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

Diodes Selection Guide: Rectifier, Schottky, Zener, TVS

Diodes are deceptively simple — but choosing the wrong type causes power supply failures, ESD damage, and circuit latch-up.

Here's how to select 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.

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