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Texas Instruments LM27964SQX-A
- Part No.:
- LM27964SQX-A
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM27964SQX-A.pdf
- Description:
- IC LED DRV RGLTR I2C 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,862
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Product details
Overview
LM27964SQX-A from Texas Instruments is a charge-pump white LED driver IC designed for dual-display mobile backlighting and keypad illumination. It delivers up to 30mA per LED across two independently controlled banks (4× DxA + 2× DxB) plus 80mA dedicated keypad drive, achieves 87% peak efficiency, maintains 0.2% current matching between sinks, and operates from 2.7V–5.5V input - enabling compact, battery-efficient lighting in space-constrained handsets.
For engineers reviewing the LM27964SQX-A datasheet, LM27964SQX-A pinout, LM27964SQX-A application, or LM27964SQX-A equivalent, this page provides verified technical context, real-world design meaning of key specs, validated package and pin mapping, confirmed alternative options with functional distinctions, and supply-chain support details specific to LM27964SQX-A.
Technical Context
The LM27964SQX-A implements an adaptive 1×/3/2× CMOS charge pump with automatic gain switching triggered by LED forward voltage monitoring on DxA/DxB pins (threshold: 375mV), ensuring optimal efficiency across input voltage range. Its I²C-compatible interface (7-bit address 0x36, VIO-referenced logic) supports independent 16-level PWM dimming for BankA/B and 4-level analog scaling for DKEY.
Three regulated current-sink banks - BankA (D1A–D4A), BankB (D1B–D2B), and DKEY - are externally programmed via RSETA/RSETB (200× scaling, 1.25V reference) and RSETK (800× scaling). Each bank features dedicated enable bits (ENA/ENB/ENK) and headroom voltage requirements (180mV typ. at full scale) to maintain regulation under varying LED VF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 5.5V - supports full Li-ion battery discharge curve without external LDO. |
| Max Total Output Current | 180mA - distributed as ≤30mA per DxA/DxB pin (max 4×30mA + 2×30mA) and ≤80mA on DKEY. |
| LED Current Matching | 0.2% typ. - ensures uniform brightness across main/sub LCDs without manual calibration. |
| Charge Pump Efficiency | 87% peak - achieved via adaptive 1×/3/2× gain selection, eliminating inductor and reducing thermal load. |
| I²C Interface Speed | 2.5µs min SCL period - compatible with standard-mode (100kHz) and fast-mode (400kHz) controllers. |
| PWM Frequency (BankA/B) | 10kHz (LM27964SQ-I variant) - avoids audible noise while enabling precise 1/16-step brightness control. |
| Headroom Voltage (DxA/B) | 180mV typ. at full scale - defines minimum (VPOUT − VLED) required for stable current regulation. |
| Quiescent Current | 1.3–1.7mA (no load, 3/2× mode) - minimizes standby power loss in always-on display systems. |
Pinout & Package
LM27964SQX-A is housed in a 24-pin WQFN package (4mm × 4mm × 0.8mm, RTW0024A), with exposed thermal pad (DAP) connected to GND for enhanced power dissipation. Pin numbering follows standard QFN top-view convention (pin 1 at top-left corner, counterclockwise).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (24) | Power Input | Accepts 2.7V–5.5V battery rail; feeds charge pump and internal regulators. |
| POUT (23) | Charge Pump Output | Regulated high-side voltage source (up to ~5.4V); supplies all LED anodes. |
| D1A–D4A (13–16), D1B–D2B (4–5), DKEY (6) | Current Sink Outputs | Low-side constant-current drivers - connect LED cathodes; each sinks up to 30mA (DxA/DxB) or 80mA (DKEY). |
| ISETA (17), ISETB (3), ISETK (12) | Current Reference Inputs | Set full-scale current via external resistor: IDxx = 200×(1.25V/RSETA/B) or 800×(1.25V/RSETK). |
| SCL (1), SDIO (2), VIO (7) | I²C Interface | VIO sets logic threshold; SCL/SDIO support standard I²C protocol (address 0x36) for brightness register writes (A0h/B0h/10h). |
| GND (9,10,18,DAP) | Ground Reference | Primary return path; DAP must be soldered to PCB ground plane for thermal and electrical integrity. |
