My Inquiry
My Account
Texas Instruments LM2791LD-L
- Part No.:
- LM2791LD-L
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LM2791LD-L.pdf
- Description:
- IC LED DRVR RGLTR ANALOG 10WSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,677
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2791LD-L from Texas Instruments is a current-regulated switched-capacitor LED driver IC designed to drive two white or blue LEDs with matched output currents (±0.3%) from 3V–5.8V input, delivering up to 36mA total (18mA per channel), featuring analog brightness control via BRGT pin and active-high shutdown. It targets compact backlight systems in portable Li-ion-powered devices.
For engineers reviewing the LM2791LD-L datasheet, LM2791LD-L pinout, LM2791LD-L application, or LM2791LD-L equivalent, key selection considerations include its WSON-10 package footprint, ±0.3% current matching tolerance, 450kHz minimum switching frequency, soft-start behavior, and analog dimming range (0–3V on BRGT).
Technical Context
The LM2791LD-L integrates a CMOS charge-pump voltage doubler with linear current regulation, using an internal 25:1 current mirror architecture referenced to an external RSET resistor to set LED current. Its analog brightness control applies a 0–3V voltage to the BRGT pin, which modulates the reference offset (200mV) via a 0.42× scaling factor before feeding the current mirror control amplifier.
It operates with active-high shutdown logic (SD pin tied to VIN enables operation), delivers regulated current without series resistors in the LED path, and includes thermal shutdown at 150°C with automatic recovery below 100°C. The 450kHz minimum switching frequency places conducted noise outside sensitive RF bands in handheld devices.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.0V to 5.8V - supports single-cell Li-ion battery operation across full discharge curve. |
| Max Output Current | 36mA total (18mA per LED) - sufficient for two medium-brightness white LEDs in backlight applications. |
| Current Matching | ±0.3% - ensures balanced luminance between dual LEDs without binning or calibration. |
| Switching Frequency | ≥450kHz - keeps switching harmonics above audio band and away from cellular RF front-end bands. |
| Shutdown Current | ≤1µA - enables ultra-low-power standby in battery-critical portable systems. |
| Operating Current | 0.7mA typical - minimizes quiescent load on small Li-ion cells during active backlight operation. |
| Brightness Control | Analog (0–3V on BRGT) - provides smooth, flicker-free dimming without PWM timing constraints or EMI spikes. |
Pinout & Package
LM2791LD-L is housed in a 10-pin WSON (NGY) package measuring 3mm × 3mm × 0.8mm with exposed thermal pad (2.0mm × 1.2mm), optimized for low θJA (55°C/W) and compact PCB layout in space-constrained portable designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (BRGT) | Analog brightness control input | Voltage (0–3V) sets LED current via internal 0.42× scaled reference; grounding fixes max current per RSET. |
| 2 (POUT) | Charge-pump output node | Provides doubled voltage rail for LED anodes; requires Schottky diode (e.g., BAT54) from VIN to POUT at startup. |
| 3 (C1−) | Flying capacitor negative terminal | Connects to negative side of 1µF ceramic flying capacitor (C1); low-ESR X5R/X7R required. |
| 4 (C1+) | Flying capacitor positive terminal | Connects to positive side of C1; forms charge-transfer path for voltage doubling stage. |
| 5 (D2), 6 (D1) | Matched current source outputs | Direct LED cathode connections; each delivers identical current (±0.3%) set by RSET and BRGT. |
| 7 (GND) | Power ground reference | System return path; must be connected to thermal pad for optimal thermal performance. |
| 8 (VIN) | Main supply input | 3V–5.8V Li-ion source; powers internal regulator, oscillator, and charge pump. |
| 9 (SD) | Active-high shutdown input | Logic high (≥0.8×VIN) enables device; logic low disables with ≤1µA quiescent draw. |
| 10 (ISET) | Current sense reference node | Connects external RSET to GND; sets mirror current (ILED = 25 × VREF/RSET, VREF ≈ 200mV). |
Key Features
| Feature | Design Value |
|---|---|
| No-inductor architecture | Eliminates magnetic components and EMI concerns-enables <3mm × 3mm solution size with only ceramic capacitors. |
| Matched dual current sources | ±0.3% matching over temperature and line ensures uniform display backlight intensity without optical compensation. |
| Soft-start circuitry | Ramps internal bandgap reference to limit inrush current during power-up, preventing voltage droop on shared Li-ion rails. |
| Linear regulation noise profile | Generates predictable, non-random noise spectrum-simplifies EMI filtering vs. switching regulators in RF-sensitive layouts. |
| Thermal protection | Shuts down charge pump at 150°C junction temperature and recovers automatically below 100°C-prevents permanent damage under sustained overload. |
Applications
| White LED Display Backlights | White LED Keypad Backlights |
|---|---|
Use Scenario: Driving dual white LEDs behind segmented LCD displays in PDAs or handheld PCs. IC Role / Device Role / Timing Role: Constant-current LED driver with matched outputs ensuring uniform brightness across display segments. Use Value: Eliminates need for discrete current-setting resistors and binning, reducing BOM count and assembly cost while maintaining visual consistency. | Use Scenario: Illuminating alphanumeric keypads in cellular phones powered by 3.7V Li-ion batteries. IC Role / Device Role / Timing Role: Analog-dimmable dual-channel current source enabling user-adjustable keypad brightness without PWM flicker. Use Value: 0–3V BRGT control allows direct interface to MCU DAC or potentiometer, simplifying firmware and eliminating PWM timer resource usage. |
| 1-Cell Li-Ion Portable Devices | Flat Panel Displays |
