4N49 Optoisolator Transistor with Base Output - Equivalent & Substitute Parts

Part Overview

The 4N49 is a 1000VDC optoisolator with transistor output and base connection, housed in a TO-78-6 metal can package. This component provides galvanic isolation for DC input signals with a single-channel transistor output stage. The part is currently active in production with 2200 units in stock. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are maintained across the specified parameter set.

Key Parameters

Parameter	Value
Isolation Voltage	1000VDC
Number of Channels	1
Current Transfer Ratio (Min)	200% @ 1mA
Current Transfer Ratio (Max)	1000% @ 1mA
Output Type	Transistor with Base
Voltage - Output (Max)	40V
Current - Output / Channel	50mA
Vce Saturation (Max)	300mV
Voltage - Forward (Vf) (Typ)	1.5V (Max)
Current - DC Forward (If) (Max)	40mA
Operating Temperature Range	-55°C ~ 125°C
Package / Case	TO-78-6 Metal Can
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the 4N49 are qualified based on the following criteria:

Isolation voltage of 1000VDC or greater
Single-channel configuration
Current transfer ratio range: 200% (Min) to 1000% (Max) @ 1mA
Transistor output with base connection
Maximum output voltage of 40V
Maximum output current of 50mA per channel
Vce saturation maximum of 300mV
Operating temperature range of -55°C to 125°C or wider
TO-78-6 metal can package with through-hole mounting
Input type: DC

Parts meeting all these electrical and mechanical parameters are considered parametric equivalents and direct substitutes for the 4N49.

Parameter Comparison

Parameter	4N49	JANTX4N49A	4N49TX
Manufacturer	TT Electronics/Optek Technology	TT Electronics/Optek Technology	TT Electronics/Optek Technology
Isolation Voltage	1000VDC	1000VDC	1000VDC
Number of Channels	1	1	1
Current Transfer Ratio (Min)	200% @ 1mA	200% @ 1mA	200% @ 1mA
Current Transfer Ratio (Max)	1000% @ 1mA	1000% @ 1mA	1000% @ 1mA
Rise / Fall Time (Typ)	25µs, 25µs	20µs, 20µs (Max)	25µs, 25µs
Output Type	Transistor with Base	Transistor with Base	Transistor with Base
Voltage - Output (Max)	40V	40V	40V
Current - Output / Channel	50mA	50mA	50mA
Vce Saturation (Max)	300mV	300mV	300mV
Voltage - Forward (Vf) (Typ)	1.5V (Max)	1.5V (Max)	1.5V (Max)
Current - DC Forward (If) (Max)	40mA	40mA	40mA
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C
Package / Case	TO-78-6 Metal Can	TO-78-6 Metal Can	TO-78-6 Metal Can
Mounting Type	Through Hole	Through Hole	Through Hole
Product Status	Active	Active	Obsolete
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant
Inventory	2200 Pcs	10400 Pcs	721 Pcs

Engineering Selection Recommendations

JANTX4N49A is the primary substitute for the 4N49. Both parts are active products with ROHS3 compliance and identical electrical specifications. JANTX4N49A offers improved rise and fall time performance (20µs maximum versus 25µs typical) and greater inventory availability (10400 units).

4N49TX meets all electrical and mechanical parameters but carries obsolete product status and RoHS non-compliance. This part should be avoided for new designs and applications requiring regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can JANTX4N49A replace 4N49 in existing designs? A: Yes. JANTX4N49A is a parametric equivalent with identical isolation voltage, current transfer ratio, output voltage, output current, saturation voltage, and operating temperature range. The TO-78-6 metal can package and through-hole mounting are identical. JANTX4N49A offers faster switching characteristics (20µs rise/fall time versus 25µs).

Q: What is the difference between 4N49 and 4N49TX? A: Both parts share identical electrical specifications and package type. The primary differences are product status (4N49 is active; 4N49TX is obsolete) and regulatory compliance (4N49 is ROHS3 compliant; 4N49TX is RoHS non-compliant). For new applications, 4N49 or JANTX4N49A are preferred.

Q: Are all substitute parts pin-compatible? A: Yes. All listed parts use the TO-78-6 metal can package with identical pinout and through-hole mounting configuration, ensuring direct mechanical and electrical compatibility.

Q: Does switching speed affect substitution suitability? A: JANTX4N49A has faster specified rise and fall times (20µs maximum) compared to 4N49 (25µs typical). This represents improved performance and does not restrict substitution. Applications requiring specific switching speed characteristics should verify compatibility with circuit timing requirements.

Q: What compliance certifications apply to substitute parts? A: 4N49 and JANTX4N49A are both ROHS3 compliant and REACH unaffected. 4N49TX is RoHS non-compliant and should not be used in applications requiring regulatory compliance.

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