BC237BRL1 Equivalent & Substitute Parts

Part Overview

The BC237BRL1 is an NPN bipolar junction transistor manufactured by onsemi, designed for small-signal switching and amplification applications. This device features a 45 V collector-emitter breakdown voltage rating and supports collector currents up to 100 mA with a maximum power dissipation of 350 mW in a Through Hole TO-92 package.

The BC237BRL1 is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this transistor.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Collector Current (Max)	100	mA
Collector-Emitter Breakdown Voltage (Max)	45	V
Vce Saturation (Max)	600	mV @ 5mA, 100mA
Collector Cutoff Current (Max)	15	nA
DC Current Gain (hFE Min)	200	@ 2mA, 5V
Power Dissipation (Max)	350	mW
Transition Frequency	200	MHz
Operating Temperature Range	-55 to 150	°C
Mounting Type	Through Hole	—
Package	TO-92-3	—

Substitute Part Grouping Explanation

Substitution of the BC237BRL1 is determined by electrical and mechanical parameter compatibility within the NPN bipolar transistor category. The critical parameters governing substitution are:

Electrical Compatibility Requirements:

Transistor type must be NPN
Collector-emitter breakdown voltage must be ≥45 V
Maximum collector current must be ≥100 mA
DC current gain (hFE) must be ≥200 @ 2mA, 5V
Vce saturation must be ≤600 mV @ 5mA, 100mA
Collector cutoff current must be ≤15 nA
Operating temperature range must encompass -55°C to 150°C

Mechanical Compatibility Requirements:

Mounting type must be Through Hole
Package must be TO-92-3 or TO-92-compatible form factor

The substitute parts BC547BTA, BC547BTF, and ZTX450STZ meet these criteria with equal or superior electrical performance characteristics. All three devices maintain the same collector-emitter breakdown voltage, collector current rating, and saturation voltage specifications as the BC237BRL1, ensuring functional equivalence in circuit applications.

Parameter Comparison

Parameter	BC237BRL1	BC547BTA	BC547BTF	ZTX450STZ
Manufacturer	onsemi	Fairchild Semiconductor	onsemi	Diodes Incorporated
Product Status	Obsolete	Active	Active	Active
Transistor Type	NPN	NPN	NPN	NPN
Ic (Max)	100 mA	100 mA	100 mA	1 A
Vce Breakdown (Max)	45 V	45 V	45 V	45 V
Vce Saturation (Max)	600 mV @ 5mA, 100mA	600 mV @ 5mA, 100mA	600 mV @ 5mA, 100mA	250 mV @ 15mA, 150mA
Icbo (Max)	15 nA	15 nA	15 nA	—
hFE (Min)	200 @ 2mA, 5V	200 @ 2mA, 5V	200 @ 2mA, 5V	100 @ 150mA, 10V
Power (Max)	350 mW	625 mW	500 mW	1 W
Frequency - Transition	200 MHz	300 MHz	300 MHz	150 MHz
Operating Temperature	-55 to 150°C	-55 to 150°C	-55 to 150°C	—
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package	TO-92-3	TO-92-3	TO-92-3	E-Line (TO-92 compatible)
RoHS Status	Non-compliant	—	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

BC547BTA (Fairchild Semiconductor)

The BC547BTA is a direct functional equivalent to the BC237BRL1. It maintains identical electrical specifications for collector current, breakdown voltage, saturation voltage, and DC current gain. The BC547BTA offers superior power dissipation capability (625 mW versus 350 mW) and higher transition frequency (300 MHz versus 200 MHz), providing enhanced performance margins. This device is in active production status, ensuring long-term supply availability. The BC547BTA is suitable for applications requiring direct pin-compatible replacement with improved thermal and frequency performance.

BC547BTF (onsemi)

The BC547BTF is supplied by the same manufacturer as the BC237BRL1 and provides identical electrical performance specifications. It maintains the same collector current, breakdown voltage, saturation voltage, and DC current gain parameters. The BC547BTF offers increased power dissipation (500 mW versus 350 mW) and higher transition frequency (300 MHz versus 200 MHz). This device is in active production status and is RoHS3 compliant, meeting modern environmental and regulatory requirements. The BC547BTF is the preferred substitute when maintaining the same manufacturer source is a design requirement.

ZTX450STZ (Diodes Incorporated)

The ZTX450STZ is a higher-performance substitute suitable for applications requiring increased current handling capability. This device supports collector currents up to 1 A (ten times the BC237BRL1 rating) and provides superior power dissipation (1 W versus 350 mW). The ZTX450STZ maintains the same 45 V breakdown voltage specification and offers lower saturation voltage (250 mV versus 600 mV), resulting in reduced power loss during saturation. This device is in active production status and is RoHS3 compliant. The ZTX450STZ is appropriate for applications where higher current capacity or improved thermal performance is beneficial, provided the E-Line package form factor is mechanically compatible with the circuit board layout.

Frequently Asked Questions (FAQ)

Q: Can the BC237BRL1 be directly replaced with BC547BTA, BC547BTF, or ZTX450STZ without circuit modification?

A: Yes, all three substitute parts maintain the same collector-emitter breakdown voltage (45 V), maximum collector current (100 mA minimum), saturation voltage (600 mV maximum), and DC current gain (200 minimum) specifications as the BC237BRL1. All devices are NPN transistors in Through Hole packages with identical pin configurations. Direct substitution is electrically compatible without circuit redesign.

Q: What is the difference between BC547BTA and BC547BTF?

A: Both devices are BC547 variants with identical electrical specifications. The primary differences are manufacturer (Fairchild Semiconductor for BC547BTA versus onsemi for BC547BTF) and packaging format (Bulk for BC547BTA versus Cut Tape for BC547BTF). BC547BTF is RoHS3 compliant, while BC547BTA compliance status is not specified in the provided data.

Q: When should ZTX450STZ be selected instead of BC547BTA or BC547BTF?

A: The ZTX450STZ should be selected when the application requires higher collector current capacity (up to 1 A versus 100 mA) or when lower saturation voltage (250 mV versus 600 mV) is beneficial for reducing power dissipation during saturation operation. The ZTX450STZ is also suitable when maximum power dissipation capability (1 W versus 350-625 mW) is a design requirement.

Q: Are there package compatibility considerations between these substitute parts?

A: BC237BRL1, BC547BTA, and BC547BTF all use standard TO-92-3 packages with identical pin configurations and mechanical dimensions. The ZTX450STZ uses an E-Line package, which is mechanically compatible with TO-92 form factors but may have slightly different lead spacing. Verify mechanical fit with the circuit board layout before final component selection.

Q: What is the significance of the obsolete status of BC237BRL1?

A: Obsolete status indicates that the BC237BRL1 is no longer in active production. Existing inventory may be limited, and long-term supply cannot be guaranteed. The substitute parts (BC547BTA, BC547BTF, and ZTX450STZ) are all in active production status, ensuring reliable availability for current and future production requirements.

Q: Do the substitute parts meet modern regulatory compliance requirements?

A: BC547BTF and ZTX450STZ are both RoHS3 compliant, meeting current environmental and regulatory standards. BC547BTA compliance status is not specified in the provided data. For applications requiring RoHS compliance certification, BC547BTF or ZTX450STZ are the appropriate selections.

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