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