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Texas Instruments LM27952SD/NOPB
- Part No.:
- LM27952SD/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LM27952SD/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 30MA 14WSON
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM27952SD/NOPB from Texas Instruments is a switched-capacitor white LED current driver IC with adaptive 1.5×/1× gain charge pump architecture, delivering up to 30 mA per channel across four tightly matched current sinks (±0.2% typical matching), operating from 3.0 V to 5.5 V input, and optimized for display backlighting in portable electronics.
For engineers reviewing the LM27952SD/NOPB datasheet, LM27952SD/NOPB pinout, LM27952SD/NOPB application, or LM27952SD/NOPB equivalent, key selection criteria include regulated current sink headroom (240–360 mV), fixed 750 kHz switching frequency, <1 µA shutdown current, WSON-14 package thermal resistance (45 °C/W), and PWM-controlled brightness without charge-pump cycling.
Technical Context
The LM27952SD/NOPB implements constant-frequency pre-regulation using a CMOS-based adaptive charge pump that dynamically selects between 1.5× and 1× gain modes based on LED forward voltage (2.5 V–3.9 V) and input supply (3.0 V–5.5 V), maximizing efficiency (>85% peak) while minimizing conducted EMI. Its internal reference fixes ISET pin voltage at 1.25 V (typ.), enabling precise LED current programming via external RSET.
Four independent current sinks (D1–D4) operate as low-headroom NMOS sinks with voltage compliance down to 240 mV at 21 mA, each controlled by dedicated logic-level inputs (EN for global enable, PWM for per-cycle modulation). The device integrates soft-start (330 µs typical startup), thermal shutdown (150 °C trip), and no-inductor operation enabled by four external ceramic capacitors (1 µF and 3.3 µF).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.0 V to 5.5 V - supports single-cell Li-ion and USB-powered systems without LDO pre-regulation. |
| Max Output Current per Sink | 30 mA - enables driving four standard white LEDs at full brightness with margin. |
| Current Matching Accuracy | ±0.2% (typ.) - ensures uniform display backlight luminance across all channels. |
| Switching Frequency | 750 kHz (±30%) - balances EMI suppression, capacitor size, and efficiency in portable designs. |
| Shutdown Current | <1 µA - preserves battery life during system sleep states. |
| Headroom Voltage (VHR) | 240–360 mV - defines minimum voltage drop across current sink for regulation at 21–31 mA. |
| Thermal Resistance θJA | 45 °C/W - requires minimal PCB copper area for thermal management in WSON-14 package. |
Pinout & Package
LM27952SD/NOPB is housed in a 14-pin WSON (No-Pullback Leadless Leadframe) package measuring 4.0 mm × 3.0 mm × 0.8 mm, featuring an exposed die-attach pad (DAP) soldered to PCB ground for enhanced thermal conduction (θJA = 45 °C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (C2+) | Flying capacitor C2 positive terminal | Connects to one plate of 1 µF flying capacitor used in 1.5× charge pump stage. |
| 2 (VOUT) | Pre-regulated charge pump output | Supplies bias to all four current sinks; voltage varies with gain mode (1× or 1.5×) and load. |
| 3 (C1+) | Flying capacitor C1 positive terminal | Connects to one plate of second 1 µF flying capacitor in dual-stage charge pump topology. |
| 4–7 (D4–D1) | Regulated current sink inputs | Each sinks programmed LED current (up to 30 mA); connected to cathodes of white LEDs. |
| 8 (ISET) | Current set reference node | Internal 1.25 V reference; RSET to GND sets LED current via IDx = 200 × (1.25 V / RSET). |
| 9 (EN) | Global enable logic input | Active-high (VIH ≥ 1.0 V); internal 150 kΩ pull-down ensures safe default-off state. |
| 10 (PWM) | Brightness control logic input | Modulates current sinks ON/OFF without disabling charge pump - reduces input ripple vs. EN PWM. |
| 11 (VIN) | Main power input | Accepts 3.0–5.5 V supply; powers internal circuitry and charge pump input stage. |
| 12 (C2−) | Flying capacitor C2 negative terminal | Completes C2 connection; tied to GND or VOUT depending on gain mode timing phase. |
