ZTX751STZ Equivalent & Substitute Parts

Part Overview

The ZTX751STZ is a PNP bipolar junction transistor manufactured by Diodes Incorporated, designed for general-purpose switching and amplification applications. This device operates at maximum collector current of 2 A with a 60 V collector-emitter breakdown voltage rating. The ZTX751STZ is classified as Active product status with 1421 pieces currently in stock. Substitute parts are necessary when primary inventory becomes unavailable, when sourcing from alternative manufacturers is required for supply chain optimization, or when design flexibility permits operation within relaxed electrical parameter ranges.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) Max	2	A
Voltage - Collector Emitter Breakdown (Max)	60	V
Vce Saturation (Max) @ Ib, Ic	500 mV @ 200 mA, 2 A	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) Min @ Ic, Vce	100 @ 500 mA, 2 V	—
Power - Max	1	W
Frequency - Transition	100	MHz
Operating Temperature	−55 to 200	°C
Mounting Type	Through Hole	—
Package / Case	E-Line-3, Formed Leads (TO-92 compatible)	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution eligibility for the ZTX751STZ is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor type must be PNP
Collector-emitter breakdown voltage must be 60 V or greater
Collector current rating must be 2 A or greater
Mounting type must be Through Hole
Package must be TO-92-3 or E-Line-3 compatible form factor
Collector cutoff current must not exceed 100 nA

Secondary Compatibility Parameters:

Vce saturation characteristics at specified bias conditions
DC current gain (hFE) minimum values
Operating temperature range
RoHS3 compliance status

Substitute parts are grouped into two categories based on current rating alignment:

Group A (Full Current Rating Match): Parts rated for 2 A collector current with electrical characteristics matching or exceeding the ZTX751STZ specification.

Group B (Reduced Current Rating): Parts rated for 700 mA collector current. These substitutes are electrically compatible but operate within a reduced current envelope and are suitable only for applications where maximum collector current does not exceed 700 mA.

Parameter Comparison

Parameter	ZTX751STZ (Diodes)	MPS751 (Fairchild)	MPS751-D26Z (onsemi)	KSA708YTA (onsemi)	KSA708CYTA (onsemi)
Transistor Type	PNP	PNP	PNP	PNP	PNP
Current - Collector (Ic) Max	2 A	2 A	2 A	700 mA	700 mA
Voltage - Collector Emitter Breakdown (Max)	60 V	60 V	60 V	60 V	60 V
Vce Saturation (Max) @ Ib, Ic	500 mV @ 200 mA, 2 A	500 mV @ 200 mA, 2 A	500 mV @ 200 mA, 2 A	700 mV @ 50 mA, 500 mA	700 mV @ 50 mA, 500 mA
Current - Collector Cutoff (Max)	100 nA	100 nA	100 nA	100 nA	100 nA
DC Current Gain (hFE) Min @ Ic, Vce	100 @ 500 mA, 2 V	75 @ 1 A, 2 V	40 @ 2 A, 2 V	120 @ 50 mA, 2 V	120 @ 500 mA, 2 V
Power - Max	1 W	625 mW	625 mW	800 mW	800 mW
Frequency - Transition	100 MHz	75 MHz	75 MHz	50 MHz	50 MHz
Operating Temperature	−55 to 200 °C	−55 to 150 °C	−55 to 150 °C	−55 to 150 °C	−55 to 150 °C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	E-Line-3, TO-92 compatible	TO-226-3, TO-92-3	TO-226-3, TO-92-3	TO-226-3, TO-92-3	TO-226-3, TO-92-3
RoHS Status	ROHS3 Compliant	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active	Active	Last Time Buy

Engineering Selection Recommendations

MPS751 and MPS751-D26Z (Full Current Rating Substitutes)

The MPS751 (Fairchild Semiconductor) and MPS751-D26Z (onsemi) are direct electrical substitutes for the ZTX751STZ, both rated for 2 A collector current and 60 V breakdown voltage. Both parts maintain the same Vce saturation specification at 2 A operation. The MPS751-D26Z is manufactured by onsemi and carries ROHS3 compliance certification, matching the environmental compliance profile of the primary part. The MPS751-D26Z is currently in Active product status with 35200 pieces in stock, providing superior supply availability. The Fairchild MPS751 remains in Active status with 1300 pieces available. Both parts are suitable for direct substitution in applications requiring full 2 A collector current capability.

