GDZJ30B - 30V 500mW Zener Diode DO-34 | Pan Jit
MPN: GDZJ30B ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.18 | $0.18 |
| 10 | $0.14 | $1.40 |
| 100 | $0.09 | $9.00 |
| 500 | $0.07 | $35.00 |
| 1,000 | $0.05 | $50.00 |
| 5,000 | $0.04 | $200.00 |
GDZJ30B Overview
A Zener diode is a specialized silicon p-n junction diode engineered to operate stably in the reverse-breakdown (Zener) region, where it maintains a nearly constant voltage across a wide range of reverse currents. In circuit topology, Zener diodes belong to the discrete semiconductor family and function as primitive voltage references, voltage clamps, or simple shunt regulators. They are the lowest-cost implementation of a fixed reference and are widely used for secondary regulation, overvoltage protection, and signal limiting.
Key features of the GDZJ30B include a nominal Zener voltage (Vz) of 30 V at the standard test current (Iz), 500 mW maximum power dissipation at 25 °C ambient (derated linearly above this temperature), and a planar die construction that delivers predictable Zener voltage characteristics and low leakage. The DO-34 molded glass envelope provides hermetic sealing and is approximately 0.012 g per piece, making it suitable for high-density through-hole designs. Lead polarity is indicated on the body per the manufacturer diagram.
From an electrical perspective, the GDZJ30B exhibits a Zener impedance (Zzt) and reverse leakage current (Ir) consistent with the planar process technology. The 30 V nominal sits in the mid-range of the GDZJ series and is typically selected when a precision reference around 30 V is required for analog signal conditioning, instrumentation supply rails, or as a bias-voltage source for transistor circuits.
Typical applications include voltage reference for analog front-end circuits, overvoltage protection for instrumentation inputs, and as a simple shunt regulator in industrial control and test & measurement equipment. Because of its DO-34 through-hole package, it is most commonly used in legacy through-hole PCB designs, prototyping, and repair/replacement scenarios rather than new high-density SMT boards.
When designing with the GDZJ30B, observe the 500 mW power dissipation ceiling and apply proper derating above 25 °C. Mount leads with strain relief to prevent glass-body fracture, and respect the reverse-leakage behavior when used as a precision source at low currents.
This page synthesizes verified distributor pricing, drop-in alternatives within the GDZJ series, and practical design notes not consolidated on a single manufacturer datasheet.
Drop-in alternatives for GDZJ30B — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
GDZJ27B
✅ Drop-In📋 Reference alternative (not in catalog)
GDZJ33B
✅ Drop-In📋 Reference alternative (not in catalog)
GDZJ36B
✅ Drop-In📋 Reference alternative (not in catalog)
GDZJ30B
✅ Drop-In✓ In Stock
$0.04 / Unit
View Datasheet →GDZJ30B-N
✅ Drop-In📋 Reference alternative (not in catalog)
GDZJ30B
✅ Drop-In✓ In Stock
$0.04 / Unit
View Datasheet →GDZJ30B Maximum Ratings & Electrical Characteristics
| Diode Type | Zener (Voltage Reference) |
| Nominal Zener Voltage (Vz) | 30 V |
| Voltage Tolerance | ±3% |
| Maximum Power Dissipation (Pd) | 500 mW at 25 °C |
| Package | DO-34 (Axial Lead, Molded Glass) |
| Mounting Type | Through-Hole (Axial) |
| Construction | Planar Die |
| Terminals | Solderable per MIL-STD-202, Method 208 |
| Polarity Indication | Marked on body per manufacturer diagram |
| Approximate Weight | 0.012 g |
| Configuration | Single (2-pin) |
| RoHS Status | Lead-free per EU RoHS 2002/95/EC directives |
| Lead-Free | Yes (per Pan Jit datasheet R2_10001) |
| Series | GDZJ (Axial Lead Zener) |
GDZJ30B Pin Configuration
| Pin 1 | Cathode — Band end - positive terminal when reverse-biased in Zener operation |
| Pin 2 | Anode — Unbanded end - negative terminal / ground reference in Zener operation |
Typical Applications
GDZJ30B is suitable for 7 applications: Voltage Reference for Analog Front-End, Overvoltage Clamping on 24V Industrial Lines, Simple Shunt Regulator for Sensor Bias, Test & Measurement Equipment Reference, Signal Limiter in Communication Circuits, Power Supply Crowbar Protection, Bias Voltage for Transistor and Op-Amp Circuits.
