1N6489US - 4.7V 1.5W Zener Diode SQ-MELF | Microchip
MPN: 1N6489US ✓ Hoạt động1N6489US Tóm tắt
A Zener diode is a specialized silicon pn-junction diode engineered to operate in the reverse-breakdown (Zener) region, where it maintains a near-constant voltage across its terminals despite variations in current. This makes Zener diodes the canonical building block for voltage reference, voltage regulation, and overvoltage protection circuits in analog and mixed-signal designs. The 1N6489US occupies the low-voltage end of the 1N6469-1N6491 family, with a 4.7 V nominal Zener voltage that is commonly used as a logic-rail reference (5 V systems with allowance for tolerance), A/D and D/A reference, and instrument-amplifier bias.
Key specifications include a nominal Zener voltage (Vz) of 4.7 V ±5%, maximum Zener impedance (Zzt) of 8 Ω at the test current, maximum reverse leakage (Ir) of 4 µA at 1 V reverse bias, and a maximum power dissipation of 1.5 W at 25 °C ambient with proper thermal mounting. The hermetically sealed SQ-MELF (US-suffix) package provides MIL-PRF-19500/406 qualification for military and aerospace applications, distinguishing it from the axial-leaded DO-41 (non-US) variant of the same die.
The 1N6489US uses a glass-passivated silicon junction die bonded in a hermetic metal-glass envelope, yielding long-term stability and low reverse leakage. The 8 Ω maximum Zener impedance ensures tight voltage regulation even at low Zener currents, making the part suitable for low-noise reference designs. The MIL-PRF-19500/406 qualification and hermetic construction deliver the reliability expected in defense, avionics, and space-grade power subsystems.
Typical applications include 5 V system voltage references, op-amp supply rails, A/D and D/A converter references, overvoltage clamps on signal lines, and military/aerospace power-conditioning circuits. The 1.5 W rating also makes it usable as a low-power shunt regulator in distributed power systems.
When designing with the 1N6489US, ensure the PCB land pattern matches the SQ-MELF (A-MELF) footprint, which differs from the axial DO-41 of the non-US 1N6489. Provide adequate copper thermal area on both anode and cathode pads; derate to 0.8 W or less above 75 °C ambient. Use a series current-limiting resistor sized so that Iz stays within the datasheet test-current window to guarantee the 4.7 V regulation point.
This page synthesizes Microchip/Microsemi distributor pricing, MIL-spec qualification details, drop-in alternatives in the same SQ-MELF footprint, and practical thermal design notes not consolidated in the manufacturer datasheet alone.
Bộ thay thế dễ dàng lắp đặt cho 1N6489US — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với 1N6489US (cùng hình factor và footprint) — khác nhau ở Maximum Power Dissipation (Pd), Maximum Zener Impedance (Zzt), Reverse Leakage Current (Ir).
1N6489US
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →CDLL6489
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
1N4732A
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
BZX84C4V7LT1G
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MMSZ5221BT1G
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
1N6489US Tỷ lệ tối đa & tính chất điện
| Zener Voltage (Nominal, Vz) | 4.7 V |
| Zener Voltage Tolerance | ±5% |
| Maximum Power Dissipation (Pd) | 1.5 W |
| Maximum Zener Impedance (Zzt) | 8 Ω |
| Reverse Leakage Current (Ir) | 4 µA at 1 V |
| Hộp | SQ-MELF (A-MELF), surface mount |
| Kiểu lắp đặt | Surface Mount |
| Khoảng nhiệt độ hoạt động | -65 °C to +175 °C (military grade) |
| Military Qualification | MIL-PRF-19500/406 |
| Diode Type | Zener voltage regulator |
| Configuration | Single |
| Polarity | Cathode band marked |
| Construction | Hermetically sealed glass |
| Trạng thái RoHS | Compliant |
| Lead-Free | Yes |
Cấu hình chân 1N6489US
| Chân 1 | Anode (A) — Anode terminal (positive) |
| Chân 2 | Cathode (K) — Cathode terminal (negative, banded end) |
Ứng dụng tiêu biểu
1N6489US phù hợp cho 6 Áp dụngs: 5 V Logic-Rail Voltage Reference, ADC/DAC Reference Bias, Overvoltage Protection Clamp, Military and Avionics Power Conditioning, Op-Amp Supply Rail Reference, Industrial Process Control Signal Conditioning.
5 V Logic-Rail Voltage Reference
The 1N6489US's 4.7 V ±5% Zener voltage sits naturally below the 5 V TTL/CMOS rail, providing a stable reference that can be biased from the 5 V supply through a current-limiting resistor. With 8 Ω maximum Zener impedance and 4 µA reverse leakage, the 1N6489US holds the reference within a few millivolts under load steps in instrumentation and logic-level translation circuits. The MIL-PRF-19500/406 qualification also makes it suitable for defense electronics where long-term reference stability is critical.
Được đề xuất
ADC/DAC Reference Bias
Precision analog-to-digital and digital-to-analog converters require low-impedance reference voltages to maintain linearity. The 1N6489US, with its 8 Ω maximum Zener impedance and ±5% tolerance, can serve as a coarse reference or as the bias point for a precision op-amp reference buffer. The hermetic SQ-MELF glass package minimizes moisture-driven drift, which is essential in test-and-measurement equipment where calibration stability over years matters.
