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Texas Instruments LM2755TMX/NOPB
- Part No.:
- LM2755TMX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 18-WFBGA
- Datasheet:
-
LM2755TMX/NOPB.pdf
- Description:
- IC LED DRV RGLTR I2C 18DSBGA
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM2755TMX/NOPB from Texas Instruments is a charge-pump-based constant-current LED driver IC for trapezoidal dimming of three independent LEDs, delivering up to 30mA per channel (90mA total), operating from 2.7V–5.5V input, achieving 90% peak efficiency with no inductor required, and used in keypad and display backlighting.
For engineers reviewing the LM2755TMX/NOPB datasheet, LM2755TMX/NOPB pinout, LM2755TMX/NOPB application, or LM2755TMX/NOPB equivalent, key selection factors include I²C-compatible brightness control with 32 exponential steps, programmable trapezoidal waveform timing per channel, adaptive 1×/3/2× charge pump gain switching, and hardware enable/reset functionality.
Technical Context
The LM2755TMX/NOPB integrates an adaptive charge pump with automatic gain selection (1× or 3/2×) based on real-time LED forward voltage monitoring at each IDx pin, ensuring optimal efficiency across input voltage and load variations. It uses internal current sinks with 200× ISET-to-IDx current ratio and 1% typical output current matching between channels.
Timing control is implemented via 8-bit registers for rise/fall/high/low/delay parameters per channel, synchronized either to an internal 1.25MHz oscillator or an external clock up to 1MHz applied to SYNC, with step resolution down to 50µs (NSTEP=0) or scalable via 2NSTEP scaling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 5.5V - supports single-cell Li-ion, Li-polymer, and 3.3V/5V rail operation without level-shifting. |
| Max Total Output Current | 90mA - split across three independently controlled channels (≤30mA each) with thermal derating above +85°C ambient. |
| Charge Pump Gain Modes | 1× (pass-through) and 3/2× - automatically selected based on VDx headroom; transition threshold at ~350mV on active Dx pins. |
| I²C Interface | Standard-mode compatible (≤400kHz) with dual selectable addresses (0x18 or 0x67 via ADDR pin) - enables multi-device bus configuration. |
| Dimming Resolution | 32 exponential brightness steps (800:1 dimming ratio) - matches human eye luminance perception, avoiding visible nonlinearity in low-brightness regions. |
| Quiescent Current | 1.3mA typical (VIN=3.6V) - enables low-power standby in always-on UI applications without disabling system power rails. |
| Shutdown Current | 9.5µA max - achieved via HWEN pin low or I²C register disable; preserves battery life during deep sleep modes. |
Pinout & Package
Tiny 18-bump thin DSBGA package (YFQ0018AAA), 1.8mm × 1.6mm × 0.6mm, 0.4mm pitch, bottom-side solder balls.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1, A3, A5 (ID1–ID3) | LED cathode current sink outputs | Each drives one LED string with programmable trapezoidal dimming; requires external anode connection to POUT or regulated supply. |
| B2 (ISET) | Current set reference input | Sets full-scale LED current via external resistor (e.g., 12.5kΩ → 20mA/channel); internal 1.25V reference enables precise scaling. |
| B4 (HWEN) | Hardware enable/reset input | Active-high logic control: low = immediate reset to default register state and shutdown; bypasses I²C for fast system-level power sequencing. |
| B6 (SDIO) | I²C bidirectional data line | Open-drain interface referenced to VIO; requires external pull-up to VIO (not VIN) for proper logic level translation and VOL compliance. |
| C1 (VIN) | Main power input | Supplies charge pump and internal circuitry; decoupled by CIN (1µF ceramic) placed near pin to minimize noise and inrush transients. |
| C3, D6 (GND) | Ground terminals | Dual GND balls reduce ground impedance and improve current-sink matching; must be connected to low-impedance PCB ground plane. |
| C5 (VIO) | I²C logic voltage reference | Sets SCL/SDIO logic thresholds; can be tied to 1.8V, 2.5V, or 3.3V rail independent of VIN - enables mixed-voltage system interfacing. |
| C7 (SCL) | I²C clock input | Drives internal timing generator; frequency determines register access speed but does not affect PWM or dimming timing unless CLK bit enabled. |
| D2 (POUT) | Charge pump regulated output | Provides boosted voltage (up to ~1.5×VIN) to LED anodes; requires COUT (1µF) for stability and ripple suppression. |
