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Texas Instruments LM3553SD/NOPB
- Part No.:
- LM3553SD/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LM3553SD/NOPB.pdf
- Description:
- IC LED DRV RGLTR I2C 1.2A 12WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,566
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Product details
Overview
LM3553SD/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 mobile cameras. It delivers up to 1.2A total (600mA per channel) across two series-connected LEDs from a 2.7–5.5V input, features I²C-compatible control (7-bit address 0x53), programmable flash safety timer (50–3200 ms), and integrated over-voltage protection (5.4–19.65V trip range). It operates in Flash, Torch, Indicator, and Voltage modes.
For engineers reviewing the LM3553SD/NOPB datasheet, LM3553SD/NOPB pinout, LM3553SD/NOPB application, or LM3553SD/NOPB equivalent, this page provides verified technical context, validated pin functions, confirmed operating modes, real-world efficiency data (up to 90% peak), and precise alternative part comparisons - all grounded in TI's SNVS414B revision May 2013 specification.
Technical Context
The LM3553SD/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 depending on VFB bit), and thermal shutdown (140°C engage). Its I²C interface supports register-based configuration of flash/torch current (128-step resolution), duration (16-step safety timer), and multi-function pin behavior (RESET/GPIO).
It implements RF synchronization via TX pin (forces Torch mode during PA transmission) and flash initiation via FEN pin (hardware-triggered, non-I²C), while supporting voltage-mode operation (4.98 V regulated output) when VM bit is set. The device uses external RSET (e.g., 16.5 kΩ for 1.2 A full-scale) to calibrate LED current accuracy (±2% sink matching, ±6770 A/A ratio).
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 Total LED Current | 1.2 A (600 mA per channel) - enables high-brightness dual-LED flash at 3.0 V input. |
| Switching Frequency | 1.2 MHz (typ.) - allows compact 2.2 µH inductor and low-profile layout (<29.25 mm² solution size). |
| Current Sink Matching | ±2% - ensures balanced brightness and thermal load between D1 and D2 outputs. |
| OVP Trip Range | 5.4 V to 19.65 V - selectable via OVP bit for single-LED (low-V) or series-LED (high-V) configurations. |
| I²C Address | 0x53 (7-bit) - enables multi-device bus sharing with standard SCL/SDA timing (t1 ≥2.5 µs). |
| Thermal Shutdown | 140°C engage / 120°C disengage - protects IC under sustained high-current or poor PCB thermal design. |
Pinout & Package
LM3553SD/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) thermally connected to GND. The DAP must be soldered to a PCB thermal pad for optimal junction-to-ambient thermal resistance (θJA = 36.7°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power input | Accepts 2.7–5.5 V; internal UVLO prevents operation below 2.5 V. |
| SW | Switch node | Connects to inductor and Schottky diode anode; rated for 25 V max, 2.5 A peak current. |
| OVP | Over-voltage sense | Monitors output voltage; sets OVP threshold (low/high range) via register-controlled OVP bit. |
| D1, D2 | LED current sinks | Each regulates current to external LED cathodes; 350/450 mV compliance voltage selectable. |
| GND | Ground reference | Includes dedicated pins (2, 11) and DAP - all must be low-impedance to minimize noise and thermal rise. |
| ISET | Current calibration | Connects to 1% RSET (e.g., 16.5 kΩ); sets full-scale current via 1.24 V reference and 6770 A/A ratio. |
| FEN | Hardware flash enable | Pull-high initiates flash; pull-low terminates early - bypasses I²C for low-latency triggering. |
| SCL, SDA | I²C interface | Supports standard-mode I²C (≤400 kHz); VIO referenced (1.45–VIN); requires external pull-ups. |
| VIO | Digital supply | Sets logic thresholds for SCL/SDA; independent of VIN (1.45 V min) - enables mixed-voltage system interfacing. |
| TX | RF sync control | Pull-high forces Torch mode during flash - synchronizes LED pulse with RF PA transmit window. |
| M/F | Multi-function I/O | Configurable as hardware RESET (default) or GPIO via register 0x20; supports GPI/GPO modes. |
Key Features
| Feature | Design Value |
|---|---|
| Dual current sinks with 2% matching | Ensures uniform brightness and thermal distribution across two series LEDs without external balancing circuitry. |
| Programmable flash safety timer (16 steps) | Prevents LED overheating by limiting flash duration from 50 ms to 3200 ms - configurable via register 0xC0. |
| I²C-compatible interface (0x53 address) | Enables dynamic current, mode, and timing control from baseband processor - eliminates need for discrete logic. |
| RF synchronization via TX pin | Allows hardware-level coordination between flash pulse and cellular/Wi-Fi transmit events - reduces EMI and battery surge. |
| Four operational modes (Flash/Torch/Indicator/Voltage) | Supports full camera UX stack: high-current flash, steady torch, low-power indicator, and auxiliary 4.98 V rail generation. |
| Adjustable OVP (5.4–19.65 V) | Permits safe operation with both single-LED (3.3–3.8 V) and dual-series-LED (6.6–7.6 V) configurations using same IC. |
Applications
| Camera Phone LED Flash | Smartphone Dual-LED Torch |
|---|---|
Use Scenario: High-intensity still-image capture in low-light conditions using dual white LEDs. IC Role / Device Role / Timing Role: Dual-channel current regulator driving two series-connected LEDs at 600 mA each with synchronized 1.2 MHz boost conversion. Use Value: Delivers 1.2 A total flash current from 3.0 V input with 90% peak efficiency and <30 mm² PCB footprint. |
Use Scenario: Continuous illumination for video recording or UI lighting in handheld devices. IC Role / Device Role / Timing Role: Torch-mode current source with programmable 20–1200 mA output (32-step resolution) and soft-start ramp control. Use Value: Enables flicker-free, thermally stable illumination using same hardware as flash - no additional drivers required. |
| Mobile Device Indicator Light | Compact Camera Module Voltage Rail |
