AD7400A Datasheet, PDF (1/19 Pages) Analog Devices – Isolated Sigma-Delta Modulator

Preliminary Technical Data
Isolated Sigma-Delta Modulator
AD7400A
FEATURES
10 MHz 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 +125°C operating range
16-lead SOIC, 8-lead gull-wing surface mount DIP packages
AD7401A, external clock version
Safety and regulatory approvals
UL recognition
3750 V rms 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 = 891 V peak
APPLICATIONS
GENERAL DESCRIPTION
The AD7400A¹ 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, Inc.
iCoupler® technology. The AD7400A 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 ones with a data rate of
10 MHz. The original information can be reconstructed with an
appropriate digital filter. The serial I/O can use a 5 V or a 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 AD7400A
is offered in a 16-lead SOIC and 8-lead gull-wing surface mount
DIP and has an operating temperature range of −40°C to
+125°C.
AC motor controls
Data acquisition systems
A/D + opto-isolator replacements
FUNCTIONAL BLOCK DIAGRAM
V_DD1
V_DD2
V_IN+
T/H
V_IN–
Σ-∆ ADC
BUF
REF
CONTROL LOGIC
UPDATE
ENCODE
UPDATE
AD7400A
WATCHDOG
DECODE
WATCHDOG
MDAT
ENCODE
DECODE
MCLKOUT
GND₁
Figure 1.
GND₂
1 _{Protected by U.S. Patents 5,952,849; 6,873,065; and 7,075,329. Other patents pending.}
Rev. PrA
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
www.analog.com
Fax: [phone]
©2008 Analog Devices, Inc. All rights reserved.