AD7401 Datasheet, PDF (1/20 Pages) Analog Devices – Isolated Sigma-Delta Modulator

Isolated Sigma-Delta Modulator
AD7401
FEATURES
16 MHz maximum external clock rate
Second-order modulator
16 bits no missing codes
±2 LSB INL typical at 16 bits
3.5 μV/°C maximum offset drift
On-board digital isolator
On-board reference
Low power operation: 18 mA maximum at 5.25 V
−40°C to +105°C operating range
16-lead SOIC_W package
AD7400, internal clock version
Safety and regulatory approvals
UL recognition
3750 Vrms for 1 min 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 = 891 V peak
GENERAL DESCRIPTION
The AD7401¹ is a second-order, Σ-Δ modulator that converts
an analog input signal into a high speed 1-bit data stream with
on-chip digital isolation based on Analog Devices’ iCoupler®
technology. The AD7401 operates from a 5 V power supply and
accepts a differential input signal of ±200 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 1s with a data rate up to 16 MHz. The
original information can be reconstructed with an appropriate
digital filter. The serial I/O can use a 5 V or 3 V supply (VDD2).
The serial interface is digitally isolated. High speed CMOS,
combined with monolithic air core transformer technology,
means the on-chip isolation provides outstanding performance
characteristics, superior to alternatives such as optocoupler
devices. The part contains an on-chip reference. The AD7401
is offered in a 16-lead SOIC_W and has an operating
temperature range of −40°C to +105°C.
APPLICATIONS
AC motor control
Data acquisition systems
A/D + opto-isolator replacements
1 _{Protected by U.S. Patents 5,952,849 and 6,291,907.}
FUNCTIONAL BLOCK DIAGRAM
V_DD1
V_DD2
V_IN+
T/H
V_IN–
Σ-Δ ADC
BUF
REF
CONTROL LOGIC
UPDATE
ENCODE
WATCHDOG
AD7401
WATCHDOG
DECODE
UPDATE
MDAT
DECODE
ENCODE
MCLKIN
GND₁
Figure 1.
GND₂
Rev. 0
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