GENERAL DESCRIPTION

The AD7401A1 is a second-order, sigma-delta (Σ-Δ) modulator

that converts an analog input signal into a high speed, 1-bit data

stream with on-chip digital isolation based on the Analog

Devices, Inc., iCoupler® technology. The AD7401A operates

from a 5 V power supply and accepts a pseudo-differential input

signal of ±250 mV (±320 mV full scale). The analog input is

continuously sampled by the analog modulator, eliminating the

need for external sample-and-hold circuitry. The input

information is contained in the output stream as a density of

ones with a data rate of up to 20 MHz. The original information

can be reconstructed with an appropriate digital filter. The

serial I/O can use a 5 V or a 3.3 V supply (VDD2).

The serial interface is digitally isolated. High speed CMOS,

combined with Analog Devices, Inc., iCoupler® technology ,

means the on-chip isolation provides outstanding performance

characteristics, superior to alternatives such as optocoupler

devices. The device contains an on-chip reference. The

AD7401A is offered in a 16-lead SOIC and has an operating

temperature range of −40°C to +125°C.

FEATURES

20 MHz maximum external clock rate

Second-order modulator

16 bits, no missing codes

±2 LSB INL typical at 16 bits

1 µV/°C typical offset drift

On-board digital isolator

On-board reference

±250 mV analog input range

Low power operation: 17 mA typical at 5.5 V

−40°C to +125°C operating range

16-lead SOIC package

Internal clock version: AD7400A

Safety and regulatory approvals

UL recognition

5000 V rms for 1 minute per UL 1577

CSA Component Acceptance Notice #5A

VDE Certificate of Conformity

DIN V VDE V 0884-10 (VDE V 0884-10):2006-12

VIORM = 891 V peak

Qualified for Automotive Applications

APPLICATIONS

AC motor controls

Shunt current monitoring

Data acquisition systems

Analog-to-digital and opto-isolator replacements