My Inquiry
My Account
Texas Instruments LM3551SD/NOPB
- Part No.:
- LM3551SD/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LM3551SD/NOPB.pdf
- Description:
- IC LED DRIVER RGLTR 1A 14WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,833
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM3551SD/NOPB from Texas Instruments is a fixed-frequency, current-mode step-up DC/DC white LED flash driver with integrated dual low-side NFETs (FET-T and FET-F), 1.25MHz switching frequency, 2.7–5.5V input range, and up to 1A total output current for high-power camera flash applications in single-cell Li-Ion systems.
For engineers reviewing the LM3551SD/NOPB datasheet, LM3551SD/NOPB pinout, LM3551SD/NOPB application, or LM3551SD/NOPB equivalent, key selection considerations include torch/flash mode control via T/F pin, programmable flash timeout via external CFTO, soft-start via CSS, over-voltage protection trip at 12.4V (typ), and shutdown logic (active-high SD pin).
Technical Context
The LM3551SD/NOPB implements a current-mode PWM boost converter architecture with internal 0.165Ω power switch (SW), two dedicated low-side load disconnect FETs (FET-T: 0.98Ω, FET-F: 0.36Ω), and precision 1.265V feedback reference. It supports independent torch (continuous) and flash (pulsed) modes controlled by the T/F pin, with flash timeout enforced by an internal 1.4µA current source charging CFTO to 1.16V threshold.
Operation includes under-voltage lockout (2.48V turn-on), over-voltage protection (12.4V trip), thermal shutdown (140°C), and soft-start via external capacitor on SS pin. The VC compensation node enables loop stability tuning using RC/CC network, while FB pin bias current is 50nA and error amplifier transconductance is 135µmho.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 5.5V - supports full Li-Ion battery discharge curve without brownout. |
| Switching Frequency | 1.25MHz (typ) - enables use of small 4.7µH inductor and low-ESR ceramic capacitors. |
| Total Output Current | Up to 1A - sum of torch (≤200mA) and flash (≤500mA) currents through separate FET paths. |
| Feedback Reference | 1.265V (±2.5mV) - tight regulation enables accurate LED current setting via RT/RF resistors. |
| OVP Trip Voltage | 12.4V (typ) - protects output capacitor, inductor, and SW FET during open-LED fault. |
| Flash Timeout Current | 1.4µA (typ) - charges external CFTO to 1.16V threshold for precise pulse duration control. |
| Shutdown Current | 2.55µA (typ) - ultra-low quiescent draw when SD = VIN, preserving battery life. |
Pinout & Package
LM3551SD/NOPB uses a 14-pin WSON package (4mm × 4mm, non-pullback, exposed die-attach pad) with GND-connected thermal pad for enhanced power dissipation in high-current flash operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply | Accepts 2.7–5.5V Li-Ion input; powers internal circuitry and boost stage. |
| SD | Shutdown control | Active-high logic input (1.2V threshold); internal 1.2MΩ pull-up to VIN ensures default shutdown. |
| T/F | Mode select | Logic level determines operating mode: low = torch (FET-T only), high = flash (FET-T + FET-F). |
| SW | Power switch node | Drives external inductor; integrates 0.165Ω NMOS with 2.1A current limit and 20V max rating. |
| FET-T | Torch FET drain | Connects to torch LED path; 0.98Ω RDS(on), rated ≤200mA continuous. |
| FET-F | Flash FET drain | Connects to flash LED path; 0.36Ω RDS(on), rated ≤500mA pulsed. |
| FB | Current sense feedback | Monitors voltage drop across RT/RF to regulate LED current; 50nA bias current minimizes error. |
| VC | Compensation node | Connects external RC/CC network to stabilize voltage loop; error amp gm = 135µmho. |
| SS | Soft-start control | External capacitor sets ramp rate of internal reference to limit inrush current at startup. |
| FTO | Flash timeout timing | Receives 1.4µA current to charge CFTO; trip at 1.16V disables all FETs and SW if timeout exceeded. |
| OVP | Over-voltage monitor | Grounding disables OVP (not recommended); otherwise triggers shutdown at 12.4V output overvoltage. |
