1N6489US-TR - 4.7V 1.5W Zener Diode D-5A | Microchip
MPN: 1N6489US-TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.5 | $7.50 |
| 10 | $6.45 | $64.50 |
| 100 | $5.2 | $520.00 |
| 500 | $4.1 | $2,050.00 |
| 1,000 | $3.35 | $3,350.00 |
1N6489US-TR Overview
A Zener diode is a specialized PN-junction diode engineered to operate in the reverse-bias breakdown region, where the voltage across the device remains nearly constant over a wide range of current. Zeners are widely used as shunt voltage regulators, voltage references, protection clamps, and waveform clippers across analog, power, and digital systems. In the broader component taxonomy, the 1N6489US-TR sits within discrete semiconductors → diodes → Zener diodes, and is one of the industry-recognized 1N64xx-series 1.5 W regulators from multiple defense-grade qualified vendors.
Key features include 1.5 W maximum power dissipation at 25 °C (derated linearly to 0 W at 200 °C), a nominal Zener voltage of 4.7 V at Izt = 53 mA, maximum Zener impedance of 8 Ω, low reverse leakage of 4 µA at 1 V VR, and a hermetically sealed glass MELF package. Operating junction and storage temperature range is -65 °C to +200 °C, with a thermal resistance suitable for typical PCB-mount thermal designs.
The 1N6489US-TR uses a hermetically sealed glass axial-leaded MELF construction that is mechanically robust and suitable for military and aerospace environments. Its precisely controlled breakdown voltage and tight tolerance make it a preferred choice for reference rails, ADC/DAC references, op-amp supply clamps, and overvoltage protection in sensitive analog front-ends.
Typical applications include precision voltage reference circuits, op-amp supply rail clamping, ADC/DAC reference buffering, overvoltage protection for analog input stages, and shunt regulation in industrial 24 V loop-powered instrumentation. The hermetic MELF construction also supports downhole, avionics, and military field-deployed equipment where reliability under thermal cycling is mandatory.
When designing with this Zener, ensure the working reverse current is well below the test current Izt so that the impedance does not rise excessively, and provide adequate PCB copper to dissipate up to 1.5 W continuous. For tighter tolerance requirements, series-characterize individual devices or consider a precision band-gap reference IC instead.
This page synthesizes distributor pricing, drop-in alternatives in the same D-5A MELF footprint, and practical design considerations that are not collected together in the manufacturer datasheet.
Drop-in alternatives for 1N6489US-TR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with 1N6489US-TR (same form factor and footprint) — differing in Maximum Power Dissipation (Pd), Maximum Zener Impedance (Zzt), Reverse Leakage Current (Ir).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
1N6489US
✅ Drop-In✓ In Stock
$8.1 / Unit
View Datasheet →JANTX1N6489US
✅ Drop-In📋 Reference alternative (not in catalog)
CDLL6489
✅ Drop-In📋 Reference alternative (not in catalog)
1N6489US-e3
✅ Drop-In📋 Reference alternative (not in catalog)
CDLL6489
✅ Drop-In📋 Reference alternative (not in catalog)
1N6489US-TR Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Product Type | Zener Diode (Voltage Regulator) |
| Nominal Zener Voltage (Vz) | 4.7 V |
| Zener Voltage Tolerance | ±5% |
| Maximum Power Dissipation (Pd) | 1.5 W at 25 °C |
| Maximum Zener Impedance (Zzt) | 8 Ω at Izt |
| Test Current (Izt) | 53 mA (typical) |
| Reverse Leakage Current (Ir) | 4 µA at VR = 1 V |
| Package / Case | D-5A (SQ-MELF, glass, hermetic) |
| Mounting Type | Surface Mount |
| Operating Junction Temperature | -65 °C to +200 °C |
| Storage Temperature | -65 °C to +200 °C |
| Military Qualification | MIL-PRF-19500/406 |
| Packaging | Tape & Reel (TR) |
1N6489US-TR Pin Configuration
| Pin 1 | Cathode — Cathode terminal (Zener reverse-bias operation when biased positive) |
| Pin 2 | Anode — Anode terminal (opposite cathode-marked end) |
Typical Applications
1N6489US-TR is suitable for 6 applications: Precision Voltage Reference Circuit, Op-Amp Supply Rail Clamping, ADC/DAC Reference Buffer Front-End, Overvoltage Protection for Analog Inputs, Shunt Regulation in 24 V Industrial Loops, Military and Aerospace Avionics Power Conditioning.
Precision Voltage Reference Circuit
The 1N6489US-TR delivers a 4.7 V nominal reference suitable for low-noise analog references when biased at Izt = 53 mA. Its 8 Ω maximum Zener impedance minimizes voltage drift versus current, while the hermetic D-5A MELF package eliminates thermal hysteresis typical of plastic Zeners. In a typical shunt reference design, the 1N6489US-TR sits between a current-source resistor and ground, producing a clean 4.7 V rail. Compared with a precision bandgap reference IC, this Zener is more rugged against input overvoltage events and tolerates wider temperature excursions.
Recommended
Op-Amp Supply Rail Clamping
Placed from each op-amp supply pin to ground, the 1N6489US-TR clamps transients to 4.7 V and protects sensitive analog front-ends from overvoltage events on ±5 V rails. With 1.5 W power dissipation and 8 Ω Zzt, it handles fast ESD-like spikes far better than small-signal TVS diodes of similar voltage. The hermetic MELF construction is preferred for industrial op-amp boards where reliability under thermal cycling from -65 °C to +200 °C matters.
