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Texas Instruments LM27952SDX/NOPB
- Part No.:
- LM27952SDX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LM27952SDX/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 30MA 14WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,243
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Product details
Overview
LM27952SDX/NOPB from Texas Instruments is a white LED adaptive 1.5X/1X switched-capacitor current driver IC, delivering up to 30 mA per channel across four tightly regulated current sinks with 0.2% typical matching, operating from 3.0 V to 5.5 V input, and optimized for display backlighting in portable devices.
For engineers reviewing the LM27952SDX/NOPB datasheet, LM27952SDX/NOPB pinout, LM27952SDX/NOPB application, or LM27952SDX/NOPB equivalent, key selection criteria include its 750 kHz fixed-frequency charge pump architecture, PWM-controlled brightness without charge-pump cycling, 14-pin WSON package thermal performance, and absence of inductors in the BOM.
Technical Context
The LM27952SDX/NOPB implements an adaptive gain-switching charge pump that dynamically selects between 1.5× and 1× modes based on LED forward voltage (2.5 V–3.9 V), maintaining peak efficiency (>85%) while minimizing input ripple via constant-frequency pre-regulation. Its internal 150 kΩ pull-down on EN simplifies enable logic.
It integrates four matched current sinks with headroom voltage as low as 240 mV at 21 mA, uses external RSET to program output current via ILED = 200 × (1.25 V / RSET), and supports independent PWM dimming without disabling the VOUT rail-enabling stable, low-noise LED control.
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 Channel | 30 mA - sufficient to drive four white LEDs at full brightness in small displays. |
| Current Matching Accuracy | 0.2% (typ.) - ensures uniform luminance across multi-LED arrays without optical compensation. |
| Switching Frequency | 750 kHz (±30%) - enables use of compact 1 µF ceramic flying capacitors and reduces EMI filtering burden. |
| Shutdown Current | <1 µA - preserves battery life during system sleep modes with EN pin low. |
| VOUT Headroom Requirement | 240 mV at 21 mA - allows operation with low-VF LEDs or stacked configurations near input rail. |
| Package Thermal Resistance θJA | 45 °C/W - enables sustained 4×30 mA operation with minimal PCB copper area when DAP is grounded. |
Pinout & Package
LM27952SDX/NOPB is housed in a 14-pin WSON package (4.0 mm × 3.0 mm × 0.8 mm, NHK0014A), featuring an exposed die-attach pad (DAP) soldered to PCB ground for enhanced thermal dissipation. The package is RoHS-compliant, lead-free (Sn finish), and MSL Level-1 rated.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (C2+) | Flying capacitor C2 positive terminal | Connects to one plate of 1 µF flying capacitor; forms half of 1.5× charge pump stage. |
| 2 (VOUT) | Pre-regulated charge pump output | Supplies all four current sinks; voltage adapts between ~3.0 V (1×) and ~4.5 V (1.5×) depending on load. |
| 3 (C1+) | Flying capacitor C1 positive terminal | Connects to one plate of second 1 µF flying capacitor; completes dual-capacitor charge pump topology. |
| 4–7 (D4–D1) | Regulated current sink inputs | Four independent LED cathode connections; each sinks programmed current with <0.2% matching. |
| 8 (ISET) | Current set reference node | Internal 1.25 V reference; RSET to GND sets all four LED currents via ILED = 200 × (1.25 V / RSET). |
| 9 (EN) | Enable logic input | Active-high; internal 150 kΩ pull-down ensures safe shutdown if left floating; <0.4 V = OFF, >1.0 V = ON. |
| 10 (PWM) | Brightness control logic input | Directly modulates current sinks without toggling charge pump; supports 100 Hz–1 kHz PWM for flicker-free dimming. |
| 11 (VIN) | Main power input | Accepts 3.0–5.5 V; powers internal circuitry and charge pump; requires 3.3 µF input capacitor. |
| 12 (C2−) | Flying capacitor C2 negative terminal | Completes C2 loop; ties to GND during charge phase and to VOUT during transfer phase. |