| GND / AGND | Analog/digital ground | AGND must be low-impedance connected to GND; separates analog sensing from power return paths. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-path LED drive | Independent torch (FET-T only) and flash (FET-T + FET-F) current paths enable simultaneous optimization of efficiency and peak brightness. |
| Programmable flash timeout | External CFTO sets precise flash pulse duration (e.g., 1µF → ~0.82s) to prevent LED thermal damage during fault conditions. |
| True load disconnect | In shutdown mode, both FET-T and FET-F are fully off, eliminating leakage paths and reducing system standby current to <3µA. |
| Integrated OVP and UVP | 12.4V OVP and 2.48V UVP thresholds protect against open-LED faults and battery undervoltage, eliminating need for external protection ICs. |
| Low-profile WSON package | 4mm × 4mm, 14-pin WSON with exposed thermal pad delivers >700mA flash current in space-constrained mobile camera modules. |
Applications
| Smartphone Camera Flash | Digital Still Camera (DSC) Torch |
|---|---|
Use Scenario: High-intensity illumination for low-light smartphone photography with rapid flash sequencing and thermal management. IC Role / Device Role / Timing Role: LM3551SD/NOPB acts as the primary flash driver, regulating 700mA flash current via FET-F and 200mA torch current via FET-T under microcontroller T/F pin control. Use Value: Enables dual-mode operation without external MOSFETs, reducing BOM count and PCB area while maintaining 1.25MHz switching for compact passive component selection. | Use Scenario: Continuous white LED illumination for DSC preview, video recording, or macro focusing in portable cameras. IC Role / Device Role / Timing Role: LM3551SD/NOPB operates in torch mode (T/F = low), delivering stable 200mA current through FET-T with soft-start limiting inrush during power-on. Use Value: Provides flicker-free, dimmable torch light using only RT resistor programming and no additional current-sense amplifiers or DACs. |
| Cellular Phone Front-Facing Flash | PDA Video Call Lamp |
Use Scenario: Low-power front-camera flash for video calls and selfies, requiring precise current control and minimal EMI impact on RF sections. IC Role / Device Role / Timing Role: LM3551SD/NOPB supplies 150mA flash current (via scaled RT/RF) in short bursts, synchronized to camera shutter with FTO-based timeout preventing accidental overdrive. Use Value: 1.25MHz fixed frequency allows predictable EMI filtering; integrated FETs eliminate gate-drive layout sensitivity near antenna regions. | Use Scenario: Always-on auxiliary lighting for PDA video conferencing in variable ambient light, demanding long-term reliability and low standby drain. IC Role / Device Role / Timing Role: LM3551SD/NOPB remains in torch mode during active sessions and enters <3µA shutdown between calls via SD pin control from baseband processor. Use Value: True load disconnect and sub-µA shutdown current extend battery runtime in intermittent-use portable devices. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED flash driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3552SD/NOPB | Uses active-high EN pin instead of SD; identical functionality, same pinout, same electrical specs. | No change in torch/flash behavior or timing; differs only in control logic polarity and internal pull-down vs pull-up. | Select LM3552SD/NOPB when system MCU provides active-high enable signal; LM3551SD/NOPB preferred for active-low control or legacy compatibility. |
| TPS61310DSQR | Single-path 1.5A boost driver with I²C interface; no integrated FETs; requires external MOSFETs and current-sense resistors. | Lacks dedicated torch/flash mode separation and flash timeout; supports programmable current via register writes. | Choose TPS61310DSQR for systems needing flexible multi-LED configuration or digital dimming; LM3551SD/NOPB better for cost-sensitive, discrete-component-minimized flash designs. |
Compared with LM3552SD/NOPB, LM3551SD/NOPB offers identical performance but inverted shutdown logic-critical for direct replacement where control signal polarity matches. Versus TPS61310DSQR, LM3551SD/NOPB reduces bill-of-materials and layout complexity by integrating dual FETs and analog mode control, at the expense of digital configurability.
