Isolated Sigma-Delta Modulator
Preliminary Technical Data
AD7400/AD7401
FEATURES
Up to 20 MHz Data Rate (AD7401)
10 MHz Data Rate (AD7400)
2
nd
Order Modulator
±4 LSB INL @16 Bits
Onboard Digital Isolator
Onboard Reference
Low Power Operation:
15 mA @ 5 V
-40H11034C to +105H11034C Operating Range
16-ld SOIC Package
Safety and Regulatory Approvals
UL Recognition
3750 VRMS for 1 minute per UL 1577
CSA Component Acceptance Notice ~5A
VDE Certificate of Conformity
DIN EN 60747-5-2 (VDE 0884 Part 2):2003-01
DIN EN 60950 (VDE 0805): 2001-12; EN 60950:2000
VIORM = 840VPEAK



APPLICATIONS
AC Motor Control
Data Acquisition Systems
A/D + Opto-Isolator Replacement
GENERAL DESCRIPTION
The AD7400/AD7401 are 2nd order sigma-delta modulators
that convert an analog input signal into a high speed 1-bit data
stream with onboard digital isolation based on Analog Devices’
iCoupler® technology. The AD7400/AD7401 operate from a 5 V
power supply and accept a differential input signal of ±200 mV.
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 data rates up to 20MHz. The
original information can be reconstructed with an appropriate
digital filter. The serial I/O may use a 5V or 3V supply (VDD2).
The serial interface is digitally isolated. High-speed CMOS,

FUNCTIONAL BLOCK DIAGRAM
UPDATE
ENCODE DECODE
WATCHDOG
T/H
V
DD1
Σ-∆ ADC
MCLKOUT*
CONTROL LOGIC
MDAT
GND
1

V
DD2
GND
2

V
IN
+
V
IN
-
REF
BUF
UPDATE
ENCODE DECODE
WATCHDOG
*MCLKIN pin on AD7401






Rev. PrH
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