ISO7220A Datasheet, PDF (1/25 Pages) Texas Instruments – DUAL DIGITAL ISOLATORS

www.ti.com
ISO7220A, ISO7220C, ISO7220M
ISO7221A, ISO7221C, ISO7221M
SLLS755F – JULY 2006 – REVISED AUGUST 2007
DUAL DIGITAL ISOLATORS
FEATURES
• 1, 25, and 150-Mbps Signaling Rate Options
– Low Channel-to-Channel Output Skew;
1 ns max
– Low Pulse-Width Distortion (PWD);
1 ns max
– Low Jitter Content; 1 ns Typ at 150 Mbps
• Typical 25-Year Life at Rated Voltage
(see app. note SLLA197 and Figure 19)
• 4000-V_peak Isolation, 560 V peak V_IORM
– UL 1577, IEC 60747-5-2 (VDE 0884, Rev 2),
IEC 61010-1
– 50 kV/μs Typical Transient Immunity
• Operates with 3.3-V or 5-V Supplies
• 4 kV ESD Protection
• High Electromagnetic Immunity
• –40°C to 125°C Operating Range
APPLICATIONS
• Industrial Fieldbus
– Modbus
– Profibus™
– DeviceNet™ Data Buses
• Computer Peripheral Interface
• Servo Control Interface
• Data Acquisition
DESCRIPTION
The ISO7220 and ISO7221 are dual-channel digital isolators. To facilitate PCB layout, the channels are oriented
in the same direction in the ISO7220 and in opposite directions in the ISO7221. These devices have a logic
input and output buffer separated by TI’s silicon-dioxide (SiO₂) isolation barrier, providing galvanic isolation of up
to 4000 V. Used in conjunction with isolated power supplies, these devices block high voltage, isolate grounds,
and prevent 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 every 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.
The small capacitance and resulting time constant provide very fast operation with signaling rates available from
0 Mbps (DC) to 150 Mbps.⁽¹⁾The A- and C-option devices have TTL input thresholds and a noise filter at the
input that prevents transient pulses from being passed to the output of the device. The M-option devices have
CMOS Vcc/2 input thresholds and do not have the input noise-filter and the additional propagation delay.
These devices require two supply voltages of 3.3 V, 5 V, or any combination. All inputs are 5-V tolerant when
supplied from a 3.3-V supply and all outputs are 4-mA CMOS.
These devices are characterized for operation over the ambient temperature range of –40°C to 125°C.
ISO7220xD
ISO7221xD
V_CC1 ¹
INA ²
INB ³
GND1 ⁴
8 _VCC2
7 _OUTA
6 _OUTB
5 GND2
V_CC1 ¹
OUTA ²
INB ³
GND1 ⁴
8 _VCC2
7 _INA
6 _OUTB
5 GND2
(1) The signaling rate of a line is the number of voltage transitions that are made per second expressed in the units bps (bits per second).
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
DeviceNet is a trademark of Open DeviceNet Vendors Association.
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 © 2006–2007, Texas Instruments Incorporated