KSA708YTA (Reduced Current Rating Substitute)

The KSA708YTA manufactured by onsemi is rated for 700 mA maximum collector current, representing a 65% reduction from the ZTX751STZ 2 A rating. This part is suitable for substitution only in applications where the actual operating collector current does not exceed 700 mA. The KSA708YTA carries ROHS3 compliance and is in Active product status with 35200 pieces in stock. The transition frequency is 50 MHz compared to 100 MHz for the primary part, and maximum power dissipation is 800 mW versus 1 W.

KSA708CYTA (Reduced Current Rating, Limited Availability)

The KSA708CYTA manufactured by onsemi is electrically identical to the KSA708YTA but carries Last Time Buy product status, indicating discontinued manufacturing. This part is rated for 700 mA collector current and is suitable only for applications within the reduced current envelope. With 5953 pieces in stock, this part should be considered only when KSA708YTA availability is exhausted and design flexibility permits the reduced current rating.

Recommendation Summary

For applications requiring 2 A collector current capability, select MPS751-D26Z as the primary substitute due to Active product status, ROHS3 compliance, and superior inventory availability. For applications operating at 700 mA or below, KSA708YTA provides an alternative source with equivalent electrical performance within its current rating.

Frequently Asked Questions (FAQ)

Q: Can KSA708YTA or KSA708CYTA be used in place of ZTX751STZ in all applications?

A: No. The KSA708 series is rated for maximum 700 mA collector current, while the ZTX751STZ is rated for 2 A. Substitution is valid only when the application circuit operates at collector currents not exceeding 700 mA. Exceeding this current rating will result in device failure.

Q: What is the difference between MPS751 and MPS751-D26Z?

A: Both parts are rated for 2 A collector current and 60 V breakdown voltage with identical Vce saturation characteristics. The primary difference is manufacturer: MPS751 is manufactured by Fairchild Semiconductor, while MPS751-D26Z is manufactured by onsemi. The MPS751-D26Z carries explicit ROHS3 compliance certification. Both are electrically interchangeable.

Q: Are the TO-92-3 and E-Line-3 packages physically compatible?

A: Yes. The ZTX751STZ is specified as E-Line-3 with TO-92 compatible form factor. The substitute parts specified as TO-92-3 or TO-226-3 are mechanically compatible with TO-92 footprints and can be used as direct physical replacements in through-hole applications.

Q: Why does the ZTX751STZ have a higher operating temperature maximum (200°C) compared to substitute parts (150°C)?

A: The ZTX751STZ is specified with a maximum junction temperature of 200°C, while the substitute parts are specified at 150°C maximum. This represents a difference in device design and thermal rating. For applications operating near the upper temperature limit, the ZTX751STZ provides extended thermal headroom.

Q: What is the significance of the DC Current Gain (hFE) differences between parts?

A: DC current gain varies across the substitute parts. The ZTX751STZ specifies minimum hFE of 100 at 500 mA. The MPS751-D26Z specifies minimum hFE of 40 at 2 A, while KSA708YTA specifies minimum hFE of 120 at 50 mA. These differences affect base drive requirements in switching circuits. Applications with tight base current budgets should verify hFE specifications against circuit design requirements.

Q: Is KSA708CYTA recommended for new designs?

A: No. The KSA708CYTA carries Last Time Buy product status, indicating that manufacturing has been discontinued and inventory will be depleted. New designs should specify KSA708YTA (Active status) or MPS751-D26Z (Active status) to ensure long-term supply availability.

Q: What is the maximum power dissipation difference between the main part and substitutes?

A: The ZTX751STZ is rated for 1 W maximum power dissipation. The MPS751 and MPS751-D26Z are rated for 625 mW, while KSA708YTA and KSA708CYTA are rated for 800 mW. Applications requiring sustained power dissipation above 625 mW should verify that the selected substitute part can accommodate the thermal load.

Q: Are all substitute parts RoHS3 compliant?

A: MPS751-D26Z, KSA708YTA, and KSA708CYTA are explicitly specified as ROHS3 compliant. The Fairchild MPS751 does not have RoHS status specified in the provided data. For applications requiring RoHS3 compliance certification, select MPS751-D26Z, KSA708YTA, or KSA708CYTA.

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