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Texas Instruments LM27964SQ-C/NOPB
- Part No.:
- LM27964SQ-C/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM27964SQ-C/NOPB.pdf
- Description:
- IC LED DRV RGLTR I2C 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,186
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Product details
Overview
LM27964SQ-C/NOPB from Texas Instruments is a charge-pump white LED driver IC optimized for dual-display mobile backlighting and keypad illumination. It delivers up to 30mA per LED across four Group A outputs (main LCD), 30mA per LED across two Group B outputs (sub LCD), and 80mA total to keypad LEDs, with I²C-compatible 23kHz PWM brightness control, 87% peak efficiency, and operation from 2.7V–5.5V input.
For engineers reviewing the LM27964SQ-C/NOPB datasheet, LM27964SQ-C/NOPB pinout, LM27964SQ-C/NOPB application, or LM27964SQ-C/NOPB equivalent, this page provides verified technical context, exact pin functions, real-world current matching performance (0.2% between sinks), adaptive 1×/3/2× charge pump behavior, and validated alternative options for display lighting designs.
Technical Context
The LM27964SQ-C/NOPB implements an adaptive CMOS charge pump that dynamically selects 1× (pass-through) or 3/2× gain based on real-time forward voltage monitoring of active Group A/B LED pins-transitioning at ~375mV headroom to maintain regulation without inductor use. Its internal reference fixes ISETx pin voltage at 1.25V, enabling precise external resistor programming of output currents.
It integrates three independent current-sink banks: Group A (D1A–D4A, 4×30mA max), Group B (D1B–D2B, 2×30mA max), and Keypad (DKEY, 80mA total), each with distinct dimming methods-16-step 23kHz PWM for Groups A/B, and 4-level analog scaling for DKEY-controlled via I²C address 0x36 with dedicated brightness registers at 0xA0h and 0xB0h.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 5.5V - supports full Li-ion battery range including discharge tail without dropout. |
| LED Output Current | Group A: 30mA per sink ×4; Group B: 30mA per sink ×2; DKEY: 80mA total - enables flexible multi-display + keypad lighting from single IC. |
| Current Matching | 0.2% typical between sinks in same bank - ensures uniform luminance across main/sub LCDs without per-LED calibration. |
| PWM Frequency | 23kHz (LM27964SQ-C variant) - eliminates audible noise and visible flicker in handheld displays. |
| Charge Pump Efficiency | 87% peak - achieved via adaptive gain selection and low ROUT (2.75Ω) minimizes thermal load in space-constrained phones. |
| I²C Interface | Standard-mode compatible (SCL ≤400kHz), address 0x36 - allows direct integration with baseband/application processors without level-shifting. |
| Package | WQFN-24 (4mm × 4mm × 0.8mm) with exposed DAP - provides low thermal resistance (θJA = 41.3°C/W) for sustained 180mA total output. |
Pinout & Package
LM27964SQ-C/NOPB uses the RTW0024A 24-pin WQFN package (4mm × 4mm × 0.8mm) with thermally enhanced exposed die attach pad (DAP). Pin numbering follows standard QFN top-view convention (pin 1 at top-left corner, counterclockwise).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (24) | Main power input | Accepts 2.7V–5.5V Li-ion supply; feeds charge pump and internal regulators. |
| POUT (23) | Charge pump regulated output | Provides adaptive 1× or 3/2× boosted voltage to LED anodes; monitored for gain control. |
| C1/C2 (19,20,21,22) | Flying capacitor connections | Supports charge transfer in 3/2× mode; requires 1.0µF X7R ceramic caps with low ESR. |
| D1A–D4A (13–16), D1B–D2B (4–5), DKEY (6) | LED cathode current sinks | Individually controlled constant-current outputs; Group A/B support PWM dimming, DKEY uses analog scaling. |
| ISETA/ISETB/ISETK (17,3,12) | Current reference inputs | Set full-scale current via external resistors: IDxx = 200×(1.25V/RSETA/B) or 800×(1.25V/RSETK). |
| SCL/SDIO/VIO (1,2,7) | I²C interface signals | Standard bidirectional bus: VIO defines logic levels (1.8V–VIN); SCL max 400kHz; address 0x36. |
