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Texas Instruments LM3644YFFR
- Part No.:
- LM3644YFFR
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 12-UFBGA, DSBGA
- Datasheet:
-
LM3644YFFR.pdf
- Description:
- IC LED DRV RGLTR I2C 12DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:4,531
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Product details
Overview
LM3644YFFR from Texas Instruments is a dual 1.5-A high-side current source LED flash driver with synchronous boost converter, operating from 2.5 V to 5.5 V input and delivering programmable flash currents up to 1.5 A per channel and torch currents up to 179 mA per channel. It features hardware strobe (STROBE), torch/temperature sense (TORCH/TEMP), and TX synchronization inputs for RF power amplifier coordination in smartphone camera modules.
For engineers reviewing the LM3644YFFR datasheet, LM3644YFFR pinout, LM3644YFFR application, or LM3644YFFR equivalent, this page delivers verified technical context, validated pin functions, confirmed torch/flash timing behavior, I²C register-controlled dual-current sourcing, and thermal management via NTC monitoring - all specific to the YFFR DSBGA-12 package.
Technical Context
The LM3644YFFR integrates a fixed-frequency (2 MHz or 4 MHz) synchronous boost converter with dual independent high-side current sources, each regulated to maintain ≥158 mV headroom (VHR) across LED1/LED2 under torch conditions and ≥290 mV under flash. Its adaptive regulation ensures current-source compliance across varying LED forward voltages and input supply levels.
Control logic supports three operational modes: Flash (ramped 128-level current up to 1.5 A), Torch (ramped 128-level current up to 179 mA), and IR (instant on/off using flash registers). Hardware pins - STROBE (active-high flash enable), TORCH/TEMP (dual-function torch enable or NTC threshold detection), and TX (synchronization interrupt) - operate with internal 300 kΩ pulldown resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5 V to 5.5 V - supports single-cell Li-ion and Li-poly battery operation without external LDO. |
| Max Flash Current per Channel | 1.5 A - enables high-intensity white LED flash illumination for low-light photography. |
| Max Torch Current per Channel | 179 mA - provides stable video lighting with thermal derating via NTC monitoring on TORCH/TEMP pin. |
| Flash Timeout Range | 10 ms to 400 ms - programmable via register to prevent LED overheating during burst flash sequences. |
| Switching Frequency | 2 MHz or 4 MHz - allows use of ultra-small 1 µH inductors and 10 µF ceramic output capacitors. |
| I²C Address | 0x63 - standard 7-bit address enabling multi-device bus configuration without address conflict. |
| Thermal Shutdown Threshold | 150°C (typical) - protects device during sustained high-current operation; resumes at 135°C. |
Pinout & Package
LM3644YFFR uses a 12-pin DSBGA (Die Size Ball Grid Array) package measuring 1.69 mm × 1.31 mm, optimized for space-constrained mobile camera modules. The package features bottom-side solder balls for compact PCB layout and improved thermal conduction to the board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (A1) | Ground reference | Primary return path for all internal circuits and LED current sinks; must be low-impedance connection to system ground plane. |
| IN (A2) | Power input | Connects to 2.5–5.5 V supply; requires ≥10 µF ceramic bypass capacitor to GND for stable boost operation. |
| SDA (A3) | I²C data line | Open-drain bidirectional serial data interface; pulled up externally to VIN or IOVDD (1.8 V typical). |
| SW (B1) | Switch node | Internal NMOS/PMOS switch junction; connects to external 1 µH inductor and determines boost converter efficiency. |
| STROBE (B2) | Hardware flash trigger | Active-high input with 300 kΩ internal pulldown; initiates flash sequence immediately upon rising edge. |
| SCL (B3) | I²C clock line | Input-only clock signal; supports 400 kHz I²C timing with defined setup/hold requirements per datasheet. |
| OUT (C1) | Boost converter output | Regulated DC output driving LED anodes; requires 10 µF ceramic capacitor to GND for ripple suppression. |
| HWEN (C2) | Hardware enable/reset | Active-high standby control; pulling low resets internal registers and forces shutdown state. |
| TORCH/TEMP (C3) | Torch enable / NTC monitor | Dual-function pin: logic HIGH enables torch mode; voltage divider with NTC thermistor triggers current scaling at 0.6 V threshold. |
| LED2 (D1) | High-side LED current source | Drives second white LED anode; delivers up to 1.5 A flash or 179 mA torch with ±7% accuracy at full scale. |
| TX (D2) | RF sync interrupt | Configurable dual-polarity input; asserts interrupt during RF PA pulse to pause flash current and reduce peak battery draw. |
| LED1 (D3) | High-side LED current source | Drives primary white LED anode; identical performance and regulation to LED2, supporting independent brightness control. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 128-step current sources | Enables precise ratio control between LED1 and LED2 for color-matched dual-LED flash systems. |
| Grounded-cathode LED topology | Allows direct thermal coupling of LED cathodes to PCB copper, improving heat dissipation over floating-cathode alternatives. |
| Adaptive headroom regulation (VHR) | Maintains minimum 158 mV (torch) or 290 mV (flash) across current sources to maximize efficiency and minimize dropout loss. |
| IVFM input voltage flash monitor | Reduces programmed flash current when VIN drops below 2.9 V (typical), preventing battery sag-induced system reset. |
| Small solution size < 16 mm² | Integrates boost controller, dual current sources, and protection circuitry into a 1.69 mm × 1.31 mm DSBGA package. |
| NTC-based thermal foldback | Uses external NTC on TORCH/TEMP pin to scale down torch current before reaching critical LED junction temperature. |
Applications
| Smartphone Camera Flash | Digital Still Camera Module |
|---|---|
|
Use Scenario: Dual-white LED flash illumination in compact smartphone rear cameras during low-light capture. IC Role / Device Role / Timing Role: Dual high-side current source providing synchronized 1.5-A flash pulses with hardware-triggered STROBE and TX-synchronized interruption. Use Value: Enables high-luminance, thermally safe flash bursts while coordinating with RF transmission to avoid battery voltage collapse. |
