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Texas Instruments LM27965SQ
- Part No.:
- LM27965SQ
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM27965SQ.pdf
- Description:
- IC LED DRV RGLTR I2C 30MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,431
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Product details
Overview
LM27965SQ from Texas Instruments is a dual-display white LED driver IC with I²C-compatible brightness control, adaptive 1×/3/2× charge pump, 180mA total output current, 0.3% current matching across banks, and 91% peak efficiency. It drives up to 9 LEDs in three independently controlled banks (5+3+1) for main display, sub-display, and indicator lighting in space-constrained portable devices.
For engineers reviewing the LM27965SQ datasheet, LM27965SQ pinout, LM27965SQ application, or LM27965SQ equivalent, this page delivers verified technical context on charge-pump gain selection, I²C register mapping (0x36 address), RSET-based current programming (IDxx = 200 × 1.25V / RSET), headroom voltage requirements (VHR = 110mV @ 15mA), and thermal derating guidance for WQFN-24 (RTW0024A) layout.
Technical Context
The LM27965SQ implements an adaptive CMOS charge pump that dynamically switches between 1× pass-through and 3/2× boost modes based on real-time forward voltage monitoring of active DxA/DxB pins - transition occurs at VDxx ≈ 175mV to maintain regulation headroom. Gain selection is fully autonomous and requires no external control.
It integrates three independent current-sink banks: BankA (D1A–D5A, 5 pins), BankB (D1B–D3B, 3 pins), and BankC (D1C, 1 pin), each with distinct brightness control schemes - 32-level PWM+analog for Banks A/B, and 4-level analog-only for BankC. All banks share the same RSET-programmed full-scale current (up to 30mA per sink).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 5.5V - supports single-cell Li-ion battery operation without external LDO |
| Total Output Current | 180mA max - distributed across three banks; enables simultaneous main/sub/indicator backlighting |
| LED Current Matching | 0.3% typical - ensures uniform brightness across all 9 LEDs under varying temperature and supply conditions |
| Charge Pump Efficiency | 91% peak - achieved via adaptive gain switching; eliminates need for inductor and reduces EMI |
| I²C Address | 0x36 (7-bit) - fixed hardware address; enables multi-device bus configuration with LM27965SQ-M (0x38) |
| Switching Frequency | 1.27MHz typical - high-frequency operation minimizes required flying capacitor size (1µF) |
| Headroom Voltage | 110mV @ 15mA - defines minimum (VPOUT − VLED) margin required for stable current regulation |
Pinout & Package
LM27965SQ is housed in a 24-pin WQFN package (RTW0024A), 4mm × 4mm × 0.8mm, with exposed thermal pad (DAP) connected to GND for enhanced thermal dissipation (θJA = 41.3°C/W). Pin pitch is 0.5mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (24) | Power input | Accepts 2.7–5.5V; supplies charge pump and internal circuitry |
| POUT (23) | Charge pump output | Regulated output node (4.6V typ. in closed-loop); connects to LED anodes |
| C1 (19,22), C2 (20,21) | Flying capacitors | Two 1µF ceramic caps enable 3/2× boost; no inductor required |
| D1A–D5A (12–16) | BankA current sinks | 5 independent sinks for main display LEDs; support parallel connection |
| D1B–D3B (4–6) | BankB current sinks | 3 sinks for sub-display; forward-voltage sensing enables gain optimization |
| D1C (3) | BankC current sink | Single sink for indicator LED; no voltage sensing; 4-level analog dimming |
| ISET (17) | Current reference | 1.25V reference node; RSET to GND sets full-scale current (IDxx = 200 × 1.25V / RSET) |
| SCL (1), SDIO (2) | I²C interface | Standard bidirectional I²C bus; compatible with 1.4–VIN logic levels (VIO referenced) |
| VIO (7) | I/O voltage reference | Sets logic threshold for SCL/SDIO; decouples interface voltage from VIN |
| RESET (10) | Hardware reset | Active-low; forces all registers to default state and disables outputs when pulled low |
| GND (9,18,DAP) | Ground return | Three dedicated GND pins + exposed DAP ensure low-impedance return path and thermal conduction |
| NC (8,11) | No connect | Unbonded pins; must remain unconnected per TI design |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive 1×/3/2× charge pump | Automatically selects gain mode based on real-time LED forward voltage to maximize efficiency across input range |