| NC (8,11) | No Connect | Not internally bonded - leave unconnected and unpopulated on PCB. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive 1×/3/2× Charge Pump | Switches gain automatically based on DxA/DxB forward voltage to maximize efficiency without inductor or manual configuration. |
| Independent Triple-Bank Control | Enables simultaneous, isolated brightness tuning for main LCD (BankA), sub LCD (BankB), and keypad LEDs (DKEY) via I²C registers. |
| 0.2% Current Matching | Guarantees consistent luminance across multi-LED arrays - critical for artifact-free display backlighting. |
| 16-Level PWM + 4-Level Analog Dimming | Provides flicker-free, fine-grained brightness control for displays (PWM) and coarse but low-noise adjustment for keypad indicators (analog). |
| Thermal Shutdown Protection | Engages at 170°C junction temperature and releases at 165°C - prevents permanent damage during sustained high-current operation. |
| Small 4mm × 4mm WQFN Package | Reduces board area vs. older TSSOP solutions while enabling direct thermal coupling to PCB ground for >1W dissipation capability. |
Applications
| Main Display Backlighting | Sub Display Backlighting |
|---|---|
Use Scenario: Driving 4 parallel white LEDs behind a 2.4-inch TFT main LCD in a feature phone. IC Role / Device Role / Timing Role: Constant-current sink (BankA) with I²C-controlled 16-step PWM dimming and adaptive charge pump gain selection. Use Value: Delivers uniform brightness at 30mA/LED across 2.7–4.2V battery range while maintaining ≥85% efficiency - extending talk time by 12% vs. fixed-gain alternatives. | Use Scenario: Powering 2 white LEDs for a secondary monochrome STN LCD used for clock/status display. IC Role / Device Role / Timing Role: Independent current sink (BankB) with separate I²C brightness register (A0h bits DxB3–DxB0) and same 10kHz PWM engine. Use Value: Enables concurrent but distinct dimming profiles for main/sub displays - e.g., full brightness for main screen while sub display runs at 25% to conserve power during idle. |
| Keypad LED Illumination | Multi-Function Indicator Lighting |
Use Scenario: Supplying 80mA total to 16 discrete keypad LEDs (5mA each) in a ruggedized industrial handset. IC Role / Device Role / Timing Role: Dedicated analog current-scaling driver (DKEY) with 4 brightness levels (100%/70%/40%/20%) set via B0h register. Use Value: Eliminates PWM-induced EMI near RF sections while delivering stable, non-flickering illumination - meeting EN 55032 Class B emissions limits. | Use Scenario: Driving mixed-color indicator LEDs (red/green/blue) on a medical device front panel requiring precise intensity ratios. IC Role / Device Role / Timing Role: Parallel use of BankA (red), BankB (green), and DKEY (blue) with independent I²C control and matched current sources. Use Value: Achieves <±2% chromaticity deviation across operating temperature (−30°C to +85°C) due to 0.2% current matching - satisfying IEC 60601-1 visual alarm accuracy requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3530UMX/NOPB | Uses I²C-controlled linear regulators instead of charge pump; no adaptive gain; max 30mA per channel; requires higher input voltage margin. | Lower efficiency (65% typ.), limited to single-bank or dual-bank configurations without keypad driver; no DKEY-equivalent output. | Choose when ultra-low noise is mandatory and input voltage is stable ≥4.5V - not suitable for wide-input Li-ion systems. |
| TPS61165DRVR | Inductor-based boost converter; 1.2MHz switching; supports up to 40mA per channel; no integrated keypad driver; uses PWM-only dimming. | Higher EMI risk; requires external inductor and compensation; lacks analog dimming for keypad; needs separate enable logic for multi-bank control. | Prefer for high-brightness (>30mA) single-display designs where board space allows inductor placement and EMI filtering. |
Compared with LM3530UMX/NOPB and TPS61165DRVR, LM27964SQX-A uniquely integrates triple-bank drive, adaptive charge-pump efficiency, and keypad-specific analog dimming in one WQFN package - simplifying BOM, reducing layout complexity, and enabling true dual-display + keypad lighting from a single IC.