Use Scenario: High-fidelity flash control in portable digital still cameras with dual-LED arrays and manual exposure settings. IC Role / Device Role / Timing Role: Independent programmable current source for LED1/LED2, supporting variable flash intensity and duration via I²C registers. Use Value: Delivers repeatable, calibrated flash output across ambient temperatures using NTC-based thermal compensation. |
| Barcode Scanner Illumination | Emergency Strobe Lighting |
|
Use Scenario: Short-duration, high-intensity LED flash for rapid barcode decoding in handheld industrial scanners. IC Role / Device Role / Timing Role: Hardware-triggered flash driver with 10-ms minimum timeout, supporting burst-mode scanning sequences. Use Value: Guarantees consistent LED brightness across battery voltage range (2.5–5.5 V) without software intervention. |
Use Scenario: High-reliability visual alert system in fire alarm panels requiring certified strobe timing and thermal safety. IC Role / Device Role / Timing Role: Torch-mode current source delivering stable 179 mA per LED with automatic thermal derating via NTC. Use Value: Meets UL 1971 strobe luminance requirements while preventing LED thermal runaway during extended operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel LED flash driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3644TTYFFR | Higher max torch current (360 mA vs. 179 mA); extended flash timeout (1.6 s vs. 400 ms). | Required for high-brightness continuous torch operation in premium smartphones; not drop-in due to different current calibration. | Select LM3644TTYFFR only if application demands >179 mA torch current or >400 ms flash duration. |
| RT8546GQW | Single-channel 1.5-A flash driver; no NTC monitoring; no TX sync input; 3.2-MHz fixed switching frequency. | Suitable for cost-sensitive single-LED designs; lacks dual-channel independence and thermal safety features. | Choose RT8546GQW only for single-LED systems where NTC monitoring and RF sync are unnecessary. |
Compared with LM3644TTYFFR, LM3644YFFR offers tighter thermal control at lower torch currents, while RT8546GQW reduces BOM count but sacrifices dual-LED flexibility and safety features essential for certified camera modules.
Availability
LM3644YFFR is available at Aetrix Electronics and suitable for smartphone camera modules, barcode scanners, emergency strobes, and handheld data terminals requiring stable component supply and long-term production continuity.
Supply support for LM3644YFFR 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 and embedded processing technologies, with decades of expertise in power management and LED driver innovation.
The LM3644 product line was designed specifically for space-constrained, battery-powered camera flash applications demanding high efficiency, thermal resilience, and hardware-synchronized timing - targeting mobile, imaging, and safety-critical visual signaling markets.
FAQ
What is the maximum continuous torch current per channel for LM3644YFFR?
The LM3644YFFR supports a maximum torch current of 179 mA per channel (LED1 or LED2), as specified in the Device Comparison Table and confirmed in Section 7.5 Electrical Characteristics. This value is distinct from the LM3644TT variant, which supports 360 mA. Operation above 179 mA in torch mode requires the LM3644TTYFFR part number.
Does LM3644YFFR support hardware-triggered flash without I²C communication?
Yes, LM3644YFFR supports fully autonomous hardware flash triggering via the STROBE pin. When STROBE is driven high, the device initiates the pre-programmed flash sequence (current level, ramp rate, timeout) stored in its registers - no active I²C transaction required during pulse execution.
How does the TORCH/TEMP pin function in LM3644YFFR?
In LM3644YFFR, the TORCH/TEMP pin serves two roles: as a logic input to enable torch mode when pulled high, or as an NTC thermistor monitoring node. When configured for thermal sensing, it compares the divided NTC voltage against a 0.6 V internal reference to initiate current scaling before LED overheating occurs.
What is the purpose of the TX pin on LM3644YFFR?
The TX pin on LM3644YFFR is a configurable synchronization input that interrupts ongoing flash pulses when asserted, allowing coordination with RF power amplifier events. This prevents simultaneous high-current draw from flash and RF circuits, mitigating battery voltage sag and potential system reset.
Can LM3644YFFR operate in pass-through mode, and under what conditions?
Yes, LM3644YFFR enters pass mode when input voltage exceeds LED forward voltage plus current-source headroom (VHR). In this state, the internal PFET conducts continuously instead of switching, reducing switching losses and improving efficiency at high VIN or low VLED conditions - confirmed in Section 8.1 Overview.
LM3644YFFR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 12-UFBGA, DSBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 2
- Voltage - Supply (Min):
- 2.5V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- -
- Current - Output / Channel:
- 1.5A
- Frequency:
- 2MHz, 4MHz
- Dimming:
- I2C
- Applications:
- Camera Flash
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-DSBGA
LM3644YFFR FAQ
1.How can I place an order for LM3644YFFR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3644YFFR 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 LM3644YFFR reliable?
The price and inventory of LM3644YFFR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3644YFFR is usually 5 days.
3.What payment methods are accepted for LM3644YFFR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3644YFFR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3644YFFR?
LM3644YFFR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3644YFFR 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 LM3644YFFR?
For technical support, including LM3644YFFR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3644YFFR requirements.
6.How does Aetrix verify that LM3644YFFR is sourced from the original manufacturer or authorized distributors?
All LM3644YFFR 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 LM3644YFFR meets industry standards.
7.What is the process for return or replacement of LM3644YFFR?
All LM3644YFFR units undergo pre-shipment inspection (PSI). If there is an issue with LM3644YFFR, 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 LM3644YFFR part is unused and in its original packaging.
Return procedure for LM3644YFFR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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