TEXAS INSTRUMENTS - ISO7220AD - DIGITAL ISOLATOR, 4KV, DUAL, SOIC8

TEXAS INSTRUMENTS - ISO7220ADRISO7220ADR - DIGITAL ISOLATOR, 4KV, DUAL, SOIC8

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 VPK. 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 ìs, 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 fast operation with signaling rates available from 0 Mbps (dc) to 150 Mbps.(1) The A-, B- 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.

Features:

• 1, 5, 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 )
• 4000-V_PK V_IOTM, 560 V_PK V_IORM
  per IEC 60747-5-2 (VDE 0884, Rev2)
• UL 1577, IEC 61010-1, IEC 60950-1 and CSA Approved
• 50 kV/µs Typical Transient Immunity
• Operates with 2.8-V (C-Grade), 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