RT9361BGE LED Driver IC Equivalent & Substitute Parts

Part Overview

The RT9361BGE is an active LED driver IC manufactured by Richtek USA Inc., designed for camera flash applications. It functions as a 1-output DC-DC regulator using switched capacitor (charge pump) topology with PWM dimming capability. The device operates from a 2.8V to 4.5V supply and delivers up to 500mA switch current at 4.5V output, operating at 1MHz switching frequency. With 2945 units in stock and ROHS3 compliance, this part remains actively available. Equivalent and substitute parts are identified for applications requiring alternative topologies, package formats, current ratings, or supply voltage ranges while maintaining core LED driver functionality.

Key Parameters

Parameter	RT9361BGE
Manufacturer	Richtek USA Inc.
Category	Power Management (PMIC)
Type	DC DC Regulator
Topology	Switched Capacitor (Charge Pump)
Package	SOT-23-6
Voltage Supply (Min)	2.8V
Voltage Supply (Max)	4.5V
Voltage Output	4.5V
Current Output / Channel	500mA (Switch)
Switching Frequency	1MHz
Dimming Control	PWM
Applications	Camera Flash
Operating Temperature	-40°C ~ 85°C (TA)
RoHS Status	ROHS3 Compliant
MSL Rating	3 (168 Hours)
Product Status	Active

Substitute Part Grouping Explanation

Substitution logic for the RT9361BGE is based on the following allowed parameters: topology type (switched capacitor charge pump, step-up boost, step-down buck, or SEPIC), supply voltage range compatibility, output current capability, switching frequency, dimming control method (PWM, I2C, or analog), package format, and operating temperature range. Parts are grouped into three categories:

Category 1: Direct Topology Match (Switched Capacitor Charge Pump) Parts maintaining identical switched capacitor topology with PWM dimming for camera flash and backlight applications. These offer the closest functional equivalence.

Category 2: Alternative Topology - Step-Up (Boost) Parts using step-up boost topology with PWM or analog dimming. These provide higher output voltage capability and are suitable when supply voltage remains within compatible ranges (2.5V to 6V).

Category 3: Alternative Topology - Step-Down (Buck) and SEPIC Parts using buck or SEPIC topologies for different voltage conversion requirements. These are applicable when input supply voltage exceeds 4.5V and lower output voltages are acceptable.

Substitution eligibility requires: (1) overlapping supply voltage range with RT9361BGE (minimum 2.8V to 4.5V window), (2) output current rating of at least 350mA for direct replacement or application-specific requirements, (3) compatible package footprint or acceptable PCB redesign, (4) matching or superior operating temperature range, and (5) equivalent or better RoHS and MSL compliance.

Parameter Comparison

Part Number	Manufacturer	Topology	Package	Voltage Supply Min	Voltage Supply Max	Current Output	Frequency	Dimming	Temp Range	RoHS	MSL	Status
RT9361BGE	Richtek USA Inc.	Switched Capacitor (Charge Pump)	SOT-23-6	2.8V	4.5V	500mA (Switch)	1MHz	PWM	-40°C ~ 85°C	ROHS3	3	Active
SP7685ER-L/TR	MaxLinear, Inc.	Switched Capacitor (Charge Pump)	10-DFN (3x3)	2.7V	5.5V	1.2A (Flash)	2.4MHz	PWM	-40°C ~ 85°C	RoHS	1	Last Time Buy
LTC3202EDD#PBF	Analog Devices Inc.	Switched Capacitor (Charge Pump)	10-DFN (3x3)	2.7V	4.5V	125mA	1.5MHz	PWM	-40°C ~ 85°C	ROHS3	1	Active
MP1518DJ-LF-Z	Monolithic Power Systems Inc.	Step-Up (Boost)	TSOT-23-6	2.5V	6V	350mA (Switch)	1.3MHz	Analog, PWM	-40°C ~ 125°C	ROHS3	1	Active
LM3405XMK/NOPB	Texas Instruments	Step-Down (Buck)	TSOT-23-6	3V	15V	1A	1.6MHz	PWM	-40°C ~ 125°C	ROHS3	1	Active
ADP1655ACBZ-R7	Analog Devices Inc.	Step-Up (Boost)	12-WLCSP (1.5x2)	2.7V	5.5V	500mA (Flash)	2MHz	I2C	-40°C ~ 85°C	ROHS3	1	Active
LM3410YMYE/NOPB	Texas Instruments	SEPIC, Step-Up (Boost)	8-HVSSOP	2.7V	5.5V	2.8A (Switch)	525kHz	PWM	-40°C ~ 125°C	ROHS3	1	Active
LT3593ES6#TRMPBF	Analog Devices Inc.	Step-Up (Boost)	TSOT-23-6	2.7V	5.5V	45mA	1MHz	—	-40°C ~ 85°C	ROHS3	1	Active
AL8861Y-13	Diodes Incorporated	Step-Down (Buck)	SOT-89-5	4.5V	40V	1.5A	1MHz	Analog, PWM	-40°C ~ 85°C	ROHS3	3	Active
MP2410GJ-P	Monolithic Power Systems Inc.	Step-Down (Buck)	TSOT-23-6	4.2V	24V	2A	1MHz	Analog	-40°C ~ 125°C	ROHS3	1	Active
MP3310NGQ-P	Monolithic Power Systems Inc.	Step-Up (Boost)	10-QFN (3x3)	4.5V	25V	1.3A (Switch)	1MHz	PWM	-20°C ~ 125°C	ROHS3	1	Active

Engineering Selection Recommendations

For Direct Replacement (Switched Capacitor Topology with PWM Dimming):

SP7685ER-L/TR offers the closest functional match with identical switched capacitor charge pump topology and PWM dimming. It provides 1.2A flash current versus 500mA, operates across 2.7V to 5.5V supply range, and maintains -40°C to 85°C temperature specification. However, SP7685ER-L/TR carries Last Time Buy status, indicating discontinued production. LTC3202EDD#PBF provides an active alternative with switched capacitor topology and PWM dimming, though output current is limited to 125mA, suitable only for lower-power camera flash applications.