Availability
LM3551SD/NOPB is available at Aetrix Electronics and suitable for smartphone camera flash, digital still camera torch, and cellular phone front-facing illumination requiring stable component supply across high-volume consumer electronics production cycles.
Supply support for LM3551SD/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 conversion and LED driver innovation.
The LM3551SD/NOPB belongs to TI's white LED flash driver product line, engineered specifically for space-constrained, battery-powered imaging systems requiring high-efficiency, dual-mode (torch/flash) LED current regulation with integrated protection features.
FAQ
What is the maximum continuous current LM3551SD/NOPB can deliver in torch mode?
The LM3551SD/NOPB delivers up to 200mA continuously in torch mode using only the FET-T path. This is set by the RT resistor and limited by FET-T's 0.98Ω RDS(on) and thermal design; exceeding this risks thermal shutdown at ambient >85°C. The LM3551SD/NOPB datasheet specifies 200mA as the safe continuous rating for FET-T under typical PCB layout conditions.
How does the flash timeout function work on LM3551SD/NOPB?
When LM3551SD/NOPB is in flash mode (T/F = high and SD = low), a precise 1.4µA current charges the external CFTO capacitor. Once the voltage across CFTO reaches 1.16V, the LM3551SD/NOPB disables all FETs and the SW node, terminating the flash pulse. Reset requires toggling SD or T/F. This prevents LED overheating during controller faults or software hangs.
Can LM3551SD/NOPB drive multiple LEDs in series?
No - the LM3551SD/NOPB is designed for single-string white LED loads with forward voltages up to ~11V (limited by OVP). Its architecture uses low-side current sensing via RT/RF resistors referenced to GND, making it incompatible with series-connected LEDs that require high-side or floating current regulation. For multi-LED strings, a boost+SEPIC or buck-boost topology with high-side sensing is required.
What is the purpose of the VC pin on LM3551SD/NOPB?
The VC pin on LM3551SD/NOPB is the error amplifier output node used for loop compensation. Connecting an RC/CC network between VC and GND sets a dominant pole-zero pair to stabilize the voltage feedback loop against the right-half-plane zero inherent in boost converters. Proper VC network design ensures ≥45° phase margin and robust transient response under varying LED load and input voltage conditions.
Is LM3551SD/NOPB RoHS-compliant and lead-free?
Yes - LM3551SD/NOPB carries the /NOPB suffix, indicating "No Lead Plating" and full compliance with RoHS Directive 2011/65/EU. It uses lead-free matte tin finish on terminals and meets JEDEC J-STD-020 moisture sensitivity level 2a (MSL-2a) for surface-mount assembly. The WSON package is halogen-free and compliant with IPC-1752 material declaration requirements.
LM3551SD/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 1A (Flash)
- Frequency:
- 1.25MHz
- Dimming:
- -
- Applications:
- Camera Flash
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-WSON (4x4)
LM3551SD/NOPB FAQ
1.How can I place an order for LM3551SD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3551SD/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 LM3551SD/NOPB reliable?
The price and inventory of LM3551SD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3551SD/NOPB is usually 5 days.
3.What payment methods are accepted for LM3551SD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3551SD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3551SD/NOPB?
LM3551SD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3551SD/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 LM3551SD/NOPB?
For technical support, including LM3551SD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3551SD/NOPB requirements.
6.How does Aetrix verify that LM3551SD/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3551SD/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 LM3551SD/NOPB meets industry standards.
7.What is the process for return or replacement of LM3551SD/NOPB?
All LM3551SD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3551SD/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 LM3551SD/NOPB part is unused and in its original packaging.
Return procedure for LM3551SD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3551SD/NOPB 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…
