CPH3121-TL-E Equivalent & Substitute Parts

Part Overview

The CPH3121-TL-E is a Bipolar (BJT) Transistor manufactured by onsemi, classified as a PNP surface mount device rated for 12 V collector-emitter breakdown voltage and 3 A maximum collector current. This component is packaged in the 3-CPH (SC-96) configuration and operates at a maximum junction temperature of 150°C with 900 mW power dissipation capability. The CPH3121-TL-E is designated as obsolete product status. Identification of equivalent and substitute parts is necessary to support ongoing design requirements, legacy system maintenance, and supply chain continuity when original inventory becomes unavailable.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	3	A
Voltage - Collector Emitter Breakdown (Max)	12	V
Vce Saturation (Max) @ Ib, Ic	165 mV @ 30 mA, 1.5 A	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	200 @ 500 mA, 2 V	—
Power - Max	900	mW
Frequency - Transition	380	MHz
Operating Temperature (TJ)	150	°C
Mounting Type	Surface Mount	—
Package / Case	SC-96	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the CPH3121-TL-E is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor Type: PNP (mandatory match)
Voltage - Collector Emitter Breakdown (Max): ≥ 12 V
Current - Collector (Ic) (Max): ≥ 3 A
Mounting Type: Surface Mount
RoHS Status: ROHS3 Compliant

Secondary Compatibility Parameters:

Power - Max: ≥ 900 mW
DC Current Gain (hFE) (Min): ≥ 200 @ 500 mA, 2 V
Current - Collector Cutoff (Max): ≤ 100 nA
Operating Temperature (TJ): ≥ 150°C

Substitute parts are classified into two categories:

Direct Substitutes (Identical Electrical Performance): Parts meeting all primary and secondary criteria with equivalent or superior specifications across all measured parameters.

Similar Substitutes (Functional Equivalents with Trade-offs): Parts meeting primary electrical criteria but with variations in secondary parameters such as frequency response, power dissipation, or package configuration. These parts are suitable for applications where the specific trade-off does not impact system performance.

Parameter Comparison

Parameter	CPH3121-TL-E	CPH3106-TL-E	NSS12200LT1G	2SB1705TL	FMMT717TA	ZXTP25015DFHTA
Manufacturer	onsemi	onsemi	onsemi	Rohm Semiconductor	Diodes Incorporated	Diodes Incorporated
Transistor Type	PNP	PNP	PNP	PNP	PNP	PNP
Current - Collector (Ic) (Max)	3 A	3 A	2 A	3 A	2.5 A	4 A
Voltage - Collector Emitter Breakdown (Max)	12 V	12 V	12 V	12 V	12 V	15 V
Vce Saturation (Max) @ Ib, Ic	165 mV @ 30 mA, 1.5 A	165 mV @ 30 mA, 1.5 A	180 mV @ 200 mA, 2 A	250 mV @ 30 mA, 1.5 A	220 mV @ 50 mA, 2.5 A	220 mV @ 500 mA, 5 A
Current - Collector Cutoff (Max)	100 nA	100 nA	100 nA	100 nA	100 nA	50 nA
DC Current Gain (hFE) (Min) @ Ic, Vce	200 @ 500 mA, 2 V	200 @ 500 mA, 2 V	250 @ 500 mA, 2 V	270 @ 500 mA, 2 V	300 @ 100 mA, 2 V	300 @ 10 mA, 2 V
Power - Max	900 mW	900 mW	460 mW	500 mW	625 mW	1.25 W
Frequency - Transition	380 MHz	280 MHz	100 MHz	280 MHz	110 MHz	295 MHz
Operating Temperature (TJ)	150°C	150°C	-55°C ~ 150°C	150°C	-55°C ~ 150°C	-55°C ~ 150°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	SC-96	SC-96	TO-236-3, SC-59, SOT-23-3	SC-96	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3
Product Status	Obsolete	Obsolete	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

CPH3106-TL-E (onsemi): This part is a direct electrical equivalent to the CPH3121-TL-E with identical maximum collector current (3 A), collector-emitter breakdown voltage (12 V), saturation voltage, and power dissipation (900 mW). The primary difference is reduced transition frequency (280 MHz versus 380 MHz). Both parts are obsolete and ROHS3 compliant. Selection of CPH3106-TL-E is appropriate for applications where the lower frequency specification does not impact circuit performance requirements.

2SB1705TL (Rohm Semiconductor): This part meets the primary substitution criteria with 3 A maximum collector current and 12 V breakdown voltage. It is an active product with ROHS3 compliance and MSL 1 rating. The 2SB1705TL exhibits higher saturation voltage (250 mV versus 165 mV) and lower power dissipation (500 mW versus 900 mW). Selection is suitable for applications where the saturation voltage specification is acceptable and thermal dissipation requirements are reduced.

