CNY172 Optoisolator Transistor with Base Output - Equivalent & Substitute Parts

Part Overview

The CNY172 is a 5300Vrms optoisolator with transistor output and base connection, manufactured by onsemi in 6-SMD surface mount packaging. This component provides galvanic isolation for DC input signals with a single transistor output channel rated for 50mA maximum output current. The CNY172 is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production support. Substitute parts must maintain compatibility across isolation voltage, current transfer ratio, output voltage rating, and thermal operating range while accommodating different mounting technologies and packaging formats.

Key Parameters

Parameter	CNY172 (Main Part)
Manufacturer	onsemi
Product Status	Obsolete
Isolation Voltage	5300Vrms
Number of Channels	1
Current Transfer Ratio (Min/Max)	63% / 125% @ 10mA
Output Type	Transistor with Base
Voltage - Output (Max)	70V
Current - Output / Channel	50mA
Vce Saturation (Max)	300mV
Operating Temperature	-55°C ~ 100°C
Mounting Type	Surface Mount
Package / Case	6-SMD, Gull Wing
Input Type	DC
Voltage - Forward (Vf) (Typ)	1.35V
Current - DC Forward (If) (Max)	100mA

Substitute Part Grouping Explanation

Substitution eligibility for the CNY172 is determined by the following critical parameters:

Primary Compatibility Criteria:

Isolation voltage rating of 5000Vrms or higher
Current transfer ratio minimum of 40% @ 10mA (CNY172 specifies 63% minimum)
Output type: Transistor with Base configuration
Maximum output voltage: 70V
Single channel configuration
DC input type
Operating temperature range encompassing -55°C to 100°C

Secondary Compatibility Considerations:

Output current capability: CNY172 rated 50mA; substitutes rated 50mA or 150mA are acceptable
Vce saturation: CNY172 specifies 300mV maximum; substitutes up to 400mV are functionally compatible
Forward voltage (Vf): CNY172 specifies 1.35V typical; substitutes ranging 1.2V to 1.45V are acceptable
Maximum forward current: CNY172 specifies 100mA; substitutes with 60mA or higher are acceptable
Mounting technology: Surface mount (original) to through-hole (substitutes) requires PCB redesign consideration

Substitutes are grouped into two categories:

Direct Functional Equivalents - Parts meeting all primary criteria with minimal parameter variance
Compatible Alternatives - Parts meeting primary criteria with acceptable secondary parameter differences

The CNY172M (onsemi, through-hole DIP) serves as the direct manufacturer equivalent with reduced isolation voltage (4170Vrms). All other substitutes are cross-manufacturer alternatives from Lite-On Inc., Broadcom Limited, Isocom Components 2004 LTD, and Vishay Semiconductor Opto Division, offering 5000Vrms to 5300Vrms isolation ratings.

Parameter Comparison

Part Number	Manufacturer	Isolation Voltage	CTR Min/Max @ 10mA	Output Current	Vce Sat (Max)	Operating Temp	Mounting Type	Package	Product Status
CNY172	onsemi	5300Vrms	63% / 125%	50mA	300mV	-55°C ~ 100°C	Surface Mount	6-SMD	Obsolete
CNY172M	onsemi	4170Vrms	63% / 125%	50mA	400mV	-40°C ~ 100°C	Through Hole	6-DIP	Active
CNY17-1	Lite-On Inc.	5000Vrms	40% / 80%	150mA	300mV	-55°C ~ 100°C	Through Hole	6-DIP	Active
CNY17-1-000E	Broadcom Limited	5000Vrms	40% / 80%	150mA	300mV	-55°C ~ 100°C	Through Hole	6-DIP	Active
CNY17-1-060E	Broadcom Limited	5000Vrms	40% / 80%	150mA	300mV	-55°C ~ 100°C	Through Hole	6-DIP	Active
CNY17-1X	Isocom Components 2004 LTD	5300Vrms	40% / 80%	50mA	400mV	-55°C ~ 100°C	Through Hole	6-DIP	Active
CNY17-1X001	Vishay Semiconductor Opto Division	5000Vrms	40% / 80%	50mA	400mV	-55°C ~ 110°C	Through Hole	6-DIP	Active
CNY17-2	Lite-On Inc.	5000Vrms	63% / 125%	150mA	300mV	-55°C ~ 100°C	Through Hole	6-DIP	Active
CNY17-2-000E	Broadcom Limited	5000Vrms	63% / 125%	150mA	300mV	-55°C ~ 100°C	Through Hole	6-DIP	Active
CNY17-2X	Isocom Components 2004 LTD	5300Vrms	63% / 125%	50mA	400mV	-55°C ~ 100°C	Through Hole	6-DIP	Active
CNY17-2X001	Vishay Semiconductor Opto Division	5000Vrms	63% / 125%	50mA	400mV	-55°C ~ 110°C	Through Hole	6-DIP	Active

Engineering Selection Recommendations

For Direct Replacement (Minimum Redesign): CNY172M is the primary substitute from onsemi. It maintains the same manufacturer lineage and current transfer ratio specification (63% / 125% @ 10mA). The isolation voltage reduction from 5300Vrms to 4170Vrms is acceptable for applications not requiring the full 5300Vrms rating. The transition from surface mount to through-hole packaging requires PCB layout modification. Operating temperature minimum increases from -55°C to -40°C; verify application requirements. Product status is Active, ensuring long-term availability.

