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Texas Instruments LM2796TLX/NOPB
- Part No.:
- LM2796TLX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 18-WFBGA
- Datasheet:
-
LM2796TLX/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 18DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:1,949
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Product details
Overview
LM2796TLX/NOPB from Texas Instruments is a dual-group white LED driver IC with integrated 3/2× switched-capacitor boost converter, delivering up to 20 mA per LED across seven regulated current outputs (4+3), operating from 2.7V–5.5V input, and optimized for mobile phone main/sub-display backlighting.
For engineers reviewing the LM2796TLX/NOPB datasheet, LM2796TLX/NOPB pinout, LM2796TLX/NOPB application, or LM2796TLX/NOPB equivalent, key selection considerations include independent PWM dimming per LED group, 1.5× charge pump gain below 4.75V VIN, 18-bump DSBGA package (2.1 mm × 2.4 mm), ISET-based current programming (100× ratio), and thermal shutdown at 160°C.
Technical Context
The LM2796TLX/NOPB implements a dual-mode charge pump: 1.5× gain when VIN ≤4.75 V (enabling white LED drive from depleted Li-ion cells), and 1× pass-through above that threshold to minimize power loss. Its POUT pin delivers unregulated boosted voltage, while internal current mirrors-biased from POUT and trimmed for matching-feed seven discrete current-sink outputs.
Three logic-controlled enable inputs govern operation: EN (master shutdown), ENA (Group A: D1A–D4A), and ENB (Group B: D1B–D3B), each with 300 kΩ internal pull-downs. LED current is set via external RSET connected to ISET, where IDxx = 100 × (1.25 V / RSET), and soft-start limits inrush with ~100 µs turn-on time.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 5.5 V - supports full Li-ion battery discharge curve without external regulation. |
| LED Output Current | Up to 20 mA per channel - programmable via RSET; 15 mA typical with 8.35 kΩ resistor. |
| Charge Pump Gain | 3/2× (1.5×) below 4.75 V VIN; 1× above - dynamically optimizes efficiency across battery voltage range. |
| Current Matching | ±1% between outputs in same group - ensures uniform display brightness without external calibration. |
| Switching Frequency | 325–675 kHz - fixed-frequency operation enables predictable EMI filtering and capacitor sizing. |
| Thermal Shutdown | Triggers at TJ ≈160°C, recovers at ≈120°C - protects against sustained overloads in compact handheld layouts. |
| PWM Dimming Range | 100 Hz to 1 kHz - avoids visible flicker while preventing interference with internal current control loop. |
Pinout & Package
LM2796TLX/NOPB uses an 18-bump thin DSBGA package (YZR0018), measuring 2.1 mm × 2.4 mm × 0.6 mm, with 0.4 mm pitch and solder-ball terminations. It requires controlled thermal and mechanical mounting per TI Application Note SNVA009.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power Input | Supplies charge pump and bias circuitry; accepts 2.7–5.5 V Li-ion source directly. |
| GND | Ground Reference | Common return for all current sinks, charge pump, and logic; must be low-impedance plane. |
| POUT | Charge Pump Output | Unregulated output node (~1.5×VIN or VIN); feeds all current-sink high-side drivers. |
| C1+, C1−, C2+, C2− | Flying Capacitor Terminals | Interface external 1 µF ceramic capacitors to implement 3/2× charge pump topology. |
| EN | Master Enable | Active-high logic input; pulls down internally (300 kΩ); shuts down entire IC when low. |
| ENA, ENB | Group Enable Inputs | Independent active-high controls for Group A (4 LEDs) and Group B (3 LEDs); support PWM dimming. |
| D1A–D4A, D1B–D3B | LED Current Sinks | Seven regulated current-output terminals; sink up to 20 mA each to GND-connected LEDs. |
| ISET | Current Programming Node | Reference point for external RSET; maintains 1.25 V, enabling precise LED current scaling (IDxx = 100 × 1.25 V/RSET). |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent LED groups | 4-channel Group A and 3-channel Group B allow separate brightness control for main + sub-displays or keypad lighting. |
| Efficiency-optimized charge pump | Auto-switches between 1.5× and 1× gain based on VIN, reducing quiescent current to 3.5 mA (typ.) and shutdown current to 4.5 µA. |
| Matched current sources | ±1% matching within each group ensures <1% luminance variation across all 7 LEDs under identical conditions. |
| Integrated soft-start | ~100 µs controlled ramp prevents input voltage droop and inrush spikes during enable transitions. |
| Thermal protection | Internal shutdown at 160°C junction temperature prevents damage during sustained high-current or poor PCB thermal design. |
Applications
| Mobile Phone Main Display Backlight | Mobile Phone Sub-Display Backlight |
|---|---|
Use Scenario: Driving four white LEDs behind a primary LCD panel in a GSM/UMTS smartphone with single-cell Li-ion supply. IC Role / Device Role / Timing Role: Constant-current LED driver with 1.5× charge pump boosting VIN (as low as 3.0 V) to ~4.5 V for LED forward voltage compliance. Use Value: Enables full brightness at end-of-battery life without requiring external DC/DC converter or higher-voltage battery. |
Use Scenario: Powering three white LEDs for secondary display (e.g., flip-phone cover screen or status indicator). IC Role / Device Role / Timing Role: Independent current-sink group with dedicated ENB enable and PWM dimming capability. Use Value: Allows asynchronous dimming and on/off control of sub-display without affecting main display brightness or efficiency. |
| Mobile Phone Keypad Lighting | Handheld PDA Display Backlight |
Use Scenario: Illuminating alphanumeric keypad LEDs using spare outputs from Group B or time-multiplexed Group A channels. IC Role / Device Role / Timing Role: Low-noise current sink with logic-level enable; driven by baseband processor GPIOs. Use Value: Eliminates need for discrete current-limiting resistors and reduces BOM count versus discrete FET+resistor solutions. |
Use Scenario: Backlighting QVGA or VGA monochrome/color LCD in industrial or consumer PDAs powered by 3.7 V Li-ion. IC Role / Device Role / Timing Role: High-efficiency switched-capacitor LED driver supporting wide input range and ambient temperature operation (–30°C to +85°C). Use Value: Maintains consistent backlight intensity across temperature extremes and battery discharge cycles without recalibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3530TMX/NOPB | Uses I²C interface for digital current/brightness control; lacks independent group enables; requires external MCU communication. | Best suited for systems needing dynamic brightness adjustment via firmware rather than hardware PWM signals. | Select when system already includes I²C infrastructure and requires fine-grained per-LED current tuning beyond simple group dimming. |
| TPS61160DRVR | Inductor-based boost converter; higher peak efficiency (>90%) but larger solution size; single-group 5-output architecture. | Preferred for applications demanding maximum efficiency at high LED currents (>25 mA) or where EMI constraints favor spread-spectrum switching. | Choose when board space allows inductor placement and efficiency outweighs footprint/cost advantages of capacitor-based topology. |
Compared with LM3530TMX/NOPB and TPS61160DRVR, the LM2796TLX/NOPB offers hardware-native dual-group PWM dimming without MCU overhead or inductor-related layout complexity, making it optimal for cost-sensitive, space-constrained mobile handsets requiring robust analog control.
