FAN5609MPX Equivalent & Substitute Parts

Part Overview

The FAN5609MPX is a 4-output LED driver IC with integrated DC-DC regulator using switched capacitor (charge pump) topology. Manufactured by onsemi, this component operates across a 2.7V to 5.5V supply range with 20mA per-channel output capability and PWM dimming functionality for backlight applications. The part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production support.

Key Parameters

Parameter	FAN5609MPX
Manufacturer	onsemi
Category	Power Management (PMIC)
Type	DC DC Regulator
Topology	Switched Capacitor (Charge Pump)
Number of Outputs	4
Voltage - Supply (Min)	2.7V
Voltage - Supply (Max)	5.5V
Current - Output / Channel	20mA
Frequency	1MHz
Dimming	PWM
Operating Temperature	-40°C ~ 85°C (TA)
Package / Case	16-VQFN Exposed Pad
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the FAN5609MPX is determined by the following critical parameters:

Functional Category: LED driver IC with 4-output DC-DC regulator topology
Dimming Control: PWM capability required
Number of Outputs: 4 channels
Supply Voltage Range: Minimum 2.7V to 5.5V maximum (or compatible overlap)
Output Current: 20mA per channel minimum
Mounting Type: Surface mount
Applications: Backlight LED driving

The three substitute parts listed below meet these core functional requirements while operating within acceptable electrical parameter ranges for LED driver applications. Topology differences (Step-Up Boost vs. Switched Capacitor) are acceptable where supply voltage and output current specifications overlap with the original design envelope.

Parameter Comparison

Parameter	FAN5609MPX	A8519KLPTR-T	ISL97684IRTZ	MP3384EQ-LF-P
Manufacturer	onsemi	Allegro MicroSystems	Renesas Electronics	Monolithic Power Systems
Topology	Switched Capacitor (Charge Pump)	Step-Up (Boost)	Step-Up (Boost)	Step-Up (Boost)
Number of Outputs	4	4	4	4
Voltage - Supply (Min)	2.7V	4.5V	4V	4.5V
Voltage - Supply (Max)	5.5V	40V	26.5V	25V
Current - Output / Channel	20mA	100mA	50mA	40mA
Frequency	1MHz	200kHz ~ 2.15MHz	600kHz	1.25MHz
Dimming	PWM	Analog, PWM	PWM	PWM
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 125°C (TA)	-40°C ~ 85°C (TA)	-40°C ~ 125°C (TJ)
Package / Case	16-VQFN Exposed Pad	20-TSSOP Exposed Pad	16-WFQFN Exposed Pad	16-VFQFN Exposed Pad
Product Status	Obsolete	Active	Active	Not For New Designs

Engineering Selection Recommendations

A8519KLPTR-T (Allegro MicroSystems): Active product status with automotive-grade qualification (AEC-Q100). Supports extended temperature range (-40°C to 125°C). Output current capability (100mA) exceeds FAN5609MPX requirements. Supply voltage minimum of 4.5V is higher than the original 2.7V, requiring circuit redesign for low-voltage applications. 20-TSSOP package differs from original 16-VQFN footprint. Suitable for automotive and industrial backlight applications with adequate supply voltage.

ISL97684IRTZ (Renesas Electronics Corporation): Active product with ROHS3 compliance. Maintains original operating temperature range (-40°C to 85°C). Output current (50mA) provides 2.5× margin over FAN5609MPX. Supply voltage minimum of 4V is compatible with most battery-powered and regulated supply designs. 16-TQFN package footprint is similar to original 16-VQFN, reducing PCB redesign effort. Recommended for direct replacement in designs with supply voltage ≥4V.

MP3384EQ-LF-P (Monolithic Power Systems Inc.): Not For New Designs status limits suitability for new product development. ROHS3 compliant with extended temperature capability (-40°C to 125°C). Output current (40mA) provides 2× margin. Supply voltage minimum of 4.5V requires circuit evaluation. 16-VFQFN package is pin-compatible with original footprint. Acceptable for legacy product support and maintenance applications only.

Frequently Asked Questions (FAQ)

Q: Can the A8519KLPTR-T replace the FAN5609MPX in a 3.3V supply design?

A: No. The A8519KLPTR-T minimum supply voltage is 4.5V, which exceeds typical 3.3V rail availability. The ISL97684IRTZ with 4V minimum is a better choice for 3.3V designs, though circuit validation is required.

Q: What is the primary difference between the FAN5609MPX topology and the substitute parts?

A: The FAN5609MPX uses switched capacitor (charge pump) topology, while all three substitutes use step-up (boost) topology. Both topologies are suitable for LED driver applications. Charge pump designs typically have lower EMI but limited output voltage capability. Boost converters provide higher output voltage and current capacity with potentially higher EMI.

Q: Are the substitute parts pin-compatible with the FAN5609MPX?

A: No. The FAN5609MPX uses 16-VQFN packaging. The ISL97684IRTZ uses 16-TQFN (similar footprint, different pinout). The A8519KLPTR-T uses 20-TSSOP (larger package). The MP3384EQ-LF-P uses 16-VFQFN (similar footprint). PCB redesign and schematic validation are required for all substitutions.

Q: Which substitute is recommended for new designs?

A: The ISL97684IRTZ is recommended for new designs. It maintains active product status, provides adequate performance margin, and operates within the original temperature range. The 16-TQFN package minimizes PCB redesign effort compared to other options.

Q: Do all substitutes support PWM dimming?

A: Yes. All three substitutes support PWM dimming. The A8519KLPTR-T additionally supports analog dimming, providing design flexibility not available in the original FAN5609MPX.

Q: What is the impact of higher output current capability in the substitutes?

A: The substitutes provide 40mA to 100mA per-channel output, compared to 20mA in the FAN5609MPX. This allows driving higher-brightness LED strings or additional LED channels without exceeding device ratings. Existing designs can operate at reduced current levels without performance degradation.

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