2N4037 - 40V PNP Power BJT Transistor | Central Semiconductor
MPN： 2N4037 ✓ 啟用中2N4037 概覽
An PNP bipolar junction transistor is a three-terminal semiconductor device in which a p-type emitter, n-type base, and p-type collector form two back-to-back p-n junctions. Conventional current flows from emitter to collector when the base is pulled below the emitter potential, and the device operates in the active region when the base-emitter junction is forward-biased and the base-collector junction is reverse-biased. PNP BJTs are commonly used as low-side switches, complementary-symmetry push-pull amplifiers (paired with NPN devices), and level shifters in mixed-polarity analog circuits. The 2N-series designation historically indicates a JEDEC-registered part number with widely shared specifications across manufacturers.
Key features of the 2N4037 include a maximum collector-base voltage of 60V, a maximum emitter-base voltage of 7V, a power dissipation rating of 1W (to 25°C case), DC current gain (hFE) typically 40 to 250 depending on collector current, and a transition frequency (fT) of approximately 60 MHz. The TO-39 metal package provides hermetic sealing suitable for military, aerospace, and industrial environments, with three through-hole leads (emitter, base, collector) on standard EIA lead spacing.
The architecture is an epitaxial planar PNP silicon construction, a manufacturing approach where a thin epitaxial layer is grown on the silicon substrate to control minority carrier lifetime and improve switching characteristics versus older alloy-junction designs. The planar passivation process yields stable leakage and gain over temperature, supporting operation from -65°C to +200°C as typical for the TO-39 metal-can family.
Typical applications include general-purpose linear amplifiers, low-frequency switching circuits, complementary-symmetry audio output stages paired with 2N4036 NPN, driver stages for relays and solenoids, voltage regulators, and current sources. The 1W dissipation rating supports small signal-amplifier and modest driver use; high-current applications require discrete heatsinking or the use of a TO-220 equivalent.
When designing with this part, verify the pinout against the datasheet (TO-39 pin order varies by manufacturer and by family). The TO-39 case must be considered in the thermal budget - at 1W dissipation the case-to-ambient thermal resistance typically requires derating above 25°C ambient, and a small clip-on heatsink or thermal compound to chassis is recommended for continuous full-load operation.
This page synthesizes distributor pricing, drop-in alternatives, pinout notes, and practical design guidance not consolidated in the manufacturer datasheet, providing actionable engineering context for component selection.
直接替換替代品，適用於 2N4037 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： 2N4037 （相同外形與佔位） — 差異在於 Continuous Collector Current (Ic), Emitter-Base Voltage (Vebo), Transistor Type, Transition Frequency (fT).
2N5323
✅ 直接替換📋 參考替代品（不在目錄中）
2N4036
✅ 直接替換📋 參考替代品（不在目錄中）
BC160
✅ 直接替換📋 參考替代品（不在目錄中）
BC161
✅ 直接替換📋 參考替代品（不在目錄中）
2N4037 PBFREE
✅ 直接替換📋 參考替代品（不在目錄中）
2N4037 最大額定值與電氣特性
| 電晶體類型 | PNP Bipolar Junction Transistor |
| Material | Silicon (Si), epitaxial planar |
| Polarity | PNP |
| 集極-基極電壓 (Vcbo) | 60 V |
| 集極-射極電壓 (Vceo) | 40 V |
| 射極-基極電壓 (Vebo) | 7 V |
| Continuous Collector Current (Ic) | 1 A |
| Power Dissipation (Pc) | 1 W (TO-39 case, 25°C) |
| 轉換頻率 (ft) | 60 MHz (typical) |
| DC Current Gain (hFE) | 40-250 (depending on Ic) |
| 工作溫度範圍 | -65°C to +200°C |
| 封裝 | TO-39 (TO-205AD) metal can, 3-pin through-hole |
| 安裝類型 | Through Hole |
| Configuration | Single transistor, 3 leads (E, B, C) |
| Compliance | RoHS variant available (PBFREE suffix); TIN/LEAD variant also offered |
2N4037 腳位配置
| 腳位 1 | Emitter — Emitter terminal (E) |
| 腳位 2 | Base — Base terminal (B) - control input |
| 腳位 3 | Collector — Collector terminal (C) and case |
典型應用
2N4037 適用於 7 應用s: Complementary-Symmetry Audio Output Stage, Linear Small-Signal Amplifier, Relay and Solenoid Driver, Voltage Regulator Pass Element, Switching Circuit and Signal Conditioning, Current Source and Current Mirror, Legacy and Vintage Equipment Repair.
Complementary-Symmetry Audio Output Stage
The 2N4037 paired with its NPN complement 2N4036 forms a classic complementary-symmetry push-pull output stage for low-power audio amplifiers. The 2N4037's 40V Vceo and 1A continuous collector current suit single-ended Class A or Class AB stages driving a few hundred milliwatts into an 8-ohm speaker. With fT of 60 MHz the device provides ample bandwidth for the audio band and significantly beyond, while the TO-39 metal can offers mechanical ruggedness for hand-wired vintage audio projects and the hermetic seal supports tube-amp-style chassis-mounted builds.
推薦
Linear Small-Signal Amplifier
The 2N4037 is well suited as a general-purpose linear amplifier in industrial instrumentation and control circuits. Its DC current gain hFE of 40-250 supports stable biasing in common-emitter or common-collector (emitter-follower) configurations, and its 60V collector-base rating provides significant headroom over the 40V Vceo, allowing inductive kickback transients in relay coils. The hermetic TO-39 package stands up to factory-floor temperature cycling and airborne contamination that would degrade plastic-packaged alternatives, supporting long-life industrial deployments.
