ISO7421ED

Part: ISO7421EDR (ISO742x family) — Texas Instruments

Type: Dual-Channel Digital Isolator

Description: Low-power dual-channel digital isolator with signaling rates up to 50 Mbps, 3–5.5 V supplies, 2500 VRMS (UL 1577) / 4242 VPK (VDE) isolation, and 7 ns typical propagation delay. The ISO7421 has its two channels in opposite directions.

Operating Conditions:

• Supply voltage (VCC1, VCC2): 3.0–5.5 V
• Operating temperature (ambient): -40 to 125 °C
• Signaling rate: 0 to 50 Mbps
• Junction temperature: -40 to 136 °C
• Input pulse duration: min 20 ns
• Output current: IOH -4 mA (min), IOL 4 mA (max)

Absolute Maximum Ratings:

• Supply voltage VCC1, VCC2: -0.5 to 6 V
• Voltage at IN, OUT: -0.5 to VCC + 0.5 V
• Output current: ±15 mA
• Surge immunity (IEC 61000-4-5): 4000 VPK
• Max junction temperature: 150 °C
• Storage temperature: -65 to 150 °C
• ESD: HBM ±3000 V, CDM ±1500 V, MM ±200 V

Key Specs:

• VOH: ≥ VCCO - 0.8 V at IOH = -4 mA (4.6 V typ, 5 V supplies); ≥ VCCO - 0.1 V at IOH = -20 μA
• VOL: 0.4 V max at IOL = 4 mA; 0.1 V max at IOL = 20 μA (5 V supplies)
• Input threshold hysteresis: 400 mV typ
• Input current: IIH 10 μA max, IIL -10 μA min
• CMTI: 25 kV/μs min, 50 kV/μs typ (VI = VCCI or 0 V)
• Propagation delay: 7 ns typ; pulse skew: 200 ps typ
• Typical ICC per channel (ISO7421, 3.3 V supplies): 1.8 mA at 1 Mbps, 2.8 mA at 25 Mbps
• Isolation barrier life: > 25 years

Features:

• Signaling rate > 50 Mbps
• Default output high (no "F" suffix) or low ("F" suffix) on input power or signal loss
• 3.3 V and 5 V level translation
• TTL input thresholds; inputs 5 V tolerant with 3.3 V supply
• No integrated noise filter, giving fast propagation delay
• Safety approvals: VDE (DIN V VDE V 0884-10, DIN EN 61010-1), UL 1577, CSA, CQC (GB4943.1-2011)

Applications:

• Opto-coupler replacement in industrial fieldbus, ProfiBus, ModBus, DeviceNet data buses
• Servo control interface
• Motor control
• Power supplies
• Battery packs

Package:

• SOIC-8 (D), 4.90 mm x 3.91 mm nominal

• Opto-Coupler Replacement in:
• -Industrial FieldBus
• -ProfiBus
• -ModBus
• -DeviceNet™ Data Buses
• -Servo Control Interface
• -Motor Control
• -Power Supplies
• -Battery Packs

ISO742x provide galvanic isolation up to 2500 VRMS for 1 minute per UL and 4242 VPK per VDE. These devices have two isolated channels. Each channel has a logic input and output buffer separated by a silicon dioxide (SiO2) insulation barrier. Used in conjunction with isolated power supplies, these devices prevent noise currents on a data bus or other circuit from entering the local ground and interfering with or damaging sensitive circuitry. ISO7420 has both channels in the same direction while ISO7421 has the two channels in opposite direction. In case of input power or signal loss, default output is 'low' for devices with suffix 'F' and 'high' for devices without suffix 'F'. ISO742x have no integrated noise filter and thus have fast propagation delays.

These devices have TTL input thresholds and operate from 3-V to 5.5-V supplies. All inputs are 5-V tolerant when supplied from a 3.3-V supply.

TA = -40°C to 125°C

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ISO742x utilize single-ended TTL-logic switching technology. Its supply voltage range is from 3 V to 5.5 V for both supplies, VCC1 and VCC2. When designing with digital isolators, it is important to keep in mind that due to the single-ended design structure, digital isolators do not conform to any specific interface standard and are only intended for isolating single-ended CMOS or TTL digital signal lines. The isolator is typically placed between the data controller (i.e. μ C or UART), and a data converter or a line transceiver, regardless of the interface type or standard.