Voltage Reference for Analog Front-End
The GDZJ30B provides a stable 30 V reference for analog signal-conditioning circuits in instrumentation and data-acquisition systems. Its planar-die construction delivers predictable Zener voltage with low leakage, and biasing near the test current minimizes Zener impedance. Designers place it as a simple shunt reference biased by a series resistor; the 500 mW rating supports milliamps of standing current while remaining within thermal limits at industrial ambient temperatures up to 70 °C. Compared to active references, the GDZJ30B adds no quiescent overhead and tolerates wide supply variation, making it ideal for low-cost analog front-ends where sub-1% accuracy is acceptable.
Recommended
Overvoltage Clamping on 24V Industrial Lines
The GDZJ30B is widely used to clamp transients on 24 V industrial signal lines, PLC I/O channels, and sensor inputs. Its 30 V nominal sits just above the 24 V supply rail plus inductive kickback peaks, providing effective clamping for relay coils, solenoids, and motor wiring. The 500 mW rating limits continuous dissipation, so the designer must verify Zz × Iz remains within the derated Pd over the operating temperature. Mounting the diode close to the protected load and using a low-inductance ground return minimizes clamping voltage overshoot during fast transient events common in industrial environments.
Recommended
Simple Shunt Regulator for Sensor Bias
The GDZJ30B serves as a simple shunt regulator to bias sensors, transducers, and bridge circuits where a stable mid-voltage reference is required. Connecting the Zener cathode to the bias node through a series resistor and the anode to ground creates a low-cost regulator with predictable output voltage. The 30 V nominal is well suited to bias higher-voltage sensors and strain-gauge bridges; the planar die ensures repeatable Vz across production lots. For better load regulation, follow the Zener with an emitter-follower buffer; for tighter accuracy, use the GDZJ30B as a coarse pre-regulator ahead of a precision reference IC.
Recommended
Test & Measurement Equipment Reference
The GDZJ30B is commonly used as a calibration and reference element in test & measurement equipment, multimeters, and bench instruments. Its 30 V output provides a known reference for ADC self-calibration, linearity checks, and divider-ratio verification. The ±3% tolerance is acceptable for service-grade instruments; for laboratory-grade accuracy the device is paired with a precision buffer amplifier. The DO-34 through-hole package supports both manual-prototype construction and traditional instrument-assembly lines where axial-leaded components remain standard.
Recommended
Signal Limiter in Communication Circuits
The GDZJ30B functions as a signal limiter in communication line interfaces, particularly for protecting low-voltage transceivers from high-voltage line transients in legacy telecom and industrial bus circuits. Reverse-connecting the Zener between the signal line and ground clamps incoming transients to ±30 V, protecting downstream ESD-sensitive devices. The 500 mW rating is sufficient for periodic clamping events but not for sustained short-circuit conditions; designers should pair the Zener with a PTC fuse or current-limiting resistor for full protection.
Recommended
Power Supply Crowbar Protection
The GDZJ30B can serve as the trigger element in a simple crowbar protection circuit for 24 V power rails in industrial and embedded systems. When combined with an SCR or triac, the Zener's 30 V breakdown triggers the crowbar to short-circuit the supply during overvoltage, blowing the upstream fuse and protecting downstream loads. The 500 mW rating is more than adequate for the trigger role since the Zener only carries milliamps until the SCR latches. This architecture is well-proven in legacy industrial power designs where cost and simplicity outweigh active-monitoring alternatives.
