RT7320GSP LED Driver IC Equivalent & Substitute Parts

Part Overview

The RT7320GSP is an AC DC offline switcher LED driver IC manufactured by Richtek USA Inc., designed for single-output lighting applications with a maximum output current of 78.3mA. The device operates across a wide supply voltage range of 0V to 100V and is housed in an 8-SOP-EP package with an exposed pad for thermal management. The RT7320GSP is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and production continuity.

Key Parameters

Parameter	RT7320GSP
Manufacturer	Richtek USA Inc.
Category	Power Management (PMIC)
Type	AC DC Offline Switcher
Number of Outputs	1
Voltage Supply Range	0V to 100V
Current Output / Channel	78.3mA
Internal Switch(s)	Yes
Operating Temperature	-40°C to 85°C (TA)
Package / Case	8-SOIC (0.154", 3.90mm Width) Exposed Pad
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
MSL Rating	3 (168 Hours)

Substitute Part Grouping Explanation

Substitution of the RT7320GSP is determined by the following critical parameters:

Primary Substitution Criteria:

AC DC offline switcher topology with single output
Internal switching capability (integrated power switch)
Operating temperature range compatibility (-40°C minimum)
Surface mount package compatibility or functional equivalence
RoHS3 compliance and REACH unaffected status

Secondary Compatibility Factors:

Supply voltage range overlap with 0V to 100V specification
Output current capability at or above 78.3mA
Dimming capability (if required by application)
Moisture sensitivity level (MSL 3 acceptable)

The substitute parts listed below meet the core functional requirements of an AC DC offline switcher LED driver with single output and internal switching capability. Variations in topology (Flyback, Buck, SEPIC, Boost), dimming method (PWM, Triac), and package form factor represent design trade-offs that may be acceptable depending on circuit board layout and application requirements.

Parameter Comparison

Parameter	RT7320GSP	LM3497MMX/NOPB	LNK414LG	LNK417LG	NCL30188ADR2G	NCL30188BDR2G
Manufacturer	Richtek USA Inc.	Texas Instruments	Power Integrations	Power Integrations	onsemi	onsemi
Type	AC DC Offline Switcher	AC DC Offline Switcher	AC DC Offline Switcher	AC DC Offline Switcher	AC DC Offline Switcher	AC DC Offline Switcher
Internal Switch(s)	Yes	No	Yes	Yes	No	No
Number of Outputs	1	1	1	1	1	1
Voltage Supply (Min)	0V	8V	36V	36V	8.8V	8.8V
Voltage Supply (Max)	100V	12V	725V	725V	25.5V	25.5V
Current Output / Channel	78.3mA	—	1.02A	1.77A	—	500mA
Operating Temperature (Min)	-40°C	-40°C	-40°C	-40°C	-40°C	-40°C
Operating Temperature (Max)	85°C	125°C	150°C	150°C	125°C	125°C
Mounting Type	Surface Mount	Surface Mount	Through Hole	Through Hole	Surface Mount	Surface Mount
Package / Case	8-SOIC (0.154", 3.90mm Width) Exposed Pad	10-TFSOP, 10-MSOP (0.118", 3.00mm Width)	7-SSIP, 6 Leads, Exposed Pad, Formed Leads	7-SSIP, 6 Leads, Exposed Pad, Formed Leads	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)
Product Status	Obsolete	Active	Active	Active	Obsolete	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	RoHS Compliant	RoHS Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	3 (168 Hours)	3 (168 Hours)

Engineering Selection Recommendations

NCL30188BDR2G (onsemi) — Recommended for direct replacement in existing designs. This part maintains the same 8-SOIC package footprint as the RT7320GSP, surface mount configuration, and MSL 3 rating. The device is currently active in production with ROHS3 compliance. The 500mA output current capability exceeds the RT7320GSP specification of 78.3mA. Supply voltage range (8.8V to 25.5V) is narrower than the original but suitable for standard AC DC offline switcher applications. Operating temperature maximum of 125°C provides improved thermal margin compared to the RT7320GSP at 85°C.

