ISO7221B - Dual Channel, 1/1, 5Mbps Digital Isolator

The ISO7220x and ISO7221x family devices are dual-channel digital isolators. Tofacilitate PCB layout, the channels are oriented in the same direction in the ISO7220x and inopposite directions in the ISO7221x. These devices have a logic input and output buffer separatedby TI’s silicon-dioxide (SiO₂) isolation barrier, providing galvanicisolation of up to4000V_PK per VDE. Used in conjunction with isolated power supplies, these devicesblock high voltage and isolate grounds, as well as prevent noise currents on a data bus or othercircuits from entering the local ground and interfering with or damaging sensitivecircuitry.

A binary input signal is conditioned, translated to a balanced signal, thendifferentiated by the capacitive isolation barrier. Across the isolation barrier, a differentialcomparator receives the logic transition information, then sets or resets a flip-flop and theoutput circuit accordingly. A periodic update pulse is sent across the barrier to ensure the properdc level of the output. If this dc-refresh pulse is not received every 4 µs, the input is assumedto be unpowered or not being actively driven, and the failsafe circuit drives the output to a logichigh state.

The small capacitance and resulting time constant provide fast operation with signalingrates available from 0 Mbps (DC) to 150 Mbps (The signaling rate of a line is the number of voltagetransitions that are made per second expressed in the units bps). The A-option, B-option, andC-option devices have TTL input thresholds and a noise filter at the input that prevents transientpulses from being passed to the output of the device. The M-option devices have CMOSV_CC/2 input thresholds and do not have the input noise filter and theadditional propagation delay.

The ISO7220x and ISO7221x family of devices require two supply voltages of 2.8 V(C-Grade), 3.3 V, 5 V, or any combination. All inputs are 5-V tolerant when supplied from a 2.8-Vor 3.3-V supply and all outputs are 4-mA CMOS.

The ISO7220x and ISO7221x family of devices are characterized for operation over theambient temperature range of –40°C to +125°C.

• 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
• 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
• Typical 28-Year Life at Rated Voltage
  (see High-Voltage Lifetime of the ISO72x Family of Digital Isolators and Isolation Capacitor Lifetime Projection)
• Safety-Related Certifications
  • VDE Basic Insulation with 4000-V_PK V_IOTM, 560 V_PK V_IORM per DIN VDE V 0884-11:2017-01 and DIN EN 61010-1 (VDE 0411-1)
  • 2500 V_RMS Isolation per UL 1577
  • CSA Approved for IEC 60950-1 and IEC 62368-1

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