V to 5.25 V

– DVDD: 2.7 V to 5.25 V

– HVDD: ±5 V to ±18 V

• Operating temperature: –40°C to +125°C

• 5-mm × 5-mm VQFN package

2 Applications

• PLC analog input modules:

– Voltage (such as ±10 V or 0 V to 5 V)

– Current (such as 4 mA to 20 mA with shunt)

– Temperature (such as RTDs, thermocouples)

• Test and measurement:

– High common-mode voltage inputs

– Battery testing

– High-side current measurement

3 Description

The ADS125H02 is a ±20-V input, 24-bit, delta-sigma

(ΔΣ) analog-to-digital converter (ADC). The ADC

features a low-noise programmable gain amplifier

(PGA), an internal reference, clock oscillator, and

signal or reference out-of-range monitors.

The integration of a wide input range, ±18-V PGA and

an ADC into a single package reduces board area up

to 50% compared to discrete solutions.

Programmable gain of 0.125 to 128 (corresponding to

an equivalent input range from ±20 V to ±20 mV)

eliminates the need for an external attenuator or

external gain stages. 1-GΩ minimum input impedance

reduces error caused by sensor loading. Additionally,

the low noise and low drift performance allow direct

connections to bridge, resistance temperature

detector (RTD), and thermocouple sensors.

The digital filter attenuates 50-Hz and 60-Hz line

cycle noise for data rates ≤ 50 SPS or 60 SPS to

reduce measurement error. The filter also provides

no-latency conversion data for high data throughput

during channel sequencing.

The ADS125H02 is housed in a 5-mm × 5-mm VQFN

package and is fully specified over the –40°C to

+125°C temperature range.