| 13 (GND) | Power and signal ground | Reference for all voltages; must be low-impedance connection to DAP and system ground plane. |
| 14 (C1−) | Flying capacitor C1 negative terminal | Completes C1 connection; switches between GND and VOUT under charge pump control. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive 1.5×/1× charge pump | Automatically transitions gain based on LED VF and VIN to sustain >85% peak efficiency across input range. |
| Four matched current sinks | 0.2% typical current matching ensures consistent LED brightness without external calibration. |
| PWM brightness control (dedicated pin) | Enables flicker-free dimming (100–1000 Hz) without cycling charge pump - eliminates input current spikes. |
| No-inductor architecture | Reduces solution size and EMI risk using only four low-ESR MLCCs (1 µF and 3.3 µF). |
| Low-headroom current regulation | 240 mV headroom at 21 mA allows operation with low-VF LEDs or high-VIN conditions without dropout. |
Applications
| Smartphone Display Backlight | Tablet LCD Backlight |
|---|---|
|
Use Scenario: Driving four parallel white LEDs behind a 4.7″–7″ TFT-LCD panel in battery-powered smartphones. IC Role / Device Role / Timing Role: Adaptive charge pump current driver regulating 20–30 mA per LED with PWM dimming synchronized to display frame rate. Use Value: Eliminates inductor-related EMI and board space; maintains uniform brightness despite battery voltage sag from 4.2 V to 3.3 V. |
Use Scenario: Powering eight LEDs (two banks of four) in a 10″ tablet display with dynamic local dimming zones. IC Role / Device Role / Timing Role: Dual-channel current source controller using parallel D1–D4 outputs per bank, modulated via PWM for zone-specific luminance. Use Value: Enables compact, low-profile backlight solution with <1 µA shutdown current extending standby time. |
| Wearable OLED Keypad Backlight | Industrial HMI Panel Lighting |
|
Use Scenario: Illuminating segmented keypad LEDs in compact wearables where height and EMI are critical constraints. IC Role / Device Role / Timing Role: Low-noise current sink providing 10–15 mA per LED with 500 Hz PWM dimming and fast 330 µs startup. Use Value: Meets stringent thickness requirements (<0.8 mm profile) and avoids magnetic coupling into nearby sensors. |
Use Scenario: Driving indicator and status LEDs in industrial HMIs operating continuously at 85 °C ambient. IC Role / Device Role / Timing Role: Thermally robust current regulator with internal shutdown at 150 °C junction temperature and 45 °C/W θJA. Use Value: Ensures long-term reliability without derating in sealed enclosures; supports wide VIN (3.0–5.5 V) for varied power rails. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED current driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61165DRVR | Boost converter architecture (inductor-based); higher peak efficiency (>90%) but larger solution size and EMI sensitivity. | Requires external inductor and diode; better suited for higher LED VF (>4.0 V) or lower input (<3.0 V) than LM27952SD/NOPB. | Select when VF exceeds 3.9 V or when input may dip below 3.0 V; avoid if board space or EMI is constrained. |
| MAX1910ETE+ | Fixed 1.5× charge pump; no adaptive gain switching; 20 mA max per sink; 12-pin TQFN package. | Lacks 1× gain mode and PWM pin - brightness control requires EN pin toggling, increasing input ripple. | Choose for cost-sensitive, lower-current (≤20 mA) applications where adaptive efficiency is not required. |
Compared with TPS61165DRVR and MAX1910ETE+, the LM27952SD/NOPB uniquely combines inductorless operation, adaptive gain, dedicated PWM control, and sub-0.3% current matching - making it optimal for compact, low-EMI, multi-LED portable displays requiring stable luminance over battery discharge.
Availability
LM27952SD/NOPB is available at Aetrix Electronics and suitable for smartphone display backlights, tablet LCD modules, wearable keypad illumination, and industrial HMI lighting requiring stable component supply, long-lifecycle support, and RoHS-compliant WSON packaging.
