BC559 Equivalent & Substitute Parts

Part Overview

The BC559 is a PNP bipolar junction transistor (BJT) manufactured by onsemi, designed for general-purpose switching and amplification applications. The device operates at a maximum collector current of 100 mA with a collector-emitter breakdown voltage of 30 V and maximum power dissipation of 500 mW. The BC559 is packaged in a TO-92-3 through-hole configuration suitable for conventional PCB assembly.

The BC559 carries an obsolete product status. Locating equivalent substitute parts is necessary to support ongoing production requirements, field repairs, and design continuity where this component remains specified in active applications.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	100	mA
Voltage - Collector Emitter Breakdown (Max)	30	V
Vce Saturation (Max) @ Ib, Ic	650 mV @ 5 mA, 100 mA	—
Current - Collector Cutoff (Max)	15	nA
Power - Max	500	mW
Frequency - Transition	150	MHz
Operating Temperature (TJ)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-92-3 (TO-226AA)	—

Substitute Part Grouping Explanation

Substitution of the BC559 is determined by electrical and mechanical parameter equivalence. The following criteria establish valid substitute relationships:

Electrical Parameters (Must Match):

Transistor Type: PNP
Current - Collector (Ic) (Max): 100 mA
Voltage - Collector Emitter Breakdown (Max): 30 V
Vce Saturation (Max) @ Ib, Ic: 650 mV @ 5 mA, 100 mA
Current - Collector Cutoff (Max): 15 nA
Power - Max: 500 mW
Frequency - Transition: 150 MHz
Operating Temperature (TJ): 150 °C

Mechanical Parameters (Must Match):

Mounting Type: Through Hole
Package / Case: TO-92-3 (TO-226AA)

The BC559BTA meets all specified electrical and mechanical parameters and is therefore a valid substitute for the BC559.

Parameter Comparison

Parameter	BC559	BC559BTA	Match
Transistor Type	PNP	PNP	✓
Current - Collector (Ic) (Max)	100 mA	100 mA	✓
Voltage - Collector Emitter Breakdown (Max)	30 V	30 V	✓
Vce Saturation (Max) @ Ib, Ic	650 mV @ 5 mA, 100 mA	650 mV @ 5 mA, 100 mA	✓
Current - Collector Cutoff (Max)	15 nA	15 nA	✓
DC Current Gain (hFE) (Min) @ Ic, Vce	110 @ 2 mA, 5 V	200 @ 2 mA, 5 V	Exceeds
Power - Max	500 mW	500 mW	✓
Frequency - Transition	150 MHz	150 MHz	✓
Operating Temperature (TJ)	150 °C	150 °C	✓
Mounting Type	Through Hole	Through Hole	✓
Package / Case	TO-92-3 (TO-226AA)	TO-92-3 (TO-226AA)	✓
Product Status	Obsolete	Active	—

Engineering Selection Recommendations

The BC559BTA is a direct electrical and mechanical equivalent to the BC559. The BC559BTA carries an active product status, ensuring ongoing availability and supply chain continuity. The BC559BTA is RoHS3 compliant, meeting current environmental and regulatory requirements for new designs and production.

The DC Current Gain (hFE) of the BC559BTA (200 @ 2 mA, 5 V) exceeds the minimum specification of the BC559 (110 @ 2 mA, 5 V). This higher gain does not violate the BC559 specification and remains within acceptable operating parameters for circuits designed around the BC559.

Both parts share identical electrical ratings and the same TO-92-3 through-hole package, enabling direct pin-compatible substitution without circuit modification or PCB redesign.

Frequently Asked Questions (FAQ)

Q: Can the BC559BTA be used as a direct replacement for the BC559 in existing designs?

A: Yes. The BC559BTA is electrically and mechanically equivalent to the BC559. All critical parameters—collector current, breakdown voltage, saturation voltage, power dissipation, transition frequency, and operating temperature—are identical. The TO-92-3 package pinout is identical, enabling direct substitution without circuit changes.

Q: What is the difference between the BC559 and BC559BTA?

A: The primary differences are product status and packaging format. The BC559 is obsolete; the BC559BTA is active. The BC559BTA is supplied in cut tape (CT) packaging and is RoHS3 compliant. The BC559BTA exhibits a higher DC current gain (200 versus 110 minimum), which is a performance advantage and does not affect compatibility.

Q: Are there any compliance or certification differences?

A: The BC559BTA is RoHS3 compliant and carries REACH Unaffected status, meeting current environmental regulations. The BC559 carries REACH Unaffected status. Both parts are classified as EAR99 for export control purposes.

Q: Does the higher DC current gain of the BC559BTA affect circuit operation?

A: No. The BC559BTA's higher DC current gain (200 @ 2 mA, 5 V) exceeds the BC559 minimum specification (110 @ 2 mA, 5 V) and remains within acceptable operating parameters. Circuits designed for the BC559 will operate correctly with the BC559BTA.

Q: What is the moisture sensitivity level (MSL) of the BC559BTA?

A: The BC559BTA carries a moisture sensitivity level designation of Not Applicable, indicating no moisture sensitivity requirements for storage or handling.

Q: Can the BC559BTA be used in new designs?

A: Yes. The BC559BTA is an active product with current manufacturing support and is suitable for new designs requiring a PNP BJT with 100 mA collector current, 30 V breakdown voltage, and TO-92-3 through-hole packaging.

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