1 Features

• Programmable FIR filter

• Programmable IIR filter

• Wideband or low-latency filter modes

• Programmable data rates:

– Wideband filter: 512 kSPS

– Low-latency filter: 1.365 MSPS

• Conversion latency (low-latency filter): 3 μs

• AC accuracy with dc precision:

– Dynamic range (200 kSPS): 111.5 dB (typical)

– THD: –125 dB (typical)

– INL: 0.4 ppm of FS (typical)

– Offset drift: 50 nV/°C (typical)

– Gain drift: 0.5 ppm/°C (typical)

• Power-scalable speed ranges:

– Max speed: 512 kSPS, 33 mW (typical)

– High speed: 400 kSPS, 26 mW (typical)

– Mid speed: 200 kSPS, 14 mW (typical)

– Low speed: 50 kSPS, 4.3 mW (typical)

• Input range: ±VREF or ±2 VREF

• Buffered inputs

• Internal or external clock operation

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

2 Applications

• Test and measurement:

– Data acquisition (DAQ)

– Acoustics and dynamic strain gauges

• Factory automation and control:

– Vibration, condition monitoring

• Medical:

– Doppler ultrasound

• Grid infrastructure:

– Power quality analyzers

3 Description

The ADS127L21 is a 24-bit, delta-sigma (ΔΣ), analogto-

digital converter (ADC) featuring a programmable

digital filter with data rates up to 512 kSPS using

the wideband filter and up to 1365 kSPS using

the low-latency filter. The device offers an excellent

combination of ac performance and dc precision with

low power consumption.

Programmable infinite and finite impulse response

(IIR and FIR) digital filters allow custom filter profiles,

such as A-weighting compensation and frequency

notch filters. The wideband or low-latency filter option

optimize ac-signal performance or data throughput of

dc signals, all in one device.

The low-drift modulator achieves excellent dc

precision with low wideband noise for outstanding

ac performance. The power-scalable architecture

features four speed modes to optimize data rate,

resolution, and power consumption. Signal and

reference input buffers reduce driver loading for

increased accuracy.

The serial interface features daisy-chain capability to

reduce the number of signal lines over an isolation

barrier. SPI input data and register memory contents

are validated by cyclic-redundancy check (CRC) to

enhance operational reliability.

The small 3-mm × 3-mm WQFN package is designed

for space-limited applications. The device is fully

specified for operation over the –40°C to +125°C

temperature range.