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Texas Instruments LM3553SDX/NOPB
- Part No.:
- LM3553SDX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LM3553SDX/NOPB.pdf
- Description:
- IC LED DRV RGLTR I2C 1.2A 12WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,397
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Product details
Overview
LM3553SDX/NOPB from Texas Instruments is a fixed-frequency, current-mode step-up DC/DC converter with dual regulated current sinks, designed for LED flash applications in camera phones and smartphones. It delivers up to 1.2A total (600mA per channel) across two series LEDs from a 2.7–5.5V input, features I²C-compatible control, programmable flash safety timer (50–3200 ms), and 90% peak efficiency.
For engineers reviewing the LM3553SDX/NOPB datasheet, LM3553SDX/NOPB pinout, LM3553SDX/NOPB application, or LM3553SDX/NOPB equivalent, this page provides verified technical context, validated pin functions, real-world operating modes (Flash/Torch/Indicator/Voltage), confirmed thermal and electrical specifications, and two rigorously cross-checked alternative drivers for mobile LED systems.
Technical Context
The LM3553SDX/NOPB integrates a 1.2 MHz switching controller with NMOS power switch (RDS(ON) = 0.25 Ω), dual current-sink regulation (VD1/VD2 = 350 mV or 450 mV), and hardware synchronization via TX and FEN pins. Its current matching between D1/D2 is ±2%, and over-voltage protection is configurable at 5.6 V (low-voltage mode) or 18.9 V (high-voltage mode).
It supports four operational modes-Flash, Torch, Indicator (20 mA), and Voltage Mode (4.98 V)-all selectable via I²C registers (e.g., General Purpose Register 0x10). The M/F pin serves as either hardware RESET or GPIO, configured through Multi-Function Control Register (0x20), and the device includes thermal shutdown at 140°C (typ.) with automatic recovery at 120°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 5.5 V - supports single-cell Li-ion battery operation without external LDO. |
| Max Flash Current | 1.2 A total (600 mA per channel) - enables high-brightness dual-LED flash with programmable 128-step scaling. |
| Switching Frequency | 1.2 MHz (typ.) - allows compact 2.2 µH inductor and <30 mm² total solution size. |
| Current Sink Matching | ±2% - ensures balanced brightness and thermal load across two series-connected LEDs. |
| OVP Trip Point | 5.6 V (OVP bit = '0') - protects against overvoltage during boost operation with 0.6 V hysteresis. |
| I²C Address | 0x53 (7-bit) - enables standard SMBus-compatible communication with 100 kHz/400 kHz timing compliance. |
| Thermal Shutdown | 140°C (typ.) - prevents permanent damage under sustained high-power flash duty cycles. |
Pinout & Package
LM3553SDX/NOPB uses a 12-pin WSON package (DQB0012A): 3 mm × 3 mm × 0.8 mm, 0.4 mm pitch, with exposed die-attach pad (DAP) for thermal dissipation (θJA = 36.7°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISET | Current sense reference | Connects to 16.5 kΩ resistor to set full-scale LED current (1.2 A); voltage = 1.24 V. |
| VIN | Main power input | Accepts 2.7–5.5 V; powers internal circuitry and switching stage; requires ≥10 µF ceramic input capacitor. |
| SW | Power switch node | Drives external 2.2 µH inductor; peak current limited to 2.5 A (OCL = '0') or 1.7 A (OCL = '1'). |
| OVP | Over-voltage protection monitor | Configurable trip point (5.6 V or 18.9 V); enables safe operation with single or dual-series LED strings. |
| D1 / D2 | Regulated current sink outputs | Each sinks up to 600 mA; voltage compliance ≥500 mV; matched within ±2% for uniform LED drive. |
| FEN | Hardware flash enable | Pull-high initiates flash; pull-low terminates early; external pull-down required for startup stability. |
| TX | RF PA synchronization input | High forces Torch mode during flash - synchronizes LED pulse with RF transmit burst to avoid interference. |
| SCL / SDA | I²C interface signals | Support standard-mode (100 kHz) and fast-mode (400 kHz); VIO referenced; require pull-ups to VIO. |
| VIO | Digital I/O reference | Sets logic thresholds for SCL/SDA/M/F; range = 1.45 V to VIN; decouples digital supply from analog rails. |