Use Scenario: Powering backlights in compact medical handhelds or barcode scanners operating from single-cell Li-ion (3.0–4.2V). IC Role / Device Role / Timing Role: Input-voltage-tolerant LED driver maintaining stable current despite battery voltage sag during discharge. Use Value: 3.0V–5.8V input range covers full Li-ion operational envelope, avoiding premature backlight dimming or dropout near end-of-discharge. | Use Scenario: Edge-lit backlighting for small-format TFT panels in industrial HMIs or test equipment. IC Role / Device Role / Timing Role: Dual-channel current regulator driving parallel LED strings for even illumination across narrow bezels. Use Value: D1/D2 outputs can be paralleled to drive single higher-current LED (e.g., 30mA), retaining ±0.3% matching and analog dimming capability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2792LD-L | Same pinout and function but with active-low shutdown (SD pin active low); otherwise identical electrical specs and package. | Requires inverted logic control signal; not drop-in compatible without level-shifting or firmware change. | Select LM2792LD-L only when system-level shutdown signaling is active-low and board layout cannot accommodate logic inversion. |
| TPS61160DRVR | Boost-based LED driver with 1.2MHz switching, 30mA per channel, no analog dimming-uses PWM-only brightness control. | Lacks analog dimming; higher-frequency operation increases EMI risk near RF sections; requires inductor. | Choose TPS61160DRVR only if higher efficiency at low input voltages (<3.3V) or tighter output voltage regulation is prioritized over analog dimming and inductor-free design. |
Compared with LM2791LD-L, LM2792LD-L offers identical performance with reversed shutdown polarity-requiring logic adaptation but no layout change-while TPS61160DRVR trades analog dimming and inductorless simplicity for higher boost efficiency and different noise characteristics.
Availability
LM2791LD-L is available at Aetrix Electronics and suitable for white LED display backlights, keypad illumination, and 1-cell Li-ion portable equipment requiring stable component supply and legacy design support.
Supply support for LM2791LD-L 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies with broad industrial and consumer reach.
The LM2791 product line delivers compact, inductorless LED drivers for portable backlighting, emphasizing current matching, analog dimming, and Li-ion compatibility-designed specifically for space- and power-constrained handheld displays.
FAQ
What is the shutdown logic polarity of LM2791LD-L?
The LM2791LD-L uses active-high shutdown: applying a logic high signal (≥0.8×VIN) to the SD pin enables normal operation, while pulling SD low disables the device and reduces quiescent current to ≤1µA. This differs from the LM2792LD-L variant, which uses active-low shutdown. Always verify SD pin voltage thresholds against actual VIN in your design.
How does the BRGT pin control LED brightness in LM2791LD-L?
The BRGT pin accepts an analog voltage from 0V to 3.0V to linearly adjust LED current: 0V yields maximum current (set by RSET), and increasing BRGT voltage reduces current per the formula ILED = (((BRGT × 0.42) + 0.20)/RSET) × 25. This enables flicker-free dimming without PWM circuitry-critical for sensitive optical or EMI environments where LM2791LD-L is deployed.
Can LM2791LD-L drive a single LED at higher current?
Yes-LM2791LD-L supports parallel connection of D1 and D2 outputs to drive one LED at up to 36mA. To do so, configure RSET and BRGT such that each channel delivers half the target current (e.g., 15mA per channel for 30mA total). Internal current matching (±0.3%) ensures balanced contribution, and all electrical specifications-including voltage compliance and thermal limits-remain valid in this configuration.
What capacitor types are required for stable LM2791LD-L operation?
LM2791LD-L requires low-ESR ceramic capacitors: CIN, C1, C2, and CHOLD must be X5R or X7R dielectrics rated ≥6.3V with ESR ≤0.3Ω. Recommended values are 1µF for CIN, C1, and CHOLD. Using higher-ESR or electrolytic capacitors degrades output regulation, reduces efficiency, and may cause instability-verified in TI's SNVS156M datasheet test conditions for LM2791LD-L.
Is LM2791LD-L suitable for new designs?
No-TI classifies LM2791LD-L as "Not Recommended For New Designs" (NRND) per its packaging addendum. While still available for legacy support and existing production, Aetrix Electronics advises evaluating modern alternatives like TPS61160DRVR or LP5569 for new projects due to improved efficiency, integrated diagnostics, and active product lifecycle status. LM2791LD-L remains fully supported for continuity in fielded systems.
LM2791LD-L Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Switched Capacitor (Charge Pump)
- Internal Switch(s):
- -
- Number of Outputs:
- 2
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 5.8V
- Voltage - Output:
- -
- Current - Output / Channel:
- 36mA
- Frequency:
- 650kHz
- Dimming:
- Analog
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-WSON (3x3)
LM2791LD-L FAQ
1.How can I place an order for LM2791LD-L through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2791LD-L 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 LM2791LD-L reliable?
The price and inventory of LM2791LD-L are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2791LD-L is usually 5 days.
3.What payment methods are accepted for LM2791LD-L?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2791LD-L transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2791LD-L?
LM2791LD-L orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2791LD-L 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 LM2791LD-L?
For technical support, including LM2791LD-L datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2791LD-L requirements.
6.How does Aetrix verify that LM2791LD-L is sourced from the original manufacturer or authorized distributors?
All LM2791LD-L 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 LM2791LD-L meets industry standards.
7.What is the process for return or replacement of LM2791LD-L?
All LM2791LD-L units undergo pre-shipment inspection (PSI). If there is an issue with LM2791LD-L, 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 LM2791LD-L part is unused and in its original packaging.
Return procedure for LM2791LD-L:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2791LD-L Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
