STCH02 Equivalent & Substitute Parts

Part Overview

The STCH02 is an offline switch flyback converter IC manufactured by STMicroelectronics, designed for isolated power management applications using flyback topology. This component operates at 260kHz switching frequency with a supply voltage range of 11.5V to 23V and includes over-voltage fault protection. The STCH02 is classified as obsolete, necessitating identification of active equivalent parts for new designs and ongoing production requirements. Substitute parts must maintain functional compatibility across topology, isolation characteristics, packaging, and thermal operating range.

Substiute Parts

STCH02

STMicroelectronicsIn Stock: 1111STCH02 Datasheet

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STCH03

STMicroelectronicsIn Stock: 3126STCH03 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the STCH02 is determined by strict equivalence across the following critical parameters:

Topology & Isolation: Both the main part and substitute must operate as isolated flyback converters with identical output isolation characteristics.

Package & Mounting: Physical compatibility requires identical package type (8-SOIC), case dimensions (0.154", 3.90mm width), and surface mount mounting type.

Supply Voltage Range: The substitute must operate within the specified 11.5V to 23V supply voltage window to ensure circuit compatibility.

Operating Temperature: The substitute must support the full -25°C to 125°C junction temperature range.

Compliance & Environmental: Both parts must maintain ROHS3 compliance, identical MSL rating (3), and equivalent regulatory status (REACH Unaffected, EAR99).

Duty Cycle: Both parts operate at 50% duty cycle.

The STCH03 qualifies as a substitute based on these criteria, despite differences in switching frequency (196kHz versus 260kHz) and startup voltage (17V versus 13V), as these parameters fall within acceptable design variation ranges for flyback converter applications with the specified supply voltage envelope.

Parameter Comparison

Engineering Selection Recommendations

The STCH03 is the qualified substitute for the obsolete STCH02 based on the following engineering criteria:

Product Status: The STCH02 is classified as obsolete, making the active STCH03 the appropriate replacement for ongoing production and new design implementations.

Regulatory Compliance: Both parts maintain identical ROHS3 compliance, REACH unaffected status, and EAR99 export classification, ensuring equivalent regulatory standing across all markets.

Package Compatibility: Identical 8-SOIC packaging and surface mount characteristics enable direct PCB layout compatibility without redesign.

Electrical Envelope: Both parts operate within the identical 11.5V to 23V supply voltage range and -25°C to 125°C thermal operating window, ensuring circuit-level compatibility.

Enhanced Protection: The STCH03 provides additional over-current fault protection in addition to over-voltage protection, offering improved system reliability compared to the STCH02.

Switching Frequency Variation: The STCH03 operates at 196kHz versus the STCH02's 260kHz. This frequency difference requires transformer and filter component recalculation but does not preclude substitution within the specified supply voltage and thermal parameters.

Startup Voltage Consideration: The STCH03 requires 17V startup voltage compared to the STCH02's 13V. Circuit design must ensure adequate bias supply voltage to meet this requirement.

Frequently Asked Questions (FAQ)

Q: Can the STCH03 be used as a direct pin-for-pin replacement for the STCH02?

A: Both parts use identical 8-SOIC packaging with matching pin assignments for flyback converter applications. Pin compatibility is maintained. However, the different switching frequencies (196kHz versus 260kHz) require recalculation of transformer and output filter components to maintain equivalent performance characteristics.

Q: What is the impact of the 196kHz switching frequency in the STCH03 compared to the STCH02's 260kHz?

A: Lower switching frequency reduces EMI generation and core losses but increases transformer size and output filter capacitance requirements. Circuit design must be adjusted accordingly. The lower frequency does not affect supply voltage compatibility or thermal operating range.

Q: Does the STCH03's higher startup voltage (17V versus 13V) affect circuit design?

A: Yes. The bias supply circuit must provide sufficient voltage to reach 17V for the STCH03 to initiate operation. Designs operating with marginal bias supplies below 17V cannot use the STCH03 without circuit modification.

Q: Are there any differences in fault protection between these parts?

A: The STCH02 provides over-voltage protection only. The STCH03 provides both over-current and over-voltage protection, offering enhanced system protection without additional external components.

Q: Is the STCH03 available in the same packaging options as the STCH02?

A: Both parts are supplied in 8-SOIC surface mount packages with identical case dimensions (0.154", 3.90mm width). The STCH03 is available in tube packaging, while the STCH02 packaging format is not specified in the provided data.

Q: Do both parts meet the same environmental and compliance standards?

A: Yes. Both the STCH02 and STCH03 are ROHS3 compliant, REACH unaffected, classified as EAR99, and maintain identical MSL 3 (168 hours) moisture sensitivity ratings.

Q: What is the primary reason for substituting the STCH02 with the STCH03?

A: The STCH02 is obsolete. The STCH03 is an active product from the same manufacturer with equivalent electrical and mechanical specifications, making it the appropriate replacement for production continuity and new designs.