Diodes Selection Guide: Rectifier, Schottky, Zener, TVS — Key Specs and Popular Parts

Diodes Selection Guide: Rectifier, Schottky, Zener, TVS

Diodes are deceptively simple. But pick the wrong type and you'll see power supply failures, ESD damage, or a circuit that latches up — we've traced all three to a diode picked on price, not for the circuit.

Here's how to pick the right diode type for each application, with popular part numbers and Chinese alternatives.

Rectifier Diodes (Standard Recovery)

Best for: AC-to-DC conversion, reverse polarity protection, general switching

Key specs: Forward current (If), Reverse voltage (Vrrm), Surge current (Ifsm)

Forward voltage drop: ~1.0-1.1V

Reverse recovery time: ~2-5µs

Popular parts:

• 1N4007 (1A, 1000V) — the most common rectifier ever made
• 1N5408 (3A, 1000V)
• S1M (1A, 1000V, SMA package)

Chinese alternatives: GSIB, MSB series — over 60% of global rectifiers are now manufactured in China

Schottky Diodes

Best for: Low-voltage power supplies, OR-ing diodes, high-frequency switching

Key specs: Low forward voltage drop, fast recovery

Forward voltage drop: ~0.3-0.5V (much lower than standard rectifier)

Reverse recovery time: ~ps (effectively zero)

Popular parts:

• SS34 (3A, 40V, Schottky in SMC)
• 1N5819 (1A, 40V)
• BAT54 (200mA, 30V, dual in SOT-23)

Trade-off: Higher reverse leakage current than standard diodes. At 100°C, leakage can be 10x room-temperature value — this one catches people out in hot enclosures.

Chinese alternatives: SB3xx series, SK series

Zener Diodes

Best for: Voltage reference, voltage clamping, overvoltage protection

Key specs: Zener voltage (Vz), tolerance, power dissipation

Available voltages: 2.4V to 200V+ (E24 and E96 series)

Common applications:

• Voltage reference for ADC (use 0.5% tolerance zener or reference IC)
• Simple voltage regulator for low-current loads
• Protection against overvoltage on signal lines

Popular parts:

• BZX84C (300mW, SOT-23, various voltages)
• 1N47xx series (1W, DO-41)

Chinese alternatives: MM1Z series (SOD-123), MMSZ series (SOD-123)

TVS Diodes (Transient Voltage Suppression)

Best for: ESD protection, surge protection, lightning protection

Key specs: Standoff voltage (Vrwm), Breakdown voltage (Vbr), Peak pulse power (Ppp)

Response time: <1ns

Critical spec:

Vrwm must be higher than the maximum working voltage of the protected line.

Example: For 5V USB, use Vrwm = 5.0V or 5.5V.

Popular parts:

• P6KE series (600W, through-hole)
• SMBJ series (600W, SMD)
• USBLC6-2 (USB port protection)
• ESD9B5.0ST5G (ultra-low capacitance for high-speed data)

Fast Recovery Diodes

Best for: Switching power supplies, flyback diodes

Forward voltage: ~1.2-1.3V

Recovery time: 35-500ns

Use when: Schottky's voltage limit isn't high enough but standard rectifier is too slow

Quick Selection

References

• IPC Standards Library
• IEEE Xplore Digital Library