| Three independent LED banks | BankA (5 sinks), BankB (3 sinks), BankC (1 sink) - enables differentiated brightness control for main, sub, and indicator displays |
| 0.3% current matching | Guarantees consistent LED brightness across all 9 channels without external calibration or trimming |
| I²C-compatible interface (0x36) | Supports standard 400kHz I²C timing; enables software-controlled dimming, bank enable/disable, and register readback |
| Resistor-programmable full-scale current | RSET value directly determines maximum per-sink current (e.g., 12.7kΩ → 20mA; 8.33kΩ → 30mA) |
| Thermal shutdown protection | Engages at TJ ≈ 170°C and releases at 165°C - prevents permanent damage during overload or poor PCB thermal design |
Applications
| Mobile Phone Main Display Backlight | PDA Dual-Screen Lighting |
|---|---|
Use Scenario: Driving 5 white LEDs (3.6V VF) for primary LCD backlight in compact smartphone form factor with Li-ion battery supply (3.0–4.2V). IC Role / Device Role / Timing Role: Constant-current LED driver with adaptive charge-pump gain selection and I²C brightness control. Use Value: Eliminates inductor, reduces solution size to 25mm², and maintains >90% efficiency across battery discharge curve via automatic 1×→3/2× transition at VDxA ≈ 175mV. |
Use Scenario: Simultaneous illumination of main (5-LED) and secondary (3-LED) displays in handheld PDA, with independent brightness scaling. IC Role / Device Role / Timing Role: Dual-bank LED driver with separate PWM/analog dimming control per bank and shared RSET current setting. Use Value: Enables synchronized UI transitions (e.g., dim sub-display while brightening main) using two independent I²C registers (0xA0 and 0xB0) without additional ICs. |
| Indicator LED Driver in Wearables | Compact Consumer Electronics Lighting |
Use Scenario: Driving single status LED (e.g., power-on indicator) in ultra-thin wearable device where board area and BOM count are critical. IC Role / Device Role / Timing Role: Dedicated BankC current sink (D1C) with 4-level analog dimming and no sensing overhead. Use Value: Replaces discrete LED driver + resistor network; saves 2.5mm² PCB area and provides calibrated 20%/40%/70%/100% brightness levels via register 0xC0. |
Use Scenario: Backlighting small-format displays (e.g., smart remote, IoT panel) requiring <180mA total drive with minimal external components. IC Role / Device Role / Timing Role: Integrated charge-pump LED driver with integrated current sinks, flying caps, and I²C interface. Use Value: Reduces bill-of-materials to only 4 external capacitors (CIN, COUT, C1, C2) and one RSET resistor - no inductors, MOSFETs, or op-amps required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-display LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM27964SQ | Same WQFN-24 package and pinout; lacks BankC (D1C) sink and RESET pin; only two LED banks (5+3) | Cannot drive indicator LED independently; no hardware reset functionality | Select when indicator lighting is unnecessary and system-level reset is handled externally |
| TPS61165DRVR | Boost converter topology (inductor-based); 40V output capability; single 30mA channel; no multi-bank I²C control | Requires external inductor and diode; supports higher-VF LEDs but lacks dual-display segmentation | Select when driving high-VF LEDs (>4.0V) or when board area allows inductor placement |
Compared with LM27965SQ, LM27964SQ removes BankC and RESET but retains identical BankA/B performance and pin compatibility, whereas TPS61165DRVR trades charge-pump simplicity for higher output voltage flexibility at the cost of added magnetics and reduced integration.
Availability
LM27965SQ is available at Aetrix Electronics and suitable for mobile phone display lighting, PDA dual-screen backlighting, and compact consumer electronics requiring stable component supply, long-term lifecycle support, and RoHS-compliant WQFN packaging.
Supply support for LM27965SQ 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 interface solutions.
The LM27965SQ belongs to TI's white LED driver product line, engineered specifically for space-constrained portable devices needing efficient, multi-bank, I²C-controllable backlighting without inductors.
FAQ
What is the I²C address of the LM27965SQ and how is it configured?