| 13 (GND) | Power supply ground | Primary return path; must be connected to DAP for optimal thermal and electrical performance. |
| 14 (C1−) | Flying capacitor C1 negative terminal | Completes C1 loop; switches between VIN and GND to generate boosted voltage at VOUT. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive 1.5×/1× gain switching | Maintains highest efficiency across input voltage range by selecting optimal charge pump mode based on real-time LED VF. |
| No-inductor architecture | Reduces solution size and cost using only four MLCCs (1 µF ×2, 3.3 µF ×2); eliminates EMI concerns and coil procurement. |
| Independent PWM dimming | Enables brightness control without cycling EN-preserving VOUT stability and minimizing input current spikes and noise. |
| Tightly matched current sinks | 0.2% typical matching ensures consistent LED luminance across channels, critical for uniform backlighting in displays. |
| Low-headroom current regulation | 240 mV headroom at 21 mA allows operation with low-VF LEDs or high-efficiency phosphor-converted types near VIN. |
Applications
| Smartphone Display Backlight | Tablet Keypad Illumination |
|---|---|
|
Use Scenario: Driving four parallel white LEDs behind a 4.7-inch OLED display requiring uniform brightness at 20 mA per LED. IC Role / Device Role / Timing Role: Adaptive switched-capacitor current driver regulating LED current and dynamically selecting 1× or 1.5× gain to maintain efficiency as battery voltage drops from 4.2 V to 3.3 V. Use Value: Eliminates need for inductor-based boost converter, reducing PCB area by >30% and enabling thinner bezel designs. |
Use Scenario: Illuminating tactile keypad buttons on an industrial handheld with ambient light sensing and dynamic brightness scaling. IC Role / Device Role / Timing Role: Four-channel current sink providing independent PWM dimming per button group while maintaining constant current under varying temperature and VF drift. Use Value: Achieves ±0.5% brightness consistency across 10,000-hour lifetime without recalibration or feedback sensors. |
| Portable Medical Monitor Backlight | Wearable Device Status Indication |
|
Use Scenario: Powering edge-lit LCD backlight in a Class II medical device where EMI compliance and reliability are critical. IC Role / Device Role / Timing Role: Low-noise, fixed-frequency charge pump delivering stable 25 mA per channel with <1 µA shutdown current during standby. Use Value: Meets CISPR-22 Class B conducted emissions limits without ferrite beads or shielding due to clean 750 kHz spectrum. |
Use Scenario: Driving two high-brightness indicator LEDs in a hearable device powered by a 3.7 V coin cell with 120-day runtime target. IC Role / Device Role / Timing Role: Dual-channel current source (D1+D2 paralleled) delivering 30 mA total with programmable RSET and ultra-low quiescent draw. Use Value: Extends battery life by 22% versus linear LED drivers due to >85% peak efficiency and sub-µA shutdown state. |
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 | Inductor-based boost converter with integrated FET; 1.2 MHz switching; supports up to 40 mA per channel. | Requires external inductor and diode; higher EMI; larger footprint but wider input range (2.7 V–6.5 V). | Choose when higher output voltage (>5.5 V) or higher per-channel current (>30 mA) is required. |
| MAX16832AATA+ | Linear LED driver with thermal foldback; 4-channel, 30 mA max; no switching noise. | Lower efficiency (<50% at 3.6 V input); limited to low-VF LEDs; no adaptive gain or PWM dimming flexibility. | Choose only for ultra-low-noise, low-power indicator applications where efficiency is secondary. |
Compared with TPS61165DRVR and MAX16832AATA+, the LM27952SDX/NOPB uniquely delivers inductor-free operation with adaptive gain, enabling smaller size and lower EMI than boost solutions while maintaining high efficiency across battery discharge-unlike linear alternatives that waste power as heat.
