LM27952SD LED Driver IC Equivalent & Substitute Parts

Part Overview

The LM27952SD is a 4-output LED driver IC with integrated DC-DC regulator using switched capacitor (charge pump) topology for PWM dimming applications. Manufactured by Texas Instruments, this component is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The LM27952SD operates from 3V to 5.5V supply voltage with 30mA per-channel output current and 750kHz switching frequency, designed primarily for backlight applications in portable electronics.

Substiute Parts

LM27952SD

Texas InstrumentsIn Stock: 4813LM27952SD Datasheet

Current PartRFQ

LM27952SD/NOPB

National SemiconductorIn Stock: 8348LM27952SD/NOPB Datasheet

DirectRFQ

LM27951SD/NOPB

Texas InstrumentsIn Stock: 6268LM27951SD/NOPB Datasheet

Parametric EquivalentRFQ

LM27951SDX/NOPB

Texas InstrumentsIn Stock: 3296LM27951SDX/NOPB Datasheet

Parametric EquivalentRFQ

LM27952SDX/NOPB

Texas InstrumentsIn Stock: 1511LM27952SDX/NOPB Datasheet

Parametric EquivalentRFQ

ADM8843ACPZ-REEL7

Analog Devices Inc.In Stock: 10605ADM8843ACPZ-REEL7 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the LM27952SD is determined by strict alignment of the following critical parameters:

Electrical Compatibility Requirements:

• Number of outputs: 4 channels
• Topology: Switched capacitor (charge pump)
• Dimming control: PWM
• Operating temperature range: -40°C ~ 85°C
• Supply voltage range: 3V to 5.5V (minimum)
• Output voltage range: 2.5V ~ 3.9V
• Output current per channel: 30mA (minimum)

Mechanical Compatibility Requirements:

• Package type: 14-WFDFN Exposed Pad or equivalent footprint
• Mounting type: Surface mount
• Pin count and pitch compatibility

Substitute parts are grouped into three categories based on substitution type:

1. Direct Manufacturer Equivalent (LM27952SD/NOPB): Identical part number with NOPB designation, same electrical and mechanical specifications, different product status (Active vs. Obsolete).

2. Parametric Equivalents (LM27951SD/NOPB, LM27951SDX/NOPB, LM27952SDX/NOPB): Texas Instruments parts with identical or superior electrical performance, same package, different base part numbers or packaging formats (Tape & Reel).

3. Manufacturer Recommended Alternative (ADM8843ACPZ-REEL7): Analog Devices part with similar functional topology but different package type (16-LFCSP-VQ), lower per-channel current (20mA vs. 30mA), and higher switching frequency (1.5MHz vs. 750kHz).

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Same Footprint, Same Electrical Performance):

LM27952SD/NOPB is the primary direct equivalent. This part maintains identical electrical specifications and package footprint while offering Active product status. Selection of this part eliminates obsolescence risk without requiring PCB redesign.

LM27952SDX/NOPB provides an alternative with identical electrical performance and Active status, differentiated by Tape & Reel packaging format. This variant is suitable for high-volume production environments requiring automated component handling.

For Enhanced Compliance:

LM27951SD/NOPB and LM27951SDX/NOPB are Texas Instruments parametric equivalents with ROHS3 compliance certification. These parts feature a lower minimum supply voltage (2.8V vs. 3V), providing expanded operating range while maintaining identical output current, frequency, and package specifications. Both are Active products suitable for new designs requiring RoHS compliance.

For Alternative Topology (Package Change Required):

ADM8843ACPZ-REEL7 from Analog Devices represents a manufacturer-recommended alternative with functional equivalence but different package type (16-LFCSP-VQ vs. 14-WSON). This substitution requires PCB redesign due to different pin count (16 vs. 14) and footprint. The ADM8843 operates at higher switching frequency (1.5MHz) and lower per-channel current (20mA vs. 30mA), making it suitable for applications where reduced output current is acceptable and higher frequency operation is beneficial. ROHS3 compliance and higher MSL rating (3 vs. 1) apply.

Compliance Considerations:

The original LM27952SD is RoHS non-compliant. For new designs or applications requiring regulatory compliance, selection of LM27951SD/NOPB, LM27951SDX/NOPB, LM27952SDX/NOPB, or ADM8843ACPZ-REEL7 is necessary, all of which carry ROHS3 certification.

Frequently Asked Questions (FAQ)

Q: Can LM27951SD/NOPB directly replace LM27952SD without PCB modification?

A: Yes. Both parts share identical package type (14-WFDFN Exposed Pad, 14-WSON 4x3), pin count, and footprint. The LM27951SD features a lower minimum supply voltage (2.8V vs. 3V), which is a functional enhancement. No PCB redesign is required.

Q: What is the difference between LM27952SD and LM27952SD/NOPB?

A: These are the same part number with different product status. LM27952SD is Obsolete; LM27952SD/NOPB is Active. The NOPB designation indicates "No Plumbum" (lead-free) processing. Electrical and mechanical specifications are identical.

Q: Why does ADM8843ACPZ-REEL7 have lower output current (20mA vs. 30mA)?

A: The ADM8843 is a different IC architecture from Analog Devices with different internal design specifications. While it maintains 4-output LED driver functionality with PWM dimming and charge pump topology, the per-channel current rating is 20mA. This part is suitable only for applications where 20mA per channel meets the design requirement.

Q: Can I use ADM8843ACPZ-REEL7 as a drop-in replacement?

A: No. The ADM8843 uses a different package (16-LFCSP-VQ with 16 pins vs. 14-WSON with 14 pins) and different footprint. PCB redesign is required. Additionally, the lower per-channel current (20mA) must be verified as acceptable for the application.

Q: What does MSL 3 (168 Hours) mean for ADM8843ACPZ-REEL7?

A: Moisture Sensitivity Level 3 indicates the component requires storage in controlled humidity conditions and has a 168-hour floor life after moisture exposure. This is more restrictive than MSL 1 (Unlimited) parts like LM27952SD and LM27951 variants. Handling procedures must account for this requirement.

Q: Are all substitute parts suitable for new designs?

A: LM27951SD/NOPB, LM27951SDX/NOPB, LM27952SDX/NOPB, and ADM8843ACPZ-REEL7 are all Active products suitable for new designs. The original LM27952SD is Obsolete and should not be selected for new designs. For RoHS compliance requirements, LM27951 variants and ADM8843 are compliant; the original LM27952SD is not.

Q: What is the difference between LM27951SDX/NOPB and LM27951SD/NOPB?

A: Both are Texas Instruments LM27951 variants with identical electrical specifications. The primary difference is packaging format: LM27951SD/NOPB is supplied in Tape & Reel format, while LM27951SDX/NOPB designation indicates an alternative packaging variant. Electrical performance and footprint are identical.