| D4, E1, E3, E5 (C2−, C1+, C2+, C1−) | Flying capacitor connections | Four terminals for two 0.47µF ceramic flying caps (C1, C2); layout symmetry critical for charge transfer efficiency and EMI reduction. |
| E7 (ADDR) | I²C address select | High = 0x67, low = 0x18 - allows two LM2755TMX/NOPB devices on same I²C bus without address conflict or software arbitration. |
| A7 (SYNC) | External clock synchronization input | Accepts 1MHz max square wave to drive PWM and timing registers; divides by 32 internally to generate 31.25kHz base frequency. |
Key Features
| Feature | Design Value |
|---|---|
| No-inductor charge pump architecture | Eliminates magnetic components and associated EMI; achieves <13mm² total solution size using only four 0402 MLCCs. |
| Per-channel trapezoidal dimming control | Independent rise/fall/high/low/delay programming per LED enables custom blink patterns, breathing effects, and smooth transitions without MCU intervention. |
| Adaptive gain selection with VDx monitoring | Monitors headroom on active IDx pins only; switches to 3/2× mode only when needed - maximizes efficiency across varying LED VF and battery discharge profiles. |
| Hardware enable with fast reset | HWEN pin forces immediate register reset and shutdown within microseconds - critical for fail-safe UI shutdown during system fault conditions. |
| Exponential 32-step brightness mapping | Maps register values 0–31 to current levels using (0.9)(31−n) scaling - delivers perceptually uniform dimming steps across full range. |
Applications
| Keypad Backlighting | Display Backlighting |
|---|---|
Use Scenario: Illuminating membrane or capacitive keypads in portable medical devices and industrial HMIs where uniform low-current illumination is required. IC Role / Device Role / Timing Role: LM2755TMX/NOPB acts as standalone current-regulated LED driver with programmable fade-in/fade-out timing per key group. Use Value: Enables soft-touch visual feedback with zero MCU GPIO overhead and consistent brightness across temperature (-30°C to +85°C). |
Use Scenario: Driving edge-lit or direct-lit white LED arrays behind small TFT displays in handheld test equipment and wearables. IC Role / Device Role / Timing Role: LM2755TMX/NOPB serves as compact, high-efficiency backlight controller with independent channel dimming for local contrast enhancement. Use Value: Delivers 90% peak efficiency at 3.6V input and 3.4V LED VF, extending battery runtime while maintaining tight current matching (<1%) between channels. |
| Indicator Lighting | Fun-light Effects |
Use Scenario: Status indication in USB-C accessories, smart plugs, and IoT gateways requiring multicolor or blinking status signals. IC Role / Device Role / Timing Role: LM2755TMX/NOPB functions as autonomous LED sequencer using internal registers to generate repeating blink patterns without firmware loop. Use Value: Reduces host processor load and eliminates need for external timers or PWM peripherals - simplifies BOM and firmware design. |
Use Scenario: Animated lighting in consumer electronics toys, promotional gadgets, and interactive wearables requiring dynamic color transitions. IC Role / Device Role / Timing Role: LM2755TMX/NOPB operates as trapezoidal waveform generator with independent ramp-up/ramp-down timing per channel for smooth breathing effects. Use Value: Achieves visually pleasing, non-flickering light modulation using only I²C register writes - no real-time MCU timing constraints or jitter concerns. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3530TMX/NOPB | Uses linear regulator architecture (no charge pump); fixed 3-channel 25mA max; I²C with 256-step linear dimming. | Better suited for low-VF LEDs (<3.2V) and ultra-low-noise applications; lower efficiency at higher VF or low VIN. | Select when EMI sensitivity prohibits switching topologies and VF is stable below 3.0V. |
| TPS61165DRVR | Inductor-based boost converter; single-output; 40V max VOUT; analog + PWM dimming; no trapezoidal control. | Supports higher LED strings (e.g., 3–5 white LEDs in series); lacks per-channel timing control and exponential dimming. | Select when driving >3.6V total VF or requiring >30mA per channel with higher voltage headroom. |
Compared with LM3530TMX/NOPB and TPS61165DRVR, the LM2755TMX/NOPB uniquely combines inductorless operation, per-channel trapezoidal dimming, and exponential brightness scaling - making it optimal for compact, low-EMI, multi-LED UI lighting where visual quality and layout simplicity are prioritized over ultra-high VF support.