| M/F | Multi-function pin | Configurable as active-low hardware RESET (default) or GPIO via register 0x20; supports GPI/GPO modes. |
| GND / DAP | Ground and thermal pad | Exposed DAP must be soldered to PCB ground plane for thermal performance and EMI reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable Flash Safety Timer | 16 discrete durations (50–3200 ms) - prevents LED overheating and battery overcurrent during extended flash events. |
| Four Operating Modes | Flash (1.2 A), Torch (programmable ≤1.2 A), Indicator (20 mA), Voltage Mode (4.98 V) - enables flexible system-level lighting control. |
| LED Disconnect During Shutdown | Zero leakage path from D1/D2 to GND - eliminates standby current drain and prevents unintended LED glow. |
| Flash/Imager Synchronization | FEN and TX pins support precise timing coordination with camera sensor and RF power amplifier - critical for noise-free image capture. |
| Adjustable Over-Voltage Protection | Two OVP thresholds (5.6 V or 18.9 V) - supports both single-LED (≤3.7 V) and dual-series (≤7.4 V) configurations without redesign. |
| Total Solution Size | <29.25 mm² - achieved with 3 mm × 3 mm IC, 2.2 µH inductor, and 10 µF/4.7 µF MLCCs - meets tight mobile PCB area constraints. |
Applications
| Camera Phone LED Flash | Smartphone Dual-LED Flash |
|---|---|
|
Use Scenario: High-intensity illumination for low-light photography in sub-10 mm-thick mobile handsets. IC Role / Device Role / Timing Role: Dual-channel current sink driver with synchronized TX/FEN control ensures flash pulse aligns precisely with image sensor integration time and RF PA burst. Use Value: Delivers 600 mA per LED at 3.0 V input with 90% efficiency, enabling 1.2 A total flash current within thermal limits of compact form factor. |
Use Scenario: Brightness-matched dual-LED flash in flagship smartphones requiring programmable current and safety timer. IC Role / Device Role / Timing Role: I²C-configurable current regulator with ±2% D1/D2 matching and 128-step brightness control for consistent color temperature and luminance. Use Value: Supports 50–3200 ms flash duration via register 0xC0, meeting JEITA and OEM-defined safety and thermal derating requirements. |
| LED Indicator Lighting | Mobile Voltage Mode Backlight |
|
Use Scenario: Low-power status indication (e.g., charging, notification) using single LED in always-on portable devices. IC Role / Device Role / Timing Role: Hardware-enabled Indicator Mode (EN0=1, EN1=0) delivering fixed 20 mA with no software overhead. Use Value: Draws only 1.2 mA quiescent current (IQ) and 6 µA shutdown current (ISD), extending battery life in standby. |
Use Scenario: Boosted voltage source for white LED backlight in small displays where dedicated boost IC is impractical. IC Role / Device Role / Timing Role: Voltage Mode operation (VM=1) regulates output to 4.98 V with ±0.33 V accuracy, independent of LED string count. Use Value: Eliminates need for separate boost converter; leverages existing LM3553SDX/NOPB footprint and BOM for dual-purpose use. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED flash driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3554SDX/NOPB | Higher max current (1.5 A total), integrated thermal foldback, same 12-pin WSON package and pinout. | Targeted at higher-lumen flash modules requiring >1.2 A; adds thermal derating but increases BOM cost. | Select when peak flash brightness exceeds 1.2 A capability and thermal margin is constrained. |
| RT8548GQW | Fixed 1.0 A max flash current, no Voltage Mode, different I²C address (0x34), 16-pin QFN package. | Designed for cost-sensitive mid-tier smartphones; lacks torch synchronization and OVP flexibility. | Choose for simplified designs where 1.0 A suffices and board space allows larger 4×4 mm QFN footprint. |
Compared with LM3553SDX/NOPB, LM3554SDX/NOPB offers higher current headroom and thermal protection at identical layout compatibility, while RT8548GQW trades feature depth for lower unit cost and simpler register mapping - making each suitable for distinct tiered design goals.
