ISO721-Q1 Datasheet, PDF (1/19 Pages) Texas Instruments – 3.3-V / 5-V HIGH-SPEED DIGITAL ISOLATORS

ISO721-Q1
www.ti.com ....................................................................................................................................................................................................... SLLS918 – JULY 2008
3.3-V / 5-V HIGH-SPEED DIGITAL ISOLATORS
FEATURES
1
• Qualified for Automotive Applications
• 4000-V_(peak) Isolation
– UL 1577, IEC 60747-5-2 (VDE 0884, Rev 2),
IEC 61010-1
– 50-kV/s Transient Immunity (Typ)
• Signaling Rate 0 Mbps to 150 Mbps
– Low Propagation Delay
– Low Pulse Skew
(Pulse-Width Distortion)
• Low-Power Sleep Mode
• High Electromagnetic Immunity
• Low Input Current Requirement
• Failsafe Output
• Drop-In Replacement for Most Optical and
Magnetic Isolators
DESCRIPTION
The ISO721 is a digital isolator with a logic input and output buffer separated by a silicon oxide (SiO₂) insulation
barrier. This barrier provides galvanic isolation of up to 4000 V. Used in conjunction with isolated power supplies,
this device prevents noise currents on a data bus or other circuits from entering the local ground, and interfering
with or damaging sensitive circuitry.
A binary input signal is conditioned, translated to a balanced signal, then differentiated by the capacitive isolation
barrier. Across the isolation barrier, a differential comparator receives the logic transition information, then sets or
resets a flip-flop and the output circuit accordingly. A periodic update pulse is sent across the barrier to ensure
the proper dc level of the output. If this dc refresh pulse is not received for more than 4 µs, the input is assumed
to be unpowered or not being actively driven, and the failsafe circuit drives the output to a logic high state.
FUNCTION DIAGRAM
Isolation Barrier
DC Channel
OSC
+
PWM
+
_
V_ref
_
+
Filter
Pulse Width
Demodulation
Carrier Detect
POR
BIAS
POR
Input
IN
+
Filter
AC Channel
+
_
V_ref
_
+
Data MUX
AC Detect
3-State
Output Buffer
OUT
1
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Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008, Texas Instruments Incorporated