2SD1691-Y-BP Equivalent & Substitute Parts

Part Overview

The 2SD1691-Y-BP is an NPN bipolar junction transistor manufactured by Micro Commercial Co, rated for 60 V collector-emitter breakdown voltage and 5 A maximum collector current in a TO-126 through-hole package. This device is classified as obsolete, making identification of active equivalent and substitute parts essential for ongoing production and maintenance applications. The 1.3 W power rating and specified saturation characteristics position this transistor for general-purpose switching and amplification circuits requiring moderate current handling at moderate voltage levels.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Current - Collector (Ic) Max	5	A
Voltage - Collector Emitter Breakdown (Max)	60	V
Vce Saturation (Max)	300 mV @ 200 mA, 2 A	—
Current - Collector Cutoff (Max)	10	µA (ICBO)
DC Current Gain (hFE) Min	160 @ 2 A, 1 V	—
Power - Max	1.3	W
Operating Temperature	−55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-225AA, TO-126-3	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the 2SD1691-Y-BP is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

Transistor type must be NPN
Collector-emitter breakdown voltage (VCEO) must equal or exceed 60 V
Maximum collector current (Ic) must equal or exceed 5 A
Vce saturation characteristics must be compatible with circuit requirements
DC current gain (hFE) must support intended biasing conditions
Collector cutoff current (ICBO) must not exceed specified limits

Mechanical Compatibility Criteria:

Through-hole mounting type required
Package must be TO-126 or TO-126-3 (pin-compatible)
Operating temperature range must encompass −55°C to 150°C

Compliance Requirements:

RoHS3 compliance required
ECCN and HTSUS classifications must align

Substitute parts are grouped into two categories: Direct Equivalents (matching all electrical and mechanical parameters) and Similar Alternatives (meeting core electrical requirements with minor parameter variations).

Parameter Comparison

Part Number	Manufacturer	Product Status	Ic (Max) A	VCEO (Max) V	Vce Sat (Max)	hFE (Min)	Power (Max) W	Package	Temp Range °C
2SD1691-Y-BP	Micro Commercial Co	Obsolete	5	60	300 mV @ 200 mA, 2 A	160 @ 2 A, 1 V	1.3	TO-126-3	−55 to 150
KSD1691YSTU	onsemi	Active	5	60	300 mV @ 200 mA, 2 A	160 @ 2 A, 1 V	1.3	TO-126-3	−55 to 150
KSD1691GS	onsemi	Active	5	60	300 mV @ 200 mA, 2 A	200 @ 2 A, 1 V	1.3	TO-126-3	−55 to 150
KSD1691YS	onsemi	Active	5	60	300 mV @ 200 mA, 2 A	160 @ 2 A, 1 V	1.3	TO-126-3	−55 to 150
BD439G	onsemi	Active	4	60	800 mV @ 300 mA, 3 A	40 @ 500 mA, 1 V	36	TO-126	−55 to 150
BD437G	onsemi	Active	4	45	800 mV @ 300 mA, 3 A	85 @ 500 mA, 1 V	36	TO-126	−55 to 150

Engineering Selection Recommendations

Direct Equivalent Selection:

KSD1691YSTU, KSD1691YS, and KSD1691GS are active-status NPN transistors manufactured by onsemi that meet or exceed all electrical and mechanical specifications of the 2SD1691-Y-BP. These parts maintain identical collector current (5 A), collector-emitter breakdown voltage (60 V), saturation voltage characteristics (300 mV @ 200 mA, 2 A), and power rating (1.3 W). All three are RoHS3 compliant and housed in TO-126-3 packages compatible with the original design.

KSD1691YSTU is supplied in tube packaging and represents the closest direct equivalent with matching DC current gain (160 @ 2 A, 1 V). KSD1691YS is supplied in bulk packaging and maintains identical electrical characteristics. KSD1691GS exhibits higher DC current gain (200 @ 2 A, 1 V) while maintaining all other specifications, suitable for applications where increased gain is beneficial.

Similar Alternative Selection:

BD439G and BD437G are active-status alternatives that satisfy the 60 V and 45 V collector-emitter breakdown requirements respectively, with TO-126 package compatibility. These devices differ in maximum collector current (4 A versus 5 A), saturation voltage (800 mV versus 300 mV), and power dissipation capability (36 W versus 1.3 W). Selection of these alternatives is appropriate only when circuit design accommodates the reduced current rating and higher saturation voltage.

All recommended substitutes maintain RoHS3 compliance and operating temperature ranges spanning −55°C to 150°C, ensuring regulatory and thermal compatibility with the original specification.

Frequently Asked Questions (FAQ)

Q: Can KSD1691YSTU directly replace 2SD1691-Y-BP in existing designs?

A: Yes. KSD1691YSTU is an active-status direct equivalent with identical electrical ratings (5 A, 60 V, 1.3 W) and saturation characteristics (300 mV @ 200 mA, 2 A). The TO-126-3 package is mechanically compatible with the original TO-126-3 footprint. No circuit modifications are required.

Q: What is the difference between KSD1691YSTU, KSD1691YS, and KSD1691GS?

A: All three are onsemi KSD1691 variants with identical voltage and current ratings. KSD1691YSTU is tube-packaged; KSD1691YS and KSD1691GS are bulk-packaged. KSD1691GS specifies minimum DC current gain of 200 @ 2 A, 1 V, compared to 160 for the other variants. This higher gain may improve circuit performance in applications sensitive to transistor gain variation.

Q: Can BD439G or BD437G be used as substitutes?

A: BD439G and BD437G are similar alternatives with compatible TO-126 packages and matching operating temperature ranges. However, they differ in critical parameters: maximum collector current is reduced to 4 A (versus 5 A), saturation voltage increases to 800 mV (versus 300 mV), and power rating increases to 36 W (versus 1.3 W). These alternatives are suitable only when circuit design accommodates the reduced current capability and higher saturation voltage.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. KSD1691YSTU, KSD1691YS, KSD1691GS, BD439G, and BD437G are all RoHS3 compliant, matching the compliance status of the original 2SD1691-Y-BP.

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

A: KSD1691YSTU, KSD1691YS, and KSD1691GS specify maximum junction temperature of 150°C. BD439G and BD437G specify operating temperature range of −55°C to 150°C. All alternatives support the original specification range of −55°C to 150°C.

Q: Why is the 2SD1691-Y-BP classified as obsolete?

A: The 2SD1691-Y-BP is no longer manufactured by Micro Commercial Co. Active equivalent parts from onsemi (KSD1691 series) provide identical functionality and are currently in production with established supply chains.

Q: What packaging options are available for direct equivalents?

A: KSD1691YSTU is supplied in tube packaging (35,885 pcs in stock). KSD1691YS is supplied in bulk packaging (1,520 pcs in stock). KSD1691GS is supplied in bulk packaging (5,950 pcs in stock). Selection depends on procurement and assembly requirements.

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