ZXTP25015DFHTA (Diodes Incorporated): This part exceeds the primary electrical criteria with 4 A maximum collector current and 15 V breakdown voltage. It is an active product with ROHS3 compliance and superior power dissipation (1.25 W). The ZXTP25015DFHTA operates across an extended temperature range (-55°C to 150°C) and features a different package configuration (SOT-23-3 versus SC-96). Selection is appropriate for applications requiring higher current capacity, voltage margin, or thermal performance, provided PCB layout accommodates the SOT-23-3 package.

NSS12200LT1G (onsemi): This part meets the 12 V breakdown voltage requirement but is limited to 2 A maximum collector current, below the 3 A specification of the CPH3121-TL-E. It is an active product with ROHS3 compliance and extended temperature range (-55°C to 150°C). Selection is suitable only for applications where the reduced current capacity does not exceed design requirements.

FMMT717TA (Diodes Incorporated): This part is limited to 2.5 A maximum collector current, below the 3 A specification of the CPH3121-TL-E. It is an active product with ROHS3 compliance and extended temperature range (-55°C to 150°C). Selection is suitable only for applications where the reduced current capacity does not exceed design requirements.

Frequently Asked Questions (FAQ)

Q: Can the CPH3121-TL-E be directly replaced with the CPH3106-TL-E?

A: Yes. Both parts are manufactured by onsemi and share identical electrical specifications for maximum collector current (3 A), collector-emitter breakdown voltage (12 V), saturation voltage (165 mV @ 30 mA, 1.5 A), and power dissipation (900 mW). The CPH3106-TL-E operates at 280 MHz transition frequency compared to 380 MHz for the CPH3121-TL-E. Direct substitution is valid when the lower frequency specification does not impact circuit performance.

Q: What is the primary limitation of NSS12200LT1G and FMMT717TA as substitutes?

A: Both NSS12200LT1G and FMMT717TA are limited to maximum collector currents below the CPH3121-TL-E specification: NSS12200LT1G at 2 A and FMMT717TA at 2.5 A, compared to 3 A for the CPH3121-TL-E. These parts are suitable only for applications where the design current requirement does not exceed their maximum ratings.

Q: Why does ZXTP25015DFHTA have a different package than the CPH3121-TL-E?

A: The ZXTP25015DFHTA is packaged in SOT-23-3 (TO-236-3, SC-59) configuration, while the CPH3121-TL-E uses SC-96 packaging. Both are surface mount packages, but they have different physical dimensions and pin layouts. PCB redesign is required to accommodate the ZXTP25015DFHTA package. This part is selected when higher current capacity (4 A), voltage margin (15 V), or thermal performance (1.25 W) is required.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed—CPH3106-TL-E, NSS12200LT1G, 2SB1705TL, FMMT717TA, and ZXTP25015DFHTA—are ROHS3 compliant and carry MSL 1 (Unlimited) moisture sensitivity rating, matching the compliance profile of the CPH3121-TL-E.

Q: What is the significance of the 2SB1705TL saturation voltage specification?

A: The 2SB1705TL exhibits a saturation voltage of 250 mV @ 30 mA, 1.5 A, compared to 165 mV for the CPH3121-TL-E. This 85 mV difference results in higher voltage drop across the transistor during saturation. In applications where saturation voltage directly impacts circuit performance (such as low-voltage switching or precision current sources), this specification difference must be evaluated against design tolerances.

Q: Can the CPH3121-TL-E be substituted with parts having higher voltage ratings?

A: Yes. Parts with higher collector-emitter breakdown voltage ratings (such as ZXTP25015DFHTA at 15 V) can be substituted in applications designed for 12 V operation. The higher voltage rating provides additional safety margin and does not degrade performance in circuits operating below the rated voltage. However, other electrical parameters such as current capacity, saturation voltage, and power dissipation must still meet or exceed design requirements.

Q: What is the impact of transition frequency differences on substitution?

A: Transition frequency (fT) determines the maximum frequency at which the transistor maintains useful gain. The CPH3121-TL-E operates at 380 MHz, while CPH3106-TL-E operates at 280 MHz. For applications operating below 280 MHz, the frequency difference is not significant. For high-frequency switching applications approaching or exceeding 280 MHz, the reduced frequency of CPH3106-TL-E may impact circuit performance. NSS12200LT1G and FMMT717TA, with transition frequencies of 100 MHz and 110 MHz respectively, are suitable only for low-frequency applications.

Q: Are extended temperature range specifications important for substitution?

A: Extended temperature range specifications (-55°C to 150°C) provided by NSS12200LT1G, FMMT717TA, and ZXTP25015DFHTA offer broader operational capability compared to the CPH3121-TL-E (150°C maximum). For applications operating only at or near room temperature with maximum junction temperatures below 150°C, the extended range provides no functional advantage. For applications requiring operation at temperatures below 0°C or with thermal cycling, parts with extended temperature specifications are preferred.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message