Availability
LM27952SDX/NOPB is available at Aetrix Electronics and suitable for smartphone display backlights, portable medical monitors, industrial keypad illumination, and wearable status indicators requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM27952SDX/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 technologies, with decades of leadership in precision analog IC design and high-volume manufacturing.
The LM27952SDX/NOPB belongs to TI's white LED driver product line, engineered specifically for space-constrained portable displays and user-interface lighting where inductor elimination, efficiency over battery voltage range, and luminance uniformity are primary design goals.
FAQ
What is the maximum number of LEDs the LM27952SDX/NOPB can drive simultaneously?
The LM27952SDX/NOPB can drive up to four white LEDs simultaneously-one per current sink (D1–D4)-each at up to 30 mA. It also supports paralleling outputs (e.g., D1+D2) to drive fewer LEDs at higher current, such as 60 mA through a single LED, provided headroom and thermal limits are observed. The LM27952SDX/NOPB does not support series-connected LEDs.
How does the LM27952SDX/NOPB achieve adaptive gain switching between 1.5× and 1× modes?
The LM27952SDX/NOPB monitors the voltage at the VDX node (internal to the current sinks) to detect LED forward voltage requirements. When VDX falls below 450 mV, it triggers transition from 1.5× to 1× gain to avoid unnecessary voltage boosting-maximizing efficiency. This decision is made autonomously by internal circuitry; no external control is needed. The LM27952SDX/NOPB performs this adaptation continuously during operation.
Can the LM27952SDX/NOPB operate with input voltages below 3.0 V?
No-the LM27952SDX/NOPB has a specified minimum input voltage of 3.0 V per its Absolute Maximum Ratings and Operating Ratings. Operation below 3.0 V may result in failure to regulate current, unstable VOUT, or complete shutdown. For sub-3.0 V applications, alternative drivers such as the TPS6106x family should be evaluated. The LM27952SDX/NOPB is not characterized or guaranteed for operation outside 3.0 V–5.5 V.
What is the role of the ISET pin on the LM27952SDX/NOPB, and how is LED current calculated?
The ISET pin on the LM27952SDX/NOPB provides a 1.25 V internal reference voltage. Connecting an external resistor RSET from ISET to GND sets the LED current according to ILED = 200 × (1.25 V / RSET). For example, a 12.5 kΩ resistor yields 20 mA per channel. The LM27952SDX/NOPB uses this single resistor to program all four channels identically, ensuring matched output without trimming.
Does the LM27952SDX/NOPB require special PCB layout considerations for thermal performance?
Yes-the LM27952SDX/NOPB uses a WSON package with an exposed die-attach pad (DAP) that must be soldered to a thermally robust PCB ground plane. TI recommends a 1:1 copper land matching the DAP size (3.0 mm × 1.6 mm) with multiple thermal vias to inner ground layers. Failure to connect the DAP degrades θJA from 45 °C/W to >100 °C/W, risking thermal shutdown under full 4×30 mA load. The LM27952SDX/NOPB thermal performance is directly dependent on this layout practice.
LM27952SDX/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)
LM27952SDX/NOPB FAQ
1.How can I place an order for LM27952SDX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM27952SDX/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 LM27952SDX/NOPB reliable?
The price and inventory of LM27952SDX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM27952SDX/NOPB is usually 5 days.
3.What payment methods are accepted for LM27952SDX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM27952SDX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM27952SDX/NOPB?
LM27952SDX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM27952SDX/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 LM27952SDX/NOPB?
For technical support, including LM27952SDX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM27952SDX/NOPB requirements.
6.How does Aetrix verify that LM27952SDX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM27952SDX/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 LM27952SDX/NOPB meets industry standards.
7.What is the process for return or replacement of LM27952SDX/NOPB?
All LM27952SDX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM27952SDX/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 LM27952SDX/NOPB part is unused and in its original packaging.
Return procedure for LM27952SDX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM27952SDX/NOPB Tags
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