The BAS321 (commonly marked as A87 or A8) is a high-speed switching diode fabricated in planar technology and encapsulated in an ultra-compact SOD-323 (SC-76) surface-mount plastic package. Featuring a reverse breakdown voltage of 250V, low diode capacitance, and an ultra-fast reverse recovery time (t_rr) of 50ns, it is engineered for high-speed switching, signal isolation, and reverse polarity clamping in space-constrained electronic designs.

Specifications

• Brand / Manufacturer: Nexperia / ON Semiconductor / Diodes Inc. / Industry Standard
• Part Number / Marking: BAS321 / A87 / A8
• Diode Type: High-Speed Switching Diode
• Continuous Reverse Voltage (V_R): 200V (Maximum Continuous)
• Repetitive Peak Reverse Voltage (V_RRM): 250V
• Continuous Forward Current (I_F): 200mA to 250mA
• Non-Repetitive Peak Forward Surge Current (I_FSM): 1.7A (at t = 10ms half-sine) / 9.0A (at t = 1µs square)
• Forward Voltage Drop (V_F): < 1>F = 100mA / < 1>F = 200mA (at T_j = 25°C)
• Reverse Recovery Time (t_rr): Maximum 50ns (at I_F = 30mA, I_R = 30mA, I_rr = 3mA, R_L = 100Ω)
• Reverse Leakage Current (I_R): < 100nA>R = 200V (at T_j = 25°C) / < 100>j = 150°C
• Diode Capacitance (C_d): Maximum 2pF (at V_R = 0V, f = 1MHz)
• Total Power Dissipation (P_tot): Up to 500mW (at T_amb = 25°C)
• Operating Junction & Storage Temperature: -65°C to +150°C
• Package / Case: SOD-323 (SC-76) 2-Lead Surface Mount (Cathode marked with polarity bar)

Features

• High Reverse Voltage Blocking: Safely blocks reverse voltages up to 250V, making it ideal for higher voltage logic domains and mains-isolated secondary stages.
• Ultra-Fast Switching Speed: Fast 50ns recovery time ensures minimal switching distortion in high-frequency pulse and signal circuits.
• Low Junction Capacitance (2pF): Extremely low parasitic capacitance prevents signal degradation on high-speed digital and analog communication buses.
• Low Reverse Leakage: Keeps standby leakage current under 100nA, conserving power in battery-operated and energy-sensitive circuits.
• Compact SOD-323 Profile: Extremely small surface-mount package footprint optimizes board space in ultra-dense modern PCB layouts.

Common Applications

• High-Speed Signal Switching: Steering, routing, and isolating analog/digital signals in communication and microcontroller systems.
• Over-Voltage & Transient Clamping: Protecting sensitive IC input/output pins against electrostatic and inductive voltage spikes.
• Freewheeling for Small Inductive Loads: Suppressing kickback spikes across miniature relay coils, solenoids, and buzzers.
• Reverse Polarity Protection: Providing compact, reliable protection on low-current DC supply rails and battery inputs.
• General-Purpose Rectification: Low-current rectification in compact sensor modules and consumer electronics.

Usage Tips

• Cathode Identification: Verify correct PCB orientation before soldering; the laser-etched bar on the top of the SOD-323 package denotes the Cathode terminal.
• Current Limiting: Do not exceed the continuous forward current limit (200mA); use a series resistor when clamping or driving signal lines to limit current spikes.
• Parasitic Minimization: Place the diode as close as possible to the protected IC pin or connector to minimize stray trace inductance for optimal clamping performance.
• Soldering Precautions: Due to the miniature SOD-323 footprint, avoid prolonged contact with soldering irons to prevent package thermal shock (keep soldering time under 3 seconds per lead).

Datasheet