BC237BRL1G Equivalent & Substitute Parts

Part Overview

The BC237BRL1G is an NPN bipolar junction transistor manufactured by onsemi, rated for 45 V collector-emitter breakdown voltage and 100 mA maximum collector current. This device is packaged in TO-92 (TO-226-3) through-hole configuration and is classified as obsolete. The BC237BRL1G serves general-purpose small-signal amplification and switching applications in through-hole designs. Due to its obsolete status, equivalent and substitute parts are necessary for ongoing production, maintenance, and new design implementations.

Key Parameters

Parameter	BC237BRL1G
Transistor Type	NPN
Voltage - Collector Emitter Breakdown (Max)	45 V
Current - Collector (Ic) (Max)	100 mA
Power - Max	1 W
Frequency - Transition	200 MHz
DC Current Gain (hFE) (Min) @ Ic, Vce	200 @ 2mA, 5V
Vce Saturation (Max) @ Ib, Ic	600mV @ 5mA, 100mA
Current - Collector Cutoff (Max)	15nA
Operating Temperature	-55°C ~ 150°C (TJ)
Mounting Type	Through Hole
Package / Case	TO-226-3, TO-92-3 Long Body (Formed Leads)

Substitute Part Grouping Explanation

Substitution of the BC237BRL1G is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Transistor Type: NPN
Voltage - Collector Emitter Breakdown (Max): 45 V minimum
Current - Collector (Ic) (Max): 100 mA minimum
Vce Saturation (Max) @ Ib, Ic: 600mV @ 5mA, 100mA
Current - Collector Cutoff (Max): 15nA maximum
DC Current Gain (hFE) (Min) @ Ic, Vce: 200 minimum @ 2mA, 5V
Operating Temperature Range: -55°C ~ 150°C (TJ)

Direct Equivalents (Through-Hole TO-92 Package): Parts meeting all primary criteria with identical or superior electrical performance in the same through-hole package form factor are classified as direct equivalents. These include BC547BTA, BC547BTF, and BC547CTA.

Similar Substitutes (Through-Hole TO-92 Package): Parts meeting primary criteria with variations in secondary parameters (such as DC current gain range or power dissipation) are classified as similar substitutes. These include BC547ATA and BC547CTFR.

Package Variant (Surface Mount SOT-23): The BC847BLT1G meets all primary electrical criteria but uses surface-mount SOT-23-3 packaging instead of through-hole TO-92. This part is suitable only for designs that can accommodate surface-mount technology.

Higher Current Capability (Through-Hole E-Line): The ZTX450STZ exceeds primary current specifications (1 A vs. 100 mA) and maintains 45 V breakdown voltage. This part is suitable for applications requiring higher collector current capacity while maintaining through-hole compatibility.

Parameter Comparison

Parameter	BC237BRL1G	BC547BTA	BC547BTF	BC547ATA	BC547CTA	BC547CTFR	BC847BLT1G	ZTX450STZ
Transistor Type	NPN	NPN	NPN	NPN	NPN	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	45 V	45 V	45 V	45 V	45 V	45 V	45 V	45 V
Current - Collector (Ic) (Max)	100 mA	100 mA	100 mA	100 mA	100 mA	100 mA	100 mA	1 A
Power - Max	1 W	625 mW	500 mW	500 mW	500 mW	500 mW	300 mW	1 W
Frequency - Transition	200 MHz	300 MHz	300 MHz	300 MHz	300 MHz	300 MHz	100 MHz	150 MHz
DC Current Gain (hFE) (Min) @ Ic, Vce	200 @ 2mA, 5V	200 @ 2mA, 5V	200 @ 2mA, 5V	110 @ 2mA, 5V	420 @ 2mA, 5V	420 @ 2mA, 5V	200 @ 2mA, 5V	100 @ 150mA, 10V
Vce Saturation (Max) @ Ib, Ic	600mV @ 5mA, 100mA	600mV @ 5mA, 100mA	600mV @ 5mA, 100mA	600mV @ 5mA, 100mA	600mV @ 5mA, 100mA	600mV @ 5mA, 100mA	600mV @ 5mA, 100mA	250mV @ 15mA, 150mA
Current - Collector Cutoff (Max)	15nA	15nA	15nA	15nA	15nA	15nA	15nA	Not specified
Operating Temperature	-55°C ~ 150°C	-55°C ~ 150°C	150°C	150°C	150°C	150°C	-55°C ~ 150°C	Not specified
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Surface Mount	Through Hole
Package / Case	TO-92-3	TO-92-3	TO-92-3	TO-92-3	TO-92-3	TO-92-3	SOT-23-3	E-Line-3
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

For Direct Through-Hole Replacement (TO-92 Package):

BC547BTA, BC547BTF, BC547CTA, and BC547CTFR are active-status parts that meet or exceed all electrical specifications of the BC237BRL1G. These parts maintain identical voltage and current ratings, saturation characteristics, and cutoff current specifications. BC547BTA and BC547BTF are manufactured by Fairchild Semiconductor and onsemi respectively, both with ROHS3 compliance and REACH unaffected status. BC547CTA and BC547CTFR are onsemi products with identical compliance certifications. Selection among these four parts depends on packaging format availability (bulk, cut tape, or digi-reel) and current gain range requirements.