推薦
Relay and Solenoid Driver
The 2N4037's 1A continuous collector current makes it an effective low-side driver for relays, solenoids, and small DC motors in industrial control. With its 40V Vceo it can switch 24V industrial rails through inductive loads comfortably, providing margin for flyback transients when paired with a freewheeling diode. The PNP polarity is convenient when the driver must be referenced to a positive supply rail, and the TO-39 metal package supports chassis-mounted thermal bonding for sustained 1W dissipation at high duty cycles.
推薦
Voltage Regulator Pass Element
In discrete linear voltage regulators and shunt references the 2N4037 can serve as the series pass element when paired with a Zener reference and an error amplifier. The 40V Vceo handles raw 24V industrial bus inputs with substantial margin, and the 1A collector current supports moderate-current regulation for analog subsystems. The PNP polarity suits low-dropout regulator topologies in which the pass element sits between the unregulated input and the regulated output with the emitter delivering current to the load.
推薦
Switching Circuit and Signal Conditioning
The 2N4037 is frequently used as a saturated or unsaturated switch in logic-level translation circuits, level shifters, and analog gating stages. With fT of 60 MHz it offers substantially more bandwidth than switching applications strictly require, making it well suited to high-speed analog multiplexers and sample-and-hold front-ends. The hermetic TO-39 package also supports test-and-measurement equipment that must survive years of bench-side thermal cycling.
推薦
Current Source and Current Mirror
The matched-pair characteristics of the 2N4037 (when sourced as a complementary 2N4036/2N4037 set) make it a useful building block for discrete current mirrors and precision current sources. The hFE linearity over collector current supports Wilson and Widlar mirror topologies, and the 40V Vceo allows operation across wide compliance ranges. Such mirrors are commonly used in biasing circuits for op-amps and precision references, where the matched NPN/PNP pair from a single-die complementary process minimizes offset.
推薦
Legacy and Vintage Equipment Repair
The 2N4037 remains a popular replacement part for repairing vintage analog electronics - tube amplifier front ends, 1970s-era instrument preamplifiers, and classic ham-radio transmitter stages. The TO-39 metal can is a direct mechanical match for original 2N-series sockets, and the part is broadly second-sourced, so repair technicians can maintain period-correct builds without resorting to plastic-packaged modern equivalents. Its tolerance to high ambient temperatures inside chassis-mounted equipment also makes it durable in service.
推薦
推薦產品摘要
工程參考資料，適用於 2N4037 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | 2N5323 | 2N4036 | BC160 | BC161 | 2N4037 PBFREE |
|---|---|---|---|---|---|---|
| Brand | Central Semiconductor | Multiple (2N-series) | Central Semiconductor | Multiple (BC-series) | Multiple (BC-series) | Central Semiconductor |
| Package | TO-39 (TO-205AD) | TO-39 | TO-39 | TO-39 | TO-39 | TO-39 |
| Polarity | PNP | PNP | NPN | PNP | PNP | PNP |
| Vceo | 40 V | 50 V | 40 V | 40 V | 60 V | 40 V |
| Vcbo | 60 V | 75 V | 60 V | 40 V | 60 V | 60 V |
| Ic (Continuous) | 1 A | 2 A | 1 A | 1 A | 1 A | 1 A |
| Power Dissipation | 1 W | 5 W | 1 W | 3.7 W | 3.7 W | 1 W |
| fT (Transition Frequency) | 60 MHz | 30 MHz | 60 MHz | 50 MHz | 50 MHz | 60 MHz |
| RoHS Compliance | Pb-free variant available | Pb-free variant available | Pb-free variant available | Varies by manufacturer | Varies by manufacturer | Yes (RoHS compliant) |
主要差異化特點
- Hermetic TO-39 metal can package availability in production (對比BC160 (plastic package))
- Documented complement pairing on a single datasheet (對比2N5323 (no documented complement))
- Lead-free RoHS-compliant option from a long-established manufacturer (對比BC161 (varying compliance by source))
設計說明
The TO-39 metal can has a junction-to-ambient thermal resistance of approximately 195°C/W without a heatsink. At the full 1W dissipation rating the junction-to-case rise is roughly 75°C, so case temperature must remain below 150°C to keep the junction under its 200°C maximum. For sustained full-load operation the TO-39 case should be thermally bonded to a small clip-on heatsink or to the equipment chassis through thermal compound.
The 2N4037 through-hole TO-39 outline requires three plated through-holes on 2.54 mm (0.1 inch) spacing, matched to the standard metal-can lead footprint. The case tab/flag orientation must match between the 2N4037 PNP and the 2N4036 NPN for shared PCB layouts in complementary stages. For SMD migration, modern equivalents such as MMBT3906 (SOT-23) or BCP51 (SOT-223) provide electrical substitution but require PCB rework - they are not drop-in TO-39 replacements.
Two common pitfalls with the 2N4037 are misreading the pinout and ignoring the Early voltage. Pin assignments for the TO-39 metal can vary between manufacturers of 2N-series parts; always verify against the specific vendor's datasheet before PCB layout. Second, with Vceo of 40V the device cannot be used directly across 48V telecom rails - in those applications consider a higher-Vceo part such as the BC161 (60V Vceo) or a modern MPSA92 (300V) in a different package.
合規資訊
The 2N4037 is available in both a RoHS-compliant lead-free finish (2N4037 PBFREE per DigiKey) and a traditional tin/lead finish (2N4037 TIN/LEAD per Mouser). AEC-Q100 automotive qualification is not pursued for this legacy 2N-series industrial part; for automotive designs migrate to AEC-Q100-qualified modern equivalents.
