Texas Instruments LM36923HYFFR

Overview

LM36923HYFFR from Texas Instruments is a highly efficient triple-string white LED driver IC for LCD display backlighting, featuring 1% string-to-string current matching, 11-bit dimming resolution, and up to 38 V output capability at 25 mA per string. It operates from 2.5 V to 5.5 V input and supports I²C programming and logic-level PWM control in smartphones and tablets.

For engineers reviewing the LM36923HYFFR datasheet, LM36923HYFFR pinout, LM36923HYFFR application, or LM36923HYFFR equivalent, key selection considerations include its adaptive headroom regulation, selectable OVP thresholds (17/24/31/38 V), auto-switching frequency mode (250/500/1000 kHz), and DSBGA-12 package with 1.756 mm × 1.355 mm footprint.

Technical Context

The LM36923HYFFR integrates an inductive boost converter with three independent current sinks, regulating minimum voltage across LED1–LED3 to maintain headroom (VHR) as low as 35 mV at 5 mA. Its adaptive current regulation allows mismatched forward voltages across strings while preserving ±1% matching.

It implements dual brightness mapping-linear (37.8 µA + 12.195 µA/code) and exponential (50 µA × 1.00304^code)-with PWM sampling at 800 kHz/4 MHz/24 MHz and configurable hysteresis (0–6 LSBs) to suppress jitter-induced current oscillation.

Key Specifications

Pinout & Package

LM36923HYFFR uses a 12-pin DSBGA (YFF) package with 0.4 mm pitch and body size 1.756 mm × 1.355 mm. Thermal resistance R_θJA = 88.9 °C/W enables operation in space-constrained mobile applications without forced airflow.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar white LED driver applications.

Compared with LM36924HYFFR, LM36923HYFFR offers identical footprint and control flexibility but limits per-string current to 25 mA and omits ADIM. Against TPS61165DRCR, it trades single-string simplicity for triple-string matching, I²C configurability, and smaller DSBGA footprint - essential for high-end multi-zone displays.

Availability

LM36923HYFFR is available at Aetrix Electronics and suitable for smartphone backlighting, tablet display systems, and automotive infotainment modules requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM36923HYFFR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader delivering analog and embedded processing solutions, with over 90 years of innovation in power management and signal chain technologies.

The LM36923HYFFR belongs to TI's display backlight driver product line, engineered specifically for high-efficiency, high-accuracy multi-string LED control in portable and automotive LCD applications.

FAQ

What is the maximum LED string voltage supported by the LM36923HYFFR?

The LM36923HYFFR supports up to 38 V output voltage, enabling it to drive up to 12 series-connected white LEDs (assuming typical VF ≈ 3.17 V). This rating is enforced via four programmable overvoltage protection thresholds (17 V, 24 V, 31 V, 38 V), with the 38 V setting allowing full utilization of the boost stage. The OUT pin must be connected directly to the output capacitor's positive terminal for accurate sensing.

How does the LM36923HYFFR achieve 1% current matching between LED strings?

The LM36923HYFFR achieves ±1% string-to-string current matching through factory-trimmed current sink circuitry and adaptive headroom regulation that dynamically adjusts the minimum voltage across each LED string. This design compensates for process, voltage, and temperature variations without external calibration. Matching is specified over 50 µA–25 mA per string and –40°C to +85°C ambient, verified per JEDEC JESD51-1 thermal test conditions.

Can the LM36923HYFFR operate without I²C configuration?

Yes, the LM36923HYFFR can operate stand-alone using only the PWM input. On power-up with HWEN high, it defaults to linear mapping, PWM enable, and chip enable active. The internal 24 MHz PWM sampler converts duty cycle to an 11-bit brightness code, enabling full dimming control without any I²C writes. This mode supports 50 Hz–50 kHz PWM frequencies and includes configurable hysteresis to suppress noise-induced current fluctuations.

What thermal management provisions does the LM36923HYFFR include?

The LM36923HYFFR incorporates thermal shutdown at 135 °C with 15 °C hysteresis, plus junction-to-board thermal resistance (R_θJB) of 43.9 °C/W when the DSBGA thermal pad is properly soldered to PCB copper. Its 88.9 °C/W junction-to-ambient rating assumes standard JEDEC 2-layer board conditions. Layout guidelines require minimum 2.2 µF IN bypass capacitance and direct thermal pad connection to solid ground plane for reliable operation at 25 mA/string continuous load.

Is the LM36923HYFFR pin-compatible with other members of the LM3692x family?

Yes, the LM36923HYFFR shares identical pinout and DSBGA-12 (YFF) package with LM36924HYFFR, enabling drop-in replacement where 25 mA per string and absence of ADIM input are acceptable. Both devices use the same PCB footprint, thermal pad layout, and external component values. However, LM36924HYFFR adds an ADIM pin (replacing unused NC) and supports up to 30 mA/string, requiring firmware validation if substituting in existing designs.