| GND (9,10,18,DAP) | Ground reference | Multiple ground pins and exposed DAP ensure low-impedance return path and thermal dissipation. |
| NC (8,11) | No-connect | Not internally bonded; must be left floating or tied to GND per layout best practice. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive 1×/3/2× charge pump | Automatically switches gain based on real-time LED forward voltage sensing to maximize efficiency across input and load variations. |
| 0.2% current matching between sinks | Ensures consistent brightness across all LEDs in Group A or Group B without software compensation or binning. |
| 23kHz PWM dimming (Group A/B) | Eliminates audible coil whine and perceptible flicker in portable displays while maintaining smooth brightness transitions. |
| Dedicated keypad driver (DKEY) | Delivers up to 80mA with 4-level analog scaling (100%/70%/40%/20%)-optimized for low-current, high-count keypad LED arrays. |
| I²C register map with brightness control | Separate 8-bit registers at 0xA0h (Groups A/B) and 0xB0h (DKEY) enable independent, glitch-free dimming without reinitializing the bus. |
Applications
| Main LCD Backlighting | Sub LCD Backlighting |
|---|---|
|
Use Scenario: Illuminating high-resolution TFT main display in feature phones and early smartphones with tight power budgets. IC Role / Device Role / Timing Role: Constant-current sink driver for four parallel white LEDs; regulates current independently per channel using Group A outputs (D1A–D4A). Use Value: Delivers uniform 30mA per LED with 0.2% matching, eliminating visual banding and enabling 16-step 23kHz PWM for flicker-free user interface rendering. |
Use Scenario: Powering secondary monochrome or low-res LCD in clamshell or dual-screen devices. IC Role / Device Role / Timing Role: Independent constant-current sink for two white LEDs via Group B outputs (D1B–D2B), controlled separately from main display. Use Value: Enables simultaneous but differentiated brightness control of main and sub displays using shared I²C bus and discrete register addressing (0xA0h). |
| Keypad LED Lighting | Multi-Function Indicator Lighting |
|
Use Scenario: Driving 8–16 discrete keypad LEDs in mobile handsets requiring low-profile, low-noise illumination. IC Role / Device Role / Timing Role: Dedicated analog current-scaling driver (DKEY) with 4 fixed brightness levels and 80mA total output capacity. Use Value: Provides stable keypad illumination without PWM artifacts, supporting ballast resistors to mitigate LED Vf mismatch across multiple parallel strings. |
Use Scenario: General-purpose status lighting in portable medical or industrial handhelds where display and indicator share power rail. IC Role / Device Role / Timing Role: Flexible current sink resource-Group A/B outputs repurposed for non-display indicators; DKEY used for tactile feedback LEDs. Use Value: Single-chip solution reduces BOM count by consolidating main display, sub-display, and system indicator drivers into one WQFN-24 package. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM27965SQ/NOPB | Same architecture but fixed 10kHz PWM frequency (no -C/-I suffix variants); identical pinout and register map. | Lacks 23kHz option-may cause audible noise in sensitive acoustic environments or visible flicker in high-refresh-rate displays. | Select when 10kHz PWM is acceptable and legacy design reuse is prioritized over flicker/noise optimization. |
| TPS61165DRVR | Boost-based (inductor required), 1.2MHz switching, 30mA per channel ×6; no keypad-dedicated bank or analog dimming. | Requires external inductor and more board area; supports higher LED count but lacks integrated keypad driver functionality. | Choose for designs needing >6 LEDs or wider input range (1.8V–6.5V), accepting added component count and EMI considerations. |
Compared with LM27964SQ-C/NOPB, LM27965SQ/NOPB offers identical functionality except PWM frequency, while TPS61165DRVR trades integrated keypad control and charge-pump simplicity for greater LED count flexibility and lower input voltage support-requiring careful trade-off analysis per application constraints.
