Texas Instruments LM27965SQ-MX/NOPB

Overview

LM27965SQ-MX/NOPB from Texas Instruments is a charge-pump-based dual-display white LED driver IC with I²C-compatible brightness control. It delivers up to 180mA total output current across three independently controlled banks (BankA: up to 5 LEDs, BankB: up to 3 LEDs, BankC: 1 indicator LED), supports 2.7V–5.5V input, achieves 91% peak efficiency, and maintains 0.3% current matching between LEDs in same bank - used in mobile phone main/sub display backlighting.

For engineers reviewing the LM27965SQ-MX/NOPB datasheet, LM27965SQ-MX/NOPB pinout, LM27965SQ-MX/NOPB application, or LM27965SQ-MX/NOPB equivalent, key selection criteria include adaptive 1×/3/2× charge-pump gain switching, resistor-programmable full-scale current (via RSET), hardware RESET pin, WQFN-24 package thermal performance (θ_JA = 41.3°C/W), and I²C address 0x36 compatibility.

Technical Context

The LM27965SQ-MX/NOPB implements an adaptive CMOS charge pump that dynamically selects 1× (pass-mode) or 3/2× gain based on real-time forward voltage monitoring of active Dxx pins in BankA and BankB - ensuring optimal efficiency across input voltage (2.7V–5.5V) and LED V_F (2.0V–4.0V) ranges. Gain transition occurs at ~175mV headroom threshold to prevent current sink pinch-off.

It integrates three regulated current-sink banks: BankA (D1A–D5A, 5 pins), BankB (D1B–D3B, 3 pins), and BankC (D1C, 1 pin), each with independent enable and brightness control. BankA/B support 32-level I²C-controlled dimming (mix of analog scaling + 20kHz PWM); BankC offers 4-level analog-only dimming. All banks share one RSET/ISET current programming network (ID_xx = 200 × 1.25V / RSET).

Key Specifications

Pinout & Package

LM27965SQ-MX/NOPB uses a 24-pin WQFN package (4mm × 4mm × 0.8mm, RTW0024A), featuring an exposed thermal pad (DAP) connected to GND for enhanced heat transfer. Pin count and layout match TI's standard LM27965 family footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM27964SQ/NOPB, LM27965SQ-MX/NOPB adds dedicated indicator control and hardware RESET for safety-critical UIs; versus TPS61165DRVR, it eliminates inductor EMI and enables precise digital brightness scheduling via I²C registers.

Availability

LM27965SQ-MX/NOPB is available at Aetrix Electronics and suitable for mobile phone display lighting, PDA dual-screen backlighting, and portable medical device status indicators requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM27965SQ-MX/NOPB 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 specializing in analog, embedded processing, and power management ICs, with decades of expertise in precision power conversion and display interface solutions.

The LM27965 product line targets compact, battery-powered consumer and portable medical devices requiring highly integrated, efficient, and digitally controllable LED backlighting - emphasizing minimal external components and thermal reliability.

FAQ

What is the I²C address of the LM27965SQ-MX/NOPB?

The LM27965SQ-MX/NOPB has a fixed 7-bit I²C slave address of 0x36 (binary 0110110). This distinguishes it from the LM27965-M variant (0x38). The address is hardwired and cannot be changed via pins or registers. Communication requires standard I²C start condition, address byte with R/W bit, register address byte (e.g., 0xA0 for BankA brightness), and data byte. The LM27965SQ-MX/NOPB acknowledges each byte with SDIO pulled low during the 9th clock pulse.

How is LED current set for the LM27965SQ-MX/NOPB?

LED current for all banks (BankA, BankB, BankC) of the LM27965SQ-MX/NOPB is set by an external resistor RSET connected between the ISET pin (Pin 17) and GND. The relationship is ID_xx = 200 × (1.25V / RSET), where 1.25V is the internally regulated ISET pin voltage. For example, a 12.7kΩ RSET yields ~20mA per Dxx pin. This single resistor configures full-scale current for all 9 outputs, ensuring matched scaling across banks without individual trimming.

Does the LM27965SQ-MX/NOPB require an inductor?

No, the LM27965SQ-MX/NOPB does not require an inductor. It uses an adaptive switched-capacitor (charge-pump) architecture with external flying capacitors C1 and C2 (1µF ceramic) to generate the boosted POUT voltage. This eliminates inductor-related EMI, size, cost, and layout sensitivity - making it ideal for space-constrained portable designs where magnetic components are undesirable or prohibited.

What is the purpose of the RESET pin on the LM27965SQ-MX/NOPB?

RESET (Pin 10) is an active-low hardware reset input for the LM27965SQ-MX/NOPB. When driven low, it asynchronously resets all internal registers (including brightness control and enable bits) to their power-on defaults and disables all LED drivers. This provides deterministic system-level recovery independent of I²C bus state - essential for fault handling, power sequencing, or forced reinitialization in safety-critical applications like medical devices.

Can BankA and BankB of the LM27965SQ-MX/NOPB be used simultaneously?

Yes, BankA (D1A–D5A) and BankB (D1B–D3B) of the LM27965SQ-MX/NOPB can be enabled and operated simultaneously. Each bank has independent enable bits (ENA/ENB in General Purpose Register 0x10) and brightness registers (0xA0/0xB0). When both are active, the charge pump monitors all enabled Dxx pins for gain control, and total output current remains within the 180mA limit - e.g., 125mA to BankA and 45mA to BankB. Current matching (0.3%) applies separately within each bank.