Supply support for LM27952SD/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 U.S.-based semiconductor company specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and high-reliability interface solutions.
The LM27952SD/NOPB belongs to TI's white LED driver product line, engineered specifically for ultra-compact, high-efficiency backlighting in portable consumer electronics where inductor elimination and tight current matching are critical design requirements.
FAQ
What is the maximum number of white LEDs the LM27952SD/NOPB can drive simultaneously?
The LM27952SD/NOPB can drive up to four white LEDs simultaneously - one per current sink (D1–D4) - with each sink delivering up to 30 mA. Parallel connection of multiple sinks (e.g., D1+D2) enables higher per-LED current (e.g., 60 mA), but total power dissipation and thermal limits must be verified per application. The LM27952SD/NOPB datasheet confirms this capability under "Maximum Output Current" and "Parallel DX Outputs" sections.
Does the LM27952SD/NOPB require an external inductor?
No, the LM27952SD/NOPB uses a switched-capacitor (charge pump) architecture and requires only four external ceramic capacitors - two 1 µF flying capacitors (C1, C2) and two 3.3 µF bulk capacitors (CIN, COUT). This eliminates inductor-related EMI, size, and cost, distinguishing it from inductive boost LED drivers like the TPS61165DRVR. The absence of an inductor is explicitly stated in the "FEATURES" section of the LM27952SD/NOPB datasheet.
How is LED current programmed on the LM27952SD/NOPB?
LED current is programmed by connecting an external resistor (RSET) between the ISET pin (Pin 8) and GND. The internal amplifier holds ISET at 1.25 V (typ.), so current per sink equals IDx = 200 × (1.25 V / RSET). For example, a 12.5 kΩ resistor sets 20 mA per sink. This relationship is validated in the Electrical Characteristics table and APPLICATION INFORMATION section of the LM27952SD/NOPB datasheet.
What is the purpose of the dedicated PWM pin on the LM27952SD/NOPB?
Pin 10 (PWM) provides dedicated brightness control by modulating the four current sinks ON/OFF without disabling the charge pump - preserving VOUT stability and minimizing input current spikes. Unlike toggling the EN pin, PWM pin operation avoids repeated charge-pump startup transients, reducing input ripple and EMI. This behavior is documented in the "ENABLE AND PWM PINS" and "ADJUSTING LED BRIGHTNESS" sections of the LM27952SD/NOPB datasheet.
What thermal considerations apply to the LM27952SD/NOPB in continuous operation?
The LM27952SD/NOPB features thermal shutdown at 150 °C (typ.) and recovers at 140 °C (typ.). Its WSON-14 package has θJA = 45 °C/W, requiring adequate PCB copper area connected to the exposed DAP for heat dissipation. In high-power configurations (e.g., 30 mA × 4 LEDs at low VIN), junction temperature must stay ≤115 °C - achievable via thermal vias to inner ground planes. These parameters are specified in the Thermal Characteristics and POWER DISSIPATION sections of the LM27952SD/NOPB datasheet.
LM27952SD/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Switched Capacitor (Charge Pump)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 4
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 2.5V ~ 3.9V
- Current - Output / Channel:
- 30mA
- Frequency:
- 750kHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-WSON (4x3)
LM27952SD/NOPB FAQ
1.How can I place an order for LM27952SD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM27952SD/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 LM27952SD/NOPB reliable?
The price and inventory of LM27952SD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM27952SD/NOPB is usually 5 days.
3.What payment methods are accepted for LM27952SD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM27952SD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM27952SD/NOPB?
LM27952SD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM27952SD/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 LM27952SD/NOPB?
For technical support, including LM27952SD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM27952SD/NOPB requirements.
6.How does Aetrix verify that LM27952SD/NOPB is sourced from the original manufacturer or authorized distributors?
All LM27952SD/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 LM27952SD/NOPB meets industry standards.
7.What is the process for return or replacement of LM27952SD/NOPB?
All LM27952SD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM27952SD/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 LM27952SD/NOPB part is unused and in its original packaging.
Return procedure for LM27952SD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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