LNK417LG (Power Integrations) — Suitable for applications requiring higher output current (1.77A) and extended operating temperature range (-40°C to 150°C). This part features internal switching capability and PWM dimming. The eSIP-7F package requires through-hole mounting, necessitating circuit board redesign. Supply voltage range (36V to 725V) is significantly higher than the RT7320GSP, making this option appropriate for high-voltage offline switcher designs. Product status is active with unlimited MSL rating.

LNK414LG (Power Integrations) — Alternative for designs requiring lower output current (1.02A) with PWM dimming capability. Similar package and thermal characteristics to LNK417LG. Suitable when circuit board layout permits through-hole mounting conversion.

LM3497MMX/NOPB (Texas Instruments) — Applicable for designs where external switching is acceptable. This part lacks internal switching capability but provides Triac dimming support. Supply voltage range (8V to 12V) is restrictive compared to the RT7320GSP. Package change from 8-SOIC to 10-TFSOP requires board redesign. Product status is active with MSL 1 rating.

NCL30188ADR2G (onsemi) — Functionally similar to NCL30188BDR2G but classified as obsolete. Not recommended for new designs due to product status, though may be considered for legacy system maintenance where inventory is available.

Frequently Asked Questions (FAQ)

Q: Can the NCL30188BDR2G directly replace the RT7320GSP without circuit board modifications?

A: The NCL30188BDR2G shares the same 8-SOIC surface mount package footprint and pinout compatibility with the RT7320GSP, allowing direct PCB placement without layout changes. However, circuit validation is required to confirm functional equivalence, as internal architecture and control schemes may differ between manufacturers.

Q: What is the primary difference between LNK414LG and LNK417LG?

A: Both devices are Power Integrations LinkSwitch-PH series parts with identical topology (Flyback), dimming method (PWM), and package (eSIP-7F). The primary difference is output current rating: LNK414LG provides 1.02A while LNK417LG provides 1.77A. Selection depends on application current requirements.

Q: Why do the LNK414LG and LNK417LG require through-hole mounting while the RT7320GSP uses surface mount?

A: The LNK414LG and LNK417LG employ the eSIP-7F package with formed leads designed for through-hole insertion, whereas the RT7320GSP uses the 8-SOIC package optimized for surface mount assembly. Package selection reflects different manufacturing processes and thermal management strategies employed by each manufacturer.

Q: Is the LM3497MMX/NOPB suitable as a direct substitute?

A: The LM3497MMX/NOPB is functionally different from the RT7320GSP in that it lacks an internal power switch, requiring external switching components. Additionally, the supply voltage range (8V to 12V) is significantly narrower than the RT7320GSP (0V to 100V). This part is suitable only for applications where external switching is already implemented in the design.

Q: What does MSL 3 (168 Hours) mean for the RT7320GSP?

A: MSL 3 indicates Moisture Sensitivity Level 3, meaning the component can be exposed to moisture for a maximum of 168 hours (7 days) at 85°C and 85% relative humidity before baking is required. This is more restrictive than MSL 1 (unlimited), requiring careful handling and storage protocols. Substitute parts with MSL 1 rating (LNK414LG, LNK417LG) offer less stringent moisture management requirements.

Q: Can I use NCL30188ADR2G in a new production design?

A: NCL30188ADR2G is classified as obsolete and should not be selected for new designs. Use NCL30188BDR2G instead, which is currently active in production and offers the same package and electrical characteristics with improved long-term availability.

Q: What are the key electrical differences between the substitute parts?

A: The primary electrical differences are supply voltage range, output current capability, and internal switching presence. The RT7320GSP operates from 0V to 100V with 78.3mA output and integrated switching. Substitutes vary: LNK414LG/LNK417LG support 36V to 725V with 1.02A/1.77A output; NCL30188BDR2G supports 8.8V to 25.5V with 500mA output; LM3497MMX/NOPB supports 8V to 12V without internal switching. Selection must align with the target application's voltage and current requirements.

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