For High Current Transfer Ratio Matching (63% / 125% @ 10mA): CNY17-2 (Lite-On Inc.) and CNY17-2-000E (Broadcom Limited) provide identical current transfer ratio specifications to the CNY172. Both are rated 5000Vrms isolation voltage and support 150mA output current. CNY17-2X (Isocom Components 2004 LTD) and CNY17-2X001 (Vishay Semiconductor Opto Division) maintain the 63% / 125% CTR specification with 5300Vrms or 5000Vrms isolation ratings respectively. All are Active status products. Through-hole packaging requires PCB redesign.

For Lower Current Transfer Ratio Tolerance (40% / 80% @ 10mA): CNY17-1 (Lite-On Inc.), CNY17-1-000E (Broadcom Limited), CNY17-1-060E (Broadcom Limited), CNY17-1X (Isocom Components 2004 LTD), and CNY17-1X001 (Vishay Semiconductor Opto Division) offer reduced current transfer ratio specifications. These parts are suitable for applications where lower CTR is acceptable. CNY17-1 and CNY17-1-000E support 150mA output current; CNY17-1X and CNY17-1X001 are rated 50mA. All are Active status products with 5000Vrms to 5300Vrms isolation ratings.

Compliance and Certification: All substitute parts carry REACH Unaffected status and EAR99 ECCN classification, matching the CNY172. RoHS3 compliance is confirmed for all active substitutes. Moisture sensitivity level (MSL) is 1 (Unlimited) for all parts, indicating no special moisture handling requirements.

Frequently Asked Questions (FAQ)

Q: Can CNY172M replace CNY172 directly without PCB modification? A: No. CNY172M uses through-hole 6-DIP packaging while CNY172 is surface mount 6-SMD. PCB footprint and layout changes are required. Electrical parameters are compatible with noted isolation voltage reduction (4170Vrms vs. 5300Vrms).

Q: What is the difference between CNY17-1 and CNY17-2 series substitutes? A: The primary difference is current transfer ratio specification. CNY17-1 series specifies 40% / 80% @ 10mA, while CNY17-2 series specifies 63% / 125% @ 10mA. CNY17-2 series matches the CNY172 CTR specification more closely. Both series support 150mA output current and 5000Vrms isolation voltage.

Q: Are Lite-On Inc., Broadcom Limited, Isocom Components, and Vishay parts interchangeable? A: Yes, within the same CTR specification group. Parts with identical isolation voltage, current transfer ratio range, output current rating, and operating temperature range are functionally interchangeable. Verify specific part number suffixes (-000E, -060E, -1X, -2X, etc.) as these indicate manufacturing variants and may have minor parameter differences.

Q: Does the CNY172 require a specific isolation voltage rating for my application? A: The CNY172 is rated 5300Vrms. Substitutes range from 4170Vrms (CNY172M) to 5300Vrms (CNY17-1X, CNY17-2X). Select a substitute with isolation voltage equal to or exceeding your application requirement. Lower isolation voltage substitutes are acceptable only if your circuit design does not require the full 5300Vrms rating.

Q: What is the impact of Vce saturation differences between CNY172 and substitutes? A: CNY172 specifies 300mV maximum Vce saturation. Some substitutes specify 400mV maximum. This 100mV difference affects output voltage swing and power dissipation in the transistor. For applications sensitive to saturation voltage, select substitutes with 300mV maximum specification (CNY172M, CNY17-1, CNY17-1-000E, CNY17-1-060E, CNY17-2, CNY17-2-000E).

Q: Can I use CNY17-1 series (40% / 80% CTR) in place of CNY172 (63% / 125% CTR)? A: Only if your circuit design accommodates the lower current transfer ratio. CNY17-1 series provides minimum 40% CTR compared to CNY172 minimum 63% CTR. This affects input current requirements and circuit gain calculations. Verify your application tolerates the reduced CTR before substitution.

Q: What are the temperature operating range differences? A: CNY172 operates -55°C to 100°C. CNY172M operates -40°C to 100°C (higher minimum). CNY17-1X001 and CNY17-2X001 (Vishay) operate -55°C to 110°C (higher maximum). Select substitutes matching or exceeding your application temperature requirements.

Q: Is RoHS3 compliance required for my application? A: All active substitute parts are RoHS3 compliant. The obsolete CNY172 does not specify RoHS status. If RoHS3 compliance is mandatory, select from active status substitutes: CNY172M, CNY17-1, CNY17-1-000E, CNY17-1-060E, CNY17-1X, CNY17-1X001, CNY17-2, CNY17-2-000E, CNY17-2X, or CNY17-2X001.

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