For Higher Current Capability (Step-Up Boost Topology):

MP1518DJ-LF-Z and ADP1655ACBZ-R7 both deliver 350mA to 500mA output current using step-up boost topology. MP1518DJ-LF-Z operates from 2.5V to 6V with PWM/analog dimming and maintains TSOT-23-6 package compatibility. ADP1655ACBZ-R7 provides 500mA flash current with I2C dimming control but requires 12-WLCSP package redesign. Both are ROHS3 compliant with MSL 1 rating and active product status.

For Extended Supply Voltage Range:

LM3410YMYE/NOPB supports 2.7V to 5.5V input with SEPIC/boost topology, delivering 2.8A switch current. This part accommodates wider input voltage variation and higher current demands but requires 8-HVSSOP package redesign. Operating temperature extends to 125°C (TJ).

For Buck Topology Applications (Higher Input Voltage):

LM3405XMK/NOPB and MP2410GJ-P provide step-down buck regulation for applications with input voltage exceeding 4.5V. LM3405XMK/NOPB operates 3V to 15V with 1A output and maintains TSOT-23-6 package. MP2410GJ-P supports 4.2V to 24V with 2A output and analog dimming. Both extend operating temperature to 125°C (TJ).

Compliance and Reliability Considerations:

All recommended active substitutes maintain ROHS3 compliance. Parts with MSL 1 rating (MP1518DJ-LF-Z, ADP1655ACBZ-R7, LM3410YMYE/NOPB, LT3593ES6#TRMPBF, LTC3202EDD#PBF, MP2410GJ-P, MP3310NGQ-P) offer superior moisture handling compared to RT9361BGE (MSL 3). SP7685ER-L/TR and AL8861Y-13 match MSL 3 rating but SP7685ER-L/TR is discontinued.

Frequently Asked Questions (FAQ)

Q: Can SP7685ER-L/TR directly replace RT9361BGE in production?

A: SP7685ER-L/TR provides functional equivalence with identical switched capacitor topology and PWM dimming, supporting the same -40°C to 85°C temperature range. However, SP7685ER-L/TR is Last Time Buy status, indicating production discontinuation. For new designs, LTC3202EDD#PBF offers active switched capacitor alternative, though with reduced 125mA output current suitable only for lower-power applications.

Q: What is the key difference between charge pump and boost topologies?

A: Switched capacitor (charge pump) topology uses capacitive energy transfer without inductors, enabling compact packages like SOT-23-6 and 10-DFN. Step-up (boost) topology uses inductive energy storage, typically requiring larger packages but offering higher current capability and wider voltage conversion ratios. RT9361BGE uses charge pump; MP1518DJ-LF-Z and ADP1655ACBZ-R7 use boost topology.

Q: Can I use a buck converter to replace RT9361BGE?

A: Buck converters step down voltage and require input voltage higher than desired output. RT9361BGE outputs 4.5V from 2.8V to 4.5V input, requiring charge pump or boost topology. Buck converters like LM3405XMK/NOPB or MP2410GJ-P are applicable only when input voltage exceeds output voltage requirement, typically for backlight or high-voltage LED applications.

Q: What does MSL rating mean for component selection?

A: MSL (Moisture Sensitivity Level) indicates how long a component can be exposed to ambient conditions before soldering. MSL 1 (unlimited) allows indefinite storage; MSL 3 (168 hours) requires soldering within 168 hours of package opening. RT9361BGE is MSL 3; most active substitutes are MSL 1, offering better shelf-life and manufacturing flexibility.

Q: Is package compatibility critical for substitution?

A: Package compatibility depends on PCB design constraints. RT9361BGE uses SOT-23-6; direct footprint matches include MP1518DJ-LF-Z and LM3405XMK/NOPB (both TSOT-23-6). Alternative packages like 10-DFN (SP7685ER-L/TR, LTC3202EDD#PBF) or 12-WLCSP (ADP1655ACBZ-R7) require PCB redesign but may offer superior thermal or electrical performance.

Q: Why do some substitutes have different dimming control methods?

A: Dimming control method (PWM, I2C, analog) determines how LED brightness is adjusted. RT9361BGE uses PWM dimming via external signal. ADP1655ACBZ-R7 uses I2C digital control, requiring microcontroller interface. MP1518DJ-LF-Z supports both analog and PWM. Selection depends on system architecture and control requirements.

Q: What is the significance of operating temperature range differences?

A: RT9361BGE operates -40°C to 85°C (TA, ambient). Many substitutes extend to 125°C (TJ, junction temperature), indicating superior thermal performance and reliability in high-temperature environments. Extended temperature range is beneficial for automotive, industrial, or high-brightness LED applications.

Q: Can I use LT3593ES6#TRMPBF as a direct replacement?

A: LT3593ES6#TRMPBF uses step-up boost topology with only 45mA output current, significantly lower than RT9361BGE's 500mA. It is suitable only for ultra-low-power backlight applications, not camera flash. Direct replacement is not recommended for equivalent performance.

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