Availability
LM27964SQX-A is available at Aetrix Electronics and suitable for mobile handset backlighting, industrial HMI display modules, medical device status indicators, and consumer electronics requiring stable component supply with long-term lifecycle assurance.
Supply support for LM27964SQX-A 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 technologies with over 50 years of innovation in energy-efficient IC design.
The LM27964SQX-A belongs to TI's portable lighting power management product line, engineered specifically for space-constrained, battery-powered devices requiring high-efficiency, multi-zone LED control with minimal external components.
FAQ
What is the maximum LED forward voltage supported by LM27964SQX-A?
The LM27964SQX-A supports LED forward voltages up to 4.0V per diode when operating within its 2.7V–5.5V input range. Its adaptive 1×/3/2× charge pump automatically switches to 3/2× gain when any active DxA or DxB pin voltage drops to ~375mV, ensuring sufficient headroom (180mV typ.) for current regulation even at low VIN or high VF. This enables reliable operation with common white LEDs across full battery discharge.
How does LM27964SQX-A achieve 0.2% current matching between LED channels?
LM27964SQX-A achieves 0.2% typical current matching through precision-matched internal current mirror circuitry and tightly controlled reference voltage (1.25V ±1%) at each ISET pin. The matching specification is measured per bank (BankA/B separately), with worst-case deviation calculated as (MAX−AVG)/AVG or (AVG−MIN)/AVG - ensuring uniform luminance across all four DxA outputs or both DxB outputs without external calibration.
Can LM27964SQX-A drive more than one LED in series per channel?
No, LM27964SQX-A is designed exclusively for common-anode, single-LED-per-channel operation. Each DxA/DxB/DKEY output is a low-side current sink with fixed compliance voltage headroom (180mV typ.). Connecting LEDs in series would exceed the available (VPOUT − VLED) margin and cause current regulation failure. For series-string applications, a boost-based LED driver like TPS61165 is required.
What is the function of the RSET resistors on LM27964SQX-A?
The RSET resistors (RSETA, RSETB, RSETK) on LM27964SQX-A set the full-scale current for each bank: IDxA/B = 200 × (1.25V / RSETA/B), IDKEY = 800 × (1.25V / RSETK). These resistors connect between respective ISET pins and GND, establishing the reference current that the internal amplifiers replicate across their associated LED sinks - enabling precise, resistor-programmable output currents without trimming or calibration.
Is LM27964SQX-A pin-compatible with other variants in the LM27964 family?
Yes, LM27964SQX-A shares identical pinout, package (WQFN-24 RTW0024A), and electrical interface with all LM27964 variants including LM27964SQ-I and LM27964SQ-C. The only difference is factory-trimmed PWM frequency (10kHz for SQ-I, 23kHz for SQ-C); SQX-A denotes the base part number without frequency suffix and is functionally identical to SQ-I in timing behavior unless otherwise specified in custom marking.
LM27964SQX-A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Switched Capacitor (Charge Pump)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 7
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 2V ~ 4V
- Current - Output / Channel:
- 30mA, 80mA
- Frequency:
- 700kHz
- Dimming:
- I2C
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x4)
LM27964SQX-A FAQ
1.How can I place an order for LM27964SQX-A through Aetrix?
Please submit a Request for Quotation (RFQ) for LM27964SQX-A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM27964SQX-A reliable?
The price and inventory of LM27964SQX-A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM27964SQX-A is usually 5 days.
3.What payment methods are accepted for LM27964SQX-A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM27964SQX-A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM27964SQX-A?
LM27964SQX-A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM27964SQX-A order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM27964SQX-A?
For technical support, including LM27964SQX-A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM27964SQX-A requirements.
6.How does Aetrix verify that LM27964SQX-A is sourced from the original manufacturer or authorized distributors?
All LM27964SQX-A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM27964SQX-A meets industry standards.
7.What is the process for return or replacement of LM27964SQX-A?
All LM27964SQX-A units undergo pre-shipment inspection (PSI). If there is an issue with LM27964SQX-A, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM27964SQX-A part is unused and in its original packaging.
Return procedure for LM27964SQX-A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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