The LM27965SQ has a fixed 7-bit I²C slave address of 0x36 (binary 0110110), hardwired internally and not configurable via pins or registers. This address is used during the START condition to select the device for write/read operations. The LM27965SQ-M variant uses 0x38. No external pull-up resistors are required on SCL/SDIO beyond standard I²C bus design; however, the pull-up to VIO must exceed (VIO − 0.4V)/3mA to meet VOL specification. The LM27965SQ responds to standard I²C timing including repeated STARTs and 9-bit acknowledge cycles.
How is LED current set on the LM27965SQ and what is the role of RSET?
LED current on the LM27965SQ is set by connecting an external resistor (RSET) between the ISET pin and GND. The internal ISET pin is regulated to 1.25V, so full-scale current per sink equals IDxx = 200 × (1.25V / RSET). For example, RSET = 12.7kΩ yields ~20mA per DxA/DxB/D1C sink. This relationship holds across all three banks and is temperature-stable due to matched internal current mirrors. RSET tolerance directly impacts absolute current accuracy, so 1% metal-film resistors are recommended for production designs using LM27965SQ.
Does the LM27965SQ require external flying capacitors, and what are their specifications?
Yes, the LM27965SQ requires two external 1.0µF low-ESR ceramic flying capacitors (C1 and C2) connected to pins 19/22 and 20/21 respectively. TI specifies X5R or X7R dielectrics with ≤100mΩ ESR, such as TDK C1608X5R1A105K. These capacitors enable the adaptive 3/2× charge pump operation and must be placed within 2mm of the IC with short, wide traces to minimize loop inductance. Omitting or undersizing C1/C2 causes unstable POUT voltage, excessive ripple, and potential current regulation failure in LM27965SQ operation.
What thermal considerations apply to the LM27965SQ in high-current operation?
The LM27965SQ has a junction-to-ambient thermal resistance (θJA) of 41.3°C/W in the RTW0024A WQFN package. At 180mA total load with 3.6V input and 3.6V LED VF, power dissipation reaches ~180mW - raising junction temperature by ~7.4°C above ambient. To maintain TJ < 100°C (operating limit), ambient must stay below 92.6°C with standard layout. For sustained 180mA operation, TI recommends connecting the exposed DAP pad to a ≥40mm² internal GND plane via ≥4 thermal vias (0.3mm diameter) to reduce θJA by up to 15°C/W. Thermal shutdown activates at TJ ≈ 170°C as a safety backup.
Can the LM27965SQ drive LEDs with forward voltages above 4.0V?
No - the LM27965SQ is specified for LED forward voltages from 2.0V to 4.0V per the Absolute Maximum Ratings table. Attempting to drive >4.0V LEDs risks violating the IDxx pin voltage limit of (VPOUT + 0.3V) ≤ 6.0V, since maximum POUT in 3/2× mode is ~1.5 × 5.5V = 8.25V, but internal clamping and regulation prevent stable operation beyond 4.0V VF. For higher-VF applications (e.g., blue/green LEDs or series strings), TI recommends boost-based alternatives like TPS61165. The LM27965SQ's charge pump architecture is optimized for standard white LEDs (3.0–3.6V VF) in portable devices.
LM27965SQ 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:
- 9
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 2V ~ 4V
- Current - Output / Channel:
- 30mA
- Frequency:
- 1.27MHz
- Dimming:
- I2C
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x4)
LM27965SQ FAQ
1.How can I place an order for LM27965SQ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM27965SQ 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 LM27965SQ reliable?
The price and inventory of LM27965SQ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM27965SQ is usually 5 days.
3.What payment methods are accepted for LM27965SQ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM27965SQ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM27965SQ?
LM27965SQ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM27965SQ 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 LM27965SQ?
For technical support, including LM27965SQ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM27965SQ requirements.
6.How does Aetrix verify that LM27965SQ is sourced from the original manufacturer or authorized distributors?
All LM27965SQ 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 LM27965SQ meets industry standards.
7.What is the process for return or replacement of LM27965SQ?
All LM27965SQ units undergo pre-shipment inspection (PSI). If there is an issue with LM27965SQ, 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 LM27965SQ part is unused and in its original packaging.
Return procedure for LM27965SQ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM27965SQ Tags
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BCR420UE6433HTMA1
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