Recommended
ADC/DAC Reference Buffer Front-End
The 1N6489US-TR can serve as a low-cost reference element in front of an ADC/DAC reference pin when system accuracy requirements are moderate (8-10 bit). Its 4.7 V nominal Zener voltage pairs naturally with 5 V supply rails, and the 4 µA leakage at 1 V reverse bias keeps idle current low. Designers typically buffer the Zener with a low-noise op-amp to drive the ADC reference pin directly, achieving a stable analog supply without the cost of a dedicated bandgap IC.
Recommended
Overvoltage Protection for Analog Inputs
Used as a shunt clamp on the input of an analog front-end, the 1N6489US-TR limits overvoltage transients to 4.7 V and dissipates up to 1.5 W of fault energy. This protects downstream op-amps, ADCs, and instrumentation amplifiers from surge events on field wiring. Combined with a series input resistor, it forms a two-stage protection network for 4-20 mA loops and other harsh-environment analog signals, particularly in industrial process-control and downhole applications.
Recommended
Shunt Regulation in 24 V Industrial Loops
In 24 V industrial loop-powered systems, the 1N6489US-TR can be combined with a series resistor to form a simple shunt regulator, providing a stable 4.7 V local rail for sensor signal conditioning. The 1.5 W dissipation and 8 Ω Zzt deliver adequate regulation for low-power analog circuits, while the wide -65 °C to +200 °C operating range handles the thermal environment of factory-floor enclosures. Its hermetic MELF package tolerates conformal coating and potting compounds better than plastic packages.
Recommended
Military and Aerospace Avionics Power Conditioning
The MIL-PRF-19500/406 qualification of the 1N6489US series makes this Zener suitable for avionics and military power conditioning, where reference rails and clamping circuits must survive harsh thermal and mechanical environments. The hermetic D-5A MELF package provides the long-term reliability required for flight-grade hardware, and the 4.7 V nominal supports legacy 5 V analog subsystems. Mission-critical designs should select the JANTX-screened variant for full Group A/B/C test coverage.
Recommended
Recommended Products Summary
Engineering reference data for 1N6489US-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 1N6489US | JANTX1N6489US | CDLL6489 | 1N6489US-e3 | CDLL6489 (Microsemi) |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Vishay Intertechnology | Microsemi |
| Package | D-5A (SQ-MELF) | D-5A (SQ-MELF) - same | D-5A (SQ-MELF) - same | D-5A (SQ-MELF) - same | D-5A (SQ-MELF) - same | D-5A (SQ-MELF) - same |
| Nominal Zener Voltage | 4.7 V | 4.7 V | 4.7 V | 4.7 V | 4.7 V | 4.7 V |
| Power Dissipation | 1.5 W | 1.5 W | 1.5 W | 1.5 W | 1.5 W | 1.5 W |
| Zener Impedance (Zzt) | 8 Ω max | 8 Ω max | 8 Ω max | 8 Ω max | 8 Ω max | 8 Ω max |
| Military Qualification | MIL-PRF-19500/406 (qualified) | MIL-PRF-19500/406 (qualified) | MIL-PRF-19500/406 + JANTX screening | MIL-PRF-19500/406 (qualified) | Not MIL-qualified | MIL-PRF-19500/406 (qualified) |
| Packaging Form | Tape & Reel (TR) | Bulk | Bulk | Bulk | Tape & Reel | Bulk |
| Operating Temperature | -65 °C to +200 °C | -65 °C to +200 °C | -65 °C to +200 °C | -65 °C to +200 °C | -65 °C to +200 °C | -65 °C to +200 °C |
Key Differentiators
- Military-qualified hermetic MELF construction (vs Generic 4.7 V plastic MELF Zeners (e.g., BZT52 series))
- Tape-and-reel factory packaging (vs 1N6489US (bulk))
- Tight 4.7 V Zener voltage in standard 1N64xxUS family (vs Custom-voltage specialty Zeners)
Design Notes
At 1.5 W continuous dissipation the junction temperature will rise substantially. With a typical θJA of approximately 100 °C/W on a standard PCB footprint, the junction-to-ambient rise is around 150 °C, which is well above the 200 °C maximum rating when ambient is near 25 °C. Provide at least 200 mm² of 2 oz copper pad area around the MELF terminations, or use thermal vias to an internal copper plane, to keep Tj below the derating curve. At higher ambient (>75 °C) or in enclosed housings, derate to 0.75 W or less.
Use wrap-around MELF land patterns per IPC-7352 with approximately 5 mm × 2.5 mm pads. Avoid placing tall components adjacent to the MELF body to allow automated optical inspection of the cathode band marking. For high-current or pulse applications, increase the cathode-side pad area to improve thermal spreading. Reflow profiles should follow JEDEC J-STD-020 for surface-mount glass-package devices, with peak temperature not exceeding 260 °C for lead-free assembly.
Do not confuse the 1N6489US (surface-mount MELF) with the 1N6489 (axial leaded) - they share the same electrical ratings but are not interchangeable on a populated PCB. Do not exceed 1.5 W dissipation without proper thermal management, as this MELF package has limited heat-sinking capability. Finally, do not operate below Izt for stable voltage reference applications, as Zzt rises sharply at low currents and the Zener voltage will droop significantly.
Compliance Information
MIL-PRF-19500/406 qualified per Microchip/Microsemi datasheet. RoHS, REACH, lead-free, and halogen-free compliance status not explicitly stated in provided web data and marked [DATA_NEEDED] accordingly. AEC-Q100 not applicable - this is a discrete Zener diode, not an automotive-qualified IC.