Availability
LM2796TLX/NOPB is available at Aetrix Electronics and suitable for mobile phone display lighting, keypad illumination, and PDA backlighting requiring stable component supply, long-term production continuity, and RoHS-compliant packaging.
Supply support for LM2796TLX/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 experience in portable power and display interface solutions.
The LM2796TLX/NOPB belongs to TI's white LED driver product line, engineered specifically for ultra-compact, high-efficiency backlighting in battery-powered handheld devices with dual-display architectures.
FAQ
What is the recommended capacitor value for CIN and CPOUT in the LM2796TLX/NOPB?
The LM2796TLX/NOPB datasheet specifies 1 µF ceramic capacitors for CIN and CPOUT under standard operation. However, if total LED current exceeds 80 mA-such as when all seven outputs operate simultaneously at ≥20 mA-the design recommends upgrading to 2.2 µF capacitors for both CIN and CPOUT to maintain stability and reduce ripple. These must be low-ESR X5R or X7R MLCCs rated for ≥10 V.
How does the LM2796TLX/NOPB handle input voltage transitions across the 4.75 V threshold?
The LM2796TLX/NOPB automatically switches between 3/2× and 1× charge pump modes near 4.75 V: gain drops from 1.5× to 1× as VIN rises above ~4.55 V (1x-to-1.5x threshold), and reverts when VIN falls below ~4.75 V (1.5x-to-1x threshold). This hysteresis prevents oscillation during slow battery discharge. No external control is needed-the transition is fully internal and seamless to downstream circuitry.
Can the LM2796TLX/NOPB drive LEDs with forward voltages exceeding 4.0 V?
Yes, but only when VIN is sufficiently high to sustain required headroom. For example, with VIN = 5.5 V and 1.5× gain disabled (1× mode), POUT ≈5.5 V, allowing up to ~5.2 V LED forward voltage assuming 22 mV/mA headroom. At lower VIN (e.g., 3.0 V), POUT ≈4.5 V in 1.5× mode, limiting usable VF to ~4.0 V max. Designers must verify (1.5×VIN − VF) > (N × ILED × ROUT) + (ILED × 22 mV/mA) for reliability.
What is the function of the ISET pin on the LM2796TLX/NOPB, and how is LED current calculated?
The ISET pin on the LM2796TLX/NOPB serves as the reference node for external current-setting resistor RSET. An internal amplifier holds ISET at 1.25 V (typ.), so current through RSET equals 1.25 V / RSET. The LM2796TLX/NOPB scales this by 100× to set all seven LED output currents: IDxx = 100 × (1.25 V / RSET). For 15 mA per LED, RSET = 8.35 kΩ; for 10 mA, RSET = 12.5 kΩ.
Does the LM2796TLX/NOPB require external compensation components?
No, the LM2796TLX/NOPB is fully internally compensated. Its charge pump and current regulation loops do not require external capacitors, resistors, or feedback networks. Stability is ensured across the full operating range (2.7 V–5.5 V input, –30°C to +85°C ambient) using only the four specified external ceramic capacitors (CIN, C1, C2, CPOUT) and RSET. This simplifies layout and eliminates tuning effort.
LM2796TLX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 18-WFBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- -
- Current - Output / Channel:
- 20mA
- Frequency:
- 500kHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 18-DSBGA
LM2796TLX/NOPB FAQ
1.How can I place an order for LM2796TLX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2796TLX/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 LM2796TLX/NOPB reliable?
The price and inventory of LM2796TLX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2796TLX/NOPB is usually 5 days.
3.What payment methods are accepted for LM2796TLX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2796TLX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2796TLX/NOPB?
LM2796TLX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2796TLX/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 LM2796TLX/NOPB?
For technical support, including LM2796TLX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2796TLX/NOPB requirements.
6.How does Aetrix verify that LM2796TLX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2796TLX/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 LM2796TLX/NOPB meets industry standards.
7.What is the process for return or replacement of LM2796TLX/NOPB?
All LM2796TLX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2796TLX/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 LM2796TLX/NOPB part is unused and in its original packaging.
Return procedure for LM2796TLX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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