Được đề xuất
Overvoltage Protection Clamp
In signal-line protection circuits, the 1N6489US can clamp transient overvoltages to its 4.7 V Zener voltage when reverse-biased into breakdown by an ESD or inductive kick event. Its 1.5 W power rating allows the part to absorb multi-millisecond transients that would damage downstream CMOS logic. Used as a secondary protector behind a TVS diode, the 1N6489US adds a hard voltage ceiling for 5 V logic interfaces in industrial control and avionics bays.
Được đề xuất
Military and Avionics Power Conditioning
The MIL-PRF-19500/406 qualification makes the 1N6489US directly usable in military and avionics power subsystems where screened, hermetic components are mandatory. It is commonly deployed as a low-voltage shunt regulator in 28 V aircraft power buses, providing a stable 4.7 V reference for indicator lamps, relay logic, and sensor excitation. The wide -65 °C to +175 °C operating range covers both cockpit and unpressurized avionics bay environments.
Được đề xuất
Op-Amp Supply Rail Reference
Bipolar op-amps that require asymmetric supplies (e.g., +12 V and -4.7 V) can use the 1N6489US to derive the negative rail from a positive bias through a shunt regulator topology. The 8 Ω Zener impedance and 1.5 W rating accommodate typical op-amp quiescent currents while keeping the rail within ±5% across temperature. The hermetic SQ-MELF package suits industrial and instrumentation amplifier designs requiring long-term rail stability.
Được đề xuất
Industrial Process Control Signal Conditioning
In 4-20 mA current loops and other industrial process-control signal paths, the 1N6489US can serve as a low-voltage Zener reference for transducer excitation or as a clamp on field-wiring inputs. Its 1.5 W dissipation handles the transient energy from cable discharge events, and the SQ-MELF surface-mount package fits compact DIN-rail-mounted controller PCBs. The MIL-PRF-19500/406 screening also makes it a candidate for safety-rated industrial systems.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho 1N6489US — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | 1N6489US (Microsemi line) | CDLL6489 | 1N4732A | BZX84C4V7LT1G | MMSZ5221BT1G |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | onsemi | onsemi |
| Package | SQ-MELF (A-MELF) | SQ-MELF (A-MELF) - same | SQ-MELF (A-MELF) - same | DO-41 axial - different footprint | SOT-23 - different footprint | SOD-123 - different footprint |
| Zener Voltage (Nominal) | 4.7 V | 4.7 V | 4.7 V | 5.1 V | 4.7 V | 2.4 V |
| Power Dissipation | 1.5 W | 1.5 W | 1.5 W | 1 W | 225 mW | 500 mW |
| Zener Impedance (Zzt) | 8 Ω max | 8 Ω max | 8 Ω max | 10 Ω max | 70 Ω max | 30 Ω max |
| Tolerance | ±5% | ±5% | ±5% | ±5% (A suffix) | ±5% | ±5% |
| Military Qualification | MIL-PRF-19500/406 | MIL-PRF-19500/406 | DESC drawing screened | Not MIL-qualified | Not MIL-qualified | Not MIL-qualified |
| Operating Temperature Range | -65 °C to +175 °C | -65 °C to +175 °C | -65 °C to +175 °C | -65 °C to +175 °C | -55 °C to +150 °C | -55 °C to +150 °C |
Bảo phân biệt quan trọng
- Hermetic MIL-PRF-19500/406 SQ-MELF surface-mount Zener (vs1N4732A (DO-41 axial))
- 1.5 W power dissipation in SQ-MELF (vsBZX84C4V7LT1G (SOT-23))
- 4.7 V ±5% with 8 Ω maximum Zener impedance (vsMMSZ5221BT1G (SOD-123))
Ghi chú thiết kế
Estimated: at 1.5 W dissipation in the SQ-MELF glass package, the junction-to-ambient thermal resistance (θJA) requires at least 100 mm² of copper thermal pad on both anode and cathode lands. Without this thermal area the part will derate below 1 W well before reaching the 175 °C military upper temperature limit. Always verify junction temperature under worst-case (minimum series resistance, maximum Zener current) operating conditions.
The SQ-MELF (A-MELF) land pattern requires MELF-style round or oval pads with the cathode band matching the datasheet mechanical outline. Do not use the SOD-123 footprint - the body diameter is larger and the pad spacing is wider. For wave soldering, follow the J-STD-020 MSL profile; the hermetic glass package is moisture-insensitive but the surface-mount finish still requires standard handling.
Do not confuse the surface-mount 1N6489US (SQ-MELF) with the through-hole 1N6489 (DO-41 axial). They share the same die and 4.7 V rating but use different footprints; PCB rework is required to swap them. Also confirm the series resistor value: at the datasheet test current the Zener holds 4.7 V, but at currents far below the test point the Zener impedance rises and the regulation point shifts - this is the most common cause of 'Zener voltage is wrong' field complaints.
Thông tin tuân thủ
RoHS and REACH compliant per Microchip product page. MIL-PRF-19500/406 qualified for military and aerospace use. AEC-Q100 not applicable - this is a discrete Zener diode, not an automotive-qualified IC; for automotive applications consult Microchip's automotive-grade Zener portfolio.