Availability
LM2755TMX/NOPB is available at Aetrix Electronics and suitable for keypad backlighting, display backlighting, indicator lighting, and fun-light effects requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM2755TMX/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 expertise in precision power conversion and human-interface solutions.
The LM2755TMX/NOPB belongs to TI's LED driver product line, designed specifically for space-constrained, low-EMI portable UI lighting applications requiring high efficiency, flexible dimming, and minimal external components.
FAQ
What is the maximum LED forward voltage supported by the LM2755TMX/NOPB?
The LM2755TMX/NOPB supports LED forward voltages up to approximately 4.6V when operating in 3/2× charge pump mode with VIN ≥ 3.2V. At VIN = 3.6V, the regulated POUT voltage is ~4.6V (typ.), allowing reliable operation with common white LEDs (VF ≈ 3.0–3.6V). The device monitors VDx headroom and switches gain modes dynamically to maintain regulation - no manual configuration is required.
How does the LM2755TMX/NOPB achieve 90% peak efficiency without an inductor?
The LM2755TMX/NOPB achieves 90% peak efficiency using a switched-capacitor (charge pump) topology with adaptive 1×/3/2× gain selection. It avoids inductor losses by transferring energy via low-ESR ceramic capacitors and minimizes conduction loss through optimized internal MOSFET sizing and synchronous rectification. Efficiency remains >80% across 2.7V–5.5V input and 10–30mA load ranges.
Can the LM2755TMX/NOPB drive more than three LEDs?
The LM2755TMX/NOPB has three dedicated current-sink outputs (ID1–ID3), each capable of driving one LED or parallel-connected LEDs totaling ≤30mA. Driving more than three discrete LEDs requires multiple LM2755TMX/NOPB devices - enabled by dual I²C addresses (0x18/0x67 via ADDR pin) - or external current-sharing circuitry, which is not recommended due to mismatch and thermal risks.
What is the role of the ISET pin on the LM2755TMX/NOPB?
The ISET pin on the LM2755TMX/NOPB sets the full-scale LED current for all three channels via an external resistor to GND. With an internal 1.25V reference and 200× current gain, a 12.5kΩ resistor yields 20mA per channel (IDx = 200 × 1.25V / 12.5kΩ). This analog scaling provides stable, temperature-compensated current setting independent of I²C register values.
Does the LM2755TMX/NOPB require external flying capacitors, and what values are recommended?
Yes, the LM2755TMX/NOPB requires two external 0.47µF ceramic flying capacitors (C1 and C2) connected across its C1+/C1− and C2+/C2− pins. TI recommends TDK C1005X5R1A474M (0402, X5R, 10V) or equivalent MLCCs. These capacitors must be placed symmetrically and as close as possible to the IC to minimize parasitic inductance and ensure stable charge transfer and low EMI.
LM2755TMX/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:
- 3
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- -
- Current - Output / Channel:
- 30mA
- Frequency:
- 1.25MHz
- Dimming:
- I2C
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 18-DSBGA
LM2755TMX/NOPB FAQ
1.How can I place an order for LM2755TMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2755TMX/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 LM2755TMX/NOPB reliable?
The price and inventory of LM2755TMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2755TMX/NOPB is usually 5 days.
3.What payment methods are accepted for LM2755TMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2755TMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2755TMX/NOPB?
LM2755TMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2755TMX/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 LM2755TMX/NOPB?
For technical support, including LM2755TMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2755TMX/NOPB requirements.
6.How does Aetrix verify that LM2755TMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2755TMX/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 LM2755TMX/NOPB meets industry standards.
7.What is the process for return or replacement of LM2755TMX/NOPB?
All LM2755TMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2755TMX/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 LM2755TMX/NOPB part is unused and in its original packaging.
Return procedure for LM2755TMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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