Availability
LM3553SDX/NOPB is available at Aetrix Electronics and suitable for camera phone flash, smartphone dual-LED systems, and mobile indicator lighting requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM3553SDX/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 ICs, with decades of expertise in mobile power and lighting solutions.
The LM3553SDX/NOPB belongs to TI's mobile LED driver product line, engineered specifically for high-efficiency, thermally robust flash illumination in space-constrained consumer handhelds.
FAQ
What is the maximum LED current supported by the LM3553SDX/NOPB?
The LM3553SDX/NOPB supports up to 1.2 A total LED current, split equally across D1 and D2 (600 mA per channel) when driving two LEDs in series. This is achieved using a 16.5 kΩ resistor on the ISET pin and full-scale programming (brightness code 127) in Flash Mode. Current is digitally adjustable in 128 steps, and the device maintains ±2% matching between channels under all operating conditions.
How does the TX pin function in the LM3553SDX/NOPB?
The TX pin on the LM3553SDX/NOPB provides hardware-level synchronization with the RF power amplifier: when driven high during a flash event, it forces the device into Torch Mode, reducing LED current to prevent interference with cellular transmission. Once TX returns low, the LM3553SDX/NOPB resumes flash current if within the programmed safety timer window. An external pull-down resistor is mandatory to avoid spurious activation at power-up.
Can the LM3553SDX/NOPB drive a single LED instead of two in series?
Yes, the LM3553SDX/NOPB can drive a single LED at up to 1.2 A by configuring the VFB bit to '0' (450 mV regulation voltage) and enabling only D1 via the General Purpose Register (EN0=1, EN1=0 for Torch or Flash). The OVP threshold must be set to 5.6 V (OVP bit = '0') to match typical single-LED forward voltage (~3.3–3.7 V), and COUT should be 10 µF (not 4.7 µF) per datasheet recommendations.
What is the purpose of the M/F pin on the LM3553SDX/NOPB?
The M/F pin on the LM3553SDX/NOPB is a multi-function terminal configurable as either an active-low hardware RESET (default) or a general-purpose I/O (GPIO) via register 0x20. In GPIO mode, it operates as input (GPI) or output (GPO) depending on the MODE bit; data is latched on I²C writes. Unlike RESET, GPIO functionality requires exiting RESET state first - a two-write sequence is needed to assert GPO high after power-on.
Does the LM3553SDX/NOPB include thermal protection?
Yes, the LM3553SDX/NOPB includes internal thermal shutdown that activates at 140°C (typical junction temperature) and releases at 120°C (typical), preventing permanent damage during sustained high-current flash operation. This protection is independent of external components and works alongside the programmable flash safety timer (register 0xC0) to provide layered thermal management for mobile applications.
LM3553SDX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 12-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- -
- Current - Output / Channel:
- 1.2A (Flash)
- Frequency:
- 1.2MHz
- Dimming:
- I2C
- Applications:
- Backlight, Camera Flash
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-WSON (3x3)
LM3553SDX/NOPB FAQ
1.How can I place an order for LM3553SDX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3553SDX/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 LM3553SDX/NOPB reliable?
The price and inventory of LM3553SDX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3553SDX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3553SDX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3553SDX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3553SDX/NOPB?
LM3553SDX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3553SDX/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 LM3553SDX/NOPB?
For technical support, including LM3553SDX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3553SDX/NOPB requirements.
6.How does Aetrix verify that LM3553SDX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3553SDX/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 LM3553SDX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3553SDX/NOPB?
All LM3553SDX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3553SDX/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 LM3553SDX/NOPB part is unused and in its original packaging.
Return procedure for LM3553SDX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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