Use Scenario: Low-power status indication (e.g., charging, notification) using single LED. IC Role / Device Role / Timing Role: Indicator-mode current sink delivering fixed 20 mA to D1 while disabling D2. Use Value: Reduces BOM count by reusing flash driver IC for always-on indicators - consumes only 1.2 mA quiescent current. |
Use Scenario: Providing regulated 4.98 V bias to image sensor or imager ASIC in space-constrained modules. IC Role / Device Role / Timing Role: Voltage-mode boost converter (VM bit = '1') with 4.65–5.30 V regulation and 500 mA load capability. Use Value: Eliminates need for separate LDO or buck-boost IC - leverages existing inductor and feedback path for rail generation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED flash driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3554SD/NOPB | Higher 1.5 A max flash current; adds analog torch control (ITORCH pin); identical 12-pin WSON package. | Required for >1.2 A flash demands or analog-dimming torch systems; not drop-in due to added pin function and register map changes. | Select LM3554SD/NOPB when higher peak current or analog torch dimming is needed; LM3553SD/NOPB remains optimal for cost-sensitive 1.2 A designs. |
| RT8548GQW | Fixed 1.2 A flash current; no I²C interface; uses resistor-programmed timing; QFN-16 package (4×4 mm). | Suitable for simpler, lower-BOM-cost flash systems without dynamic current/timing control; larger footprint and less flexible configuration. | Choose RT8548GQW for fixed-function, high-volume applications where I²C overhead is unnecessary and board area is not constrained. |
Compared with LM3554SD/NOPB and RT8548GQW, the LM3553SD/NOPB uniquely balances programmability (I²C), compactness (3×3 mm), and precision (2% current matching) for mainstream smartphone flash subsystems - offering the most direct trade-off between feature richness and integration density.
Availability
LM3553SD/NOPB is available at Aetrix Electronics and suitable for camera phone LED flash, smartphone dual-LED torch, and mobile indicator lighting applications requiring stable component supply and long-term production continuity.
Supply support for LM3553SD/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 portable power and LED driver innovation.
The LM3553SD/NOPB belongs to TI's mobile LED flash driver product line, engineered specifically for space-constrained, battery-powered imaging systems requiring high-efficiency, multi-mode LED control and RF-aware timing synchronization.
FAQ
What is the maximum LED current supported by the LM3553SD/NOPB?
The LM3553SD/NOPB supports up to 1.2 A total LED current, split equally across its two current sinks (D1 and D2) - i.e., 600 mA per channel. This is achieved using a 16.5 kΩ 1% RSET resistor on the ISET pin. Full-scale current is programmable down to 500 mA (via 28 kΩ RSET) or 1 A (16.8 kΩ), and fine-tuned in 128 discrete steps via the Flash Current Control register (0xB0).
How does the LM3553SD/NOPB synchronize with RF power amplifiers?
The LM3553SD/NOPB uses its TX pin to synchronize flash pulses with RF transmit events: pulling TX high forces immediate transition to Torch mode, pausing flash current delivery until TX returns low. This prevents simultaneous high-current LED and RF PA operation - reducing battery voltage droop and EMI coupling. The behavior is hardware-asserted and does not require I²C intervention.
Can the LM3553SD/NOPB drive a single LED instead of two series LEDs?
Yes, the LM3553SD/NOPB can drive a single LED using only D1 (with D2 disabled) or both D1 and D2 in parallel (via register configuration). When configured for single-LED operation, the OVP pin is set to low-voltage mode (OVP bit = '0'), enabling a 5.4–5.85 V trip point appropriate for typical 3.3–3.8 V white LEDs. The device maintains full 1.2 A capability in this configuration.
What is the purpose of the M/F pin on the LM3553SD/NOPB?
The M/F pin on the LM3553SD/NOPB is a multi-function terminal configurable as either a hardware RESET input (default) or general-purpose I/O (GPIO). Its behavior is controlled by the Multi-Function Pin Control Register (0x20): RESET = '0' enables hardware reset (logic low resets registers), while RESET = '1' and MODE = '0' configures it as GPI, and MODE = '1' as GPO - all without external components.
Does the LM3553SD/NOPB include thermal protection?
Yes, the LM3553SD/NOPB includes internal thermal shutdown that engages at TJ ≈ 140°C (typical) and disengages at TJ ≈ 120°C (typical). This protection is independent of ambient temperature and activates under sustained high-current operation or inadequate PCB thermal design. The 36.7°C/W junction-to-ambient thermal resistance (θJA) assumes proper DAP soldering to a thermal pad.
LM3553SD/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)
LM3553SD/NOPB FAQ
1.How can I place an order for LM3553SD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3553SD/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 LM3553SD/NOPB reliable?
The price and inventory of LM3553SD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3553SD/NOPB is usually 5 days.
3.What payment methods are accepted for LM3553SD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3553SD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3553SD/NOPB?
LM3553SD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3553SD/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 LM3553SD/NOPB?
For technical support, including LM3553SD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3553SD/NOPB requirements.
6.How does Aetrix verify that LM3553SD/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3553SD/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 LM3553SD/NOPB meets industry standards.
7.What is the process for return or replacement of LM3553SD/NOPB?
All LM3553SD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3553SD/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 LM3553SD/NOPB part is unused and in its original packaging.
Return procedure for LM3553SD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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