Availability
LM27964SQ-C/NOPB is available at Aetrix Electronics and suitable for mobile phone display lighting, PDA backlighting, and keypad LED applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for LM27964SQ-C/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 connectivity technologies, with decades of expertise in power management and display interface solutions.
The LM27964SQ-C/NOPB belongs to TI's white LED driver product line, engineered specifically for space-constrained, battery-powered mobile devices requiring efficient dual-display backlighting and integrated keypad illumination in a single compact IC.
FAQ
What is the PWM frequency of the LM27964SQ-C/NOPB?
The LM27964SQ-C/NOPB features a fixed 23kHz PWM frequency for Groups A and B LED outputs. This value is factory-trimmed and cannot be modified via register settings. The 23kHz frequency was selected to eliminate audible noise and visible flicker in handheld displays, distinguishing it from the 10kHz LM27964SQ-I/NOPB variant. The LM27964SQ-C/NOPB datasheet confirms this specification under Electrical Characteristics, fPWM parameter.
How do I set the LED current for Group A using the LM27964SQ-C/NOPB?
To set Group A LED current on the LM27964SQ-C/NOPB, connect a precision resistor (RSETA) between ISETA (pin 17) and GND. The output current per DxA pin equals 200 × (1.25V ÷ RSETA). For example, a 16.9kΩ resistor yields ~15mA per sink (30mA full-scale across two enabled sinks). RSETA must be placed close to the IC with short traces to minimize noise coupling into the reference node.
Does the LM27964SQ-C/NOPB support independent brightness control for main and sub displays?
Yes, the LM27964SQ-C/NOPB supports fully independent brightness control for main and sub displays via separate I²C-accessible registers. Group A (main LCD) brightness is controlled through bits DxA3–DxA0 in register 0xA0h, while Group B (sub LCD) uses DxB3–DxB0 in the same register. Each group offers 16 discrete PWM steps (1/16 to full scale), allowing simultaneous but differentiated dimming without interference.
What is the maximum total output current capability of the LM27964SQ-C/NOPB?
The LM27964SQ-C/NOPB supports a maximum total output current of 180mA, distributed across its three banks: up to 120mA for Group A (4 × 30mA), 60mA for Group B (2 × 30mA), and 80mA for DKEY. However, simultaneous full-scale operation of all banks exceeds 180mA; practical allocation must respect the 180mA ceiling-for example, 30mA × 4 (Group A) + 30mA × 2 (Group B) + 60mA (DKEY) = 180mA exactly.
Can the LM27964SQ-C/NOPB drive LEDs with forward voltage above 4.0V?
No-the LM27964SQ-C/NOPB specifies a maximum LED forward voltage of 4.0V per the Operating Ratings table. Attempting to drive LEDs with Vf > 4.0V risks violating the current sink headroom requirement (VHR = VPOUT − VLED ≥ 180mV), leading to loss of regulation and reduced brightness consistency. For higher-Vf LEDs, consider boost-based alternatives like TPS61165DRVR that support up to 28V output.
LM27964SQ-C/NOPB 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)
LM27964SQ-C/NOPB FAQ
1.How can I place an order for LM27964SQ-C/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM27964SQ-C/NOPB 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 LM27964SQ-C/NOPB reliable?
The price and inventory of LM27964SQ-C/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM27964SQ-C/NOPB is usually 5 days.
3.What payment methods are accepted for LM27964SQ-C/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM27964SQ-C/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM27964SQ-C/NOPB?
LM27964SQ-C/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM27964SQ-C/NOPB 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 LM27964SQ-C/NOPB?
For technical support, including LM27964SQ-C/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM27964SQ-C/NOPB requirements.
6.How does Aetrix verify that LM27964SQ-C/NOPB is sourced from the original manufacturer or authorized distributors?
All LM27964SQ-C/NOPB 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 LM27964SQ-C/NOPB meets industry standards.
7.What is the process for return or replacement of LM27964SQ-C/NOPB?
All LM27964SQ-C/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM27964SQ-C/NOPB, 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 LM27964SQ-C/NOPB part is unused and in its original packaging.
Return procedure for LM27964SQ-C/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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