BC547ATA is functionally compatible but features a lower minimum DC current gain (110 vs. 200), making it suitable only for applications where lower gain is acceptable or where gain variation is not critical.

For Surface-Mount Applications:

BC847BLT1G provides electrical equivalence in surface-mount SOT-23-3 packaging. This part is suitable only for PCB designs that accommodate surface-mount technology. The reduced power rating (300 mW vs. 1 W) and lower transition frequency (100 MHz vs. 200 MHz) must be evaluated against application requirements.

For Higher Current Applications:

ZTX450STZ supports 1 A collector current while maintaining 45 V breakdown voltage and 1 W power dissipation. This part is suitable for applications requiring higher current capacity than the 100 mA specification of the BC237BRL1G. The E-Line package is through-hole compatible. Lower saturation voltage (250 mV vs. 600 mV) and lower minimum gain (100 vs. 200) represent design trade-offs.

All recommended substitutes carry active product status and current compliance certifications (ROHS3, REACH unaffected, EAR99).

Frequently Asked Questions (FAQ)

Q: Can BC547BTA directly replace BC237BRL1G in existing designs?

A: Yes. BC547BTA meets all primary electrical specifications: 45 V breakdown voltage, 100 mA maximum collector current, 600 mV saturation voltage at specified conditions, 200 minimum DC current gain, and 15 nA maximum cutoff current. Both use TO-92-3 through-hole packaging. The higher transition frequency (300 MHz vs. 200 MHz) and lower power rating (625 mW vs. 1 W) are secondary parameters that do not prevent substitution in most applications.

Q: What is the difference between BC547BTA, BC547BTF, BC547CTA, and BC547CTFR?

A: All four parts meet identical electrical specifications. Differences are in manufacturer (Fairchild Semiconductor vs. onsemi), packaging format (bulk vs. cut tape), and DC current gain range. BC547BTA and BC547ATA are Fairchild products in bulk packaging. BC547BTF, BC547CTA, and BC547CTFR are onsemi products in cut tape format. BC547CTA and BC547CTFR feature higher minimum DC current gain (420 vs. 200). Selection depends on packaging availability and gain requirements.

Q: Can BC847BLT1G replace BC237BRL1G?

A: BC847BLT1G is electrically equivalent but uses surface-mount SOT-23-3 packaging instead of through-hole TO-92. Substitution is possible only in designs that accommodate surface-mount components. The reduced power rating (300 mW vs. 1 W) and lower transition frequency (100 MHz vs. 200 MHz) must be evaluated for the specific application.

Q: When should ZTX450STZ be used instead of BC237BRL1G?

A: ZTX450STZ is suitable when collector current exceeds 100 mA, up to 1 A maximum. It maintains 45 V breakdown voltage and 1 W power dissipation. The E-Line package is through-hole compatible. Lower saturation voltage (250 mV vs. 600 mV) and lower minimum DC current gain (100 vs. 200) represent design trade-offs that must be evaluated for the specific application.

Q: Are all substitute parts RoHS compliant?

A: BC547BTA, BC547BTF, BC547CTA, BC547CTFR, BC847BLT1G, and ZTX450STZ all carry ROHS3 compliance certification. All parts are REACH unaffected and classified as EAR99 for export control purposes.

Q: What is the operating temperature range for substitute parts?

A: BC237BRL1G, BC547BTA, and BC847BLT1G specify -55°C to 150°C (TJ). BC547BTF, BC547ATA, BC547CTA, and BC547CTFR specify 150°C maximum (TJ) without lower limit specification. ZTX450STZ does not specify operating temperature range in provided data. Applications requiring full -55°C to 150°C range should use BC237BRL1G, BC547BTA, or BC847BLT1G.

Q: What is the difference in DC current gain between BC547ATA and BC547CTA?

A: BC547ATA specifies minimum DC current gain of 110 @ 2mA, 5V. BC547CTA specifies minimum DC current gain of 420 @ 2mA, 5V. Both meet the BC237BRL1G minimum requirement of 200. BC547CTA provides higher gain margin and is suitable for applications sensitive to gain variation.

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