Recommended
Bias Voltage for Transistor and Op-Amp Circuits
The GDZJ30B provides a stable bias voltage source for transistor and op-amp circuits requiring a fixed mid-rail reference. In discrete amplifier stages, current-mirror bias networks, and analog multipliers, a 30 V Zener reference establishes predictable operating points independent of supply variation. The planar process technology ensures repeatable Vz from device to device, simplifying matched-pair designs. For low-noise applications, the Zener should be bypassed with a 100 nF ceramic capacitor at the bias node to filter broadband noise generated by the avalanche breakdown mechanism.
Recommended
Recommended Products Summary
Engineering reference data for GDZJ30B — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | GDZJ27B | GDZJ33B | GDZJ36B | GDZJ30B (Shunye) | GDZJ30B-N |
|---|---|---|---|---|---|---|
| Brand | Pan Jit International | Pan Jit International | Pan Jit International | Pan Jit International | Shanghai Shunye | WILLAS |
| Package | DO-34 | DO-34 - same | DO-34 - same | DO-34 - same | DO-34 - same | DO-34 - same |
| Nominal Zener Voltage (Vz) | 30 V | 27 V | 33 V | 36 V | 30 V | 30 V |
| Voltage Tolerance | ±3% | ±3% | ±3% | ±3% | ±3% | ±3% |
| Power Dissipation | 500 mW | 500 mW | 500 mW | 500 mW | 500 mW | 500 mW |
| Mounting Type | Through-Hole (Axial) | Through-Hole (Axial) | Through-Hole (Axial) | Through-Hole (Axial) | Through-Hole (Axial) | Through-Hole (Axial) |
Key Differentiators
- Multi-source availability reduces supply-chain risk (vs Single-source 30V Zeners)
- Planar die construction delivers predictable Vz (vs Alloy-junction 30V Zeners)
- RoHS-compliant lead-free construction (vs SnPb-leaded Zeners)
Design Notes
The 500 mW power rating applies at 25 °C ambient and must be derated linearly to zero at the maximum junction temperature. Estimated: at 70 °C industrial ambient, allowable dissipation is approximately 300 mW. Verify Zz × Iz (steady-state) plus transient clamping energy (single-pulse) stays within the derated Pd, since continuous operation near 500 mW at elevated temperature will shorten service life.
Mount the GDZJ30B with adequate strain relief on the leads to prevent glass-body cracking during thermal cycling or mechanical shock. Keep lead-bends at least 1.5 mm away from the glass body. For through-hole PCB assembly, ensure hole diameter accommodates the 0.5–0.6 mm typical lead diameter and that wave-solder dwell does not thermally fracture the package.
Do not use the GDZJ30B as a substitute for a precision voltage reference when the design requires sub-1% accuracy; the ±3% tolerance is suitable for clamping and biasing but not for ADC reference rails. Do not exceed 500 mW continuous dissipation - peak clamping events must be averaged to verify thermal limits. Always verify Zener polarity before installation (banded end = cathode) to avoid reverse-mount failures.
Zener diodes generate broadband avalanche noise; for low-noise analog applications, bypass the GDZJ30B with a 100 nF ceramic capacitor at the reference node to filter high-frequency noise. For very low-noise reference requirements, follow the Zener with an emitter-follower buffer or use a dedicated low-noise reference IC such as the TL431 or ADR01 series instead.
Compliance Information
RoHS compliance per Pan Jit datasheet (GDZJ30B_R2_10001) - Lead free in comply with EU RoHS 2002/95/EC directives. REACH, halogen-free, and conflict-mineral status not specified in aggregated datasheet - request manufacturer compliance certificate for full status. Not AEC-Q100 qualified - this part is designed for general-purpose industrial/consumer use, not automotive.
