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Texas Instruments LM3644TTYFFR
- Part No.:
- LM3644TTYFFR
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 12-UFBGA, DSBGA
- Datasheet:
-
LM3644TTYFFR.pdf
- Description:
- IC LED DRV RGLTR I2C 12DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:3,960
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Product details
Overview
LM3644TTYFFR from Texas Instruments is a dual 1.5-A high-side current source LED flash driver with 2-MHz/4-MHz synchronous boost converter, 360 mA maximum torch current per channel, 40 ms–1600 ms programmable flash timeout, and grounded-cathode LED operation for thermal optimization-designed for smartphone camera flash systems requiring precise dual-LED brightness control under varying battery conditions.
For engineers reviewing the LM3644TTYFFR datasheet, LM3644TTYFFR pinout, LM3644TTYFFR application, or LM3644TTYFFR equivalent, key selection considerations include its DSBGA-12 package (1.69 mm × 1.31 mm), I²C address 0x63, hardware strobe (STROBE) and torch/temperature (TORCH/TEMP) inputs, adaptive IVFM low-battery current scaling, and NTC-based thermal derating capability.
Technical Context
The LM3644TTYFFR implements a fixed-frequency (2 MHz or 4 MHz), current-mode PWM synchronous boost converter to supply dual independent high-side 128-step current sources. Its adaptive regulation maintains ≥270 mV headroom (VHR) across LED1/LED2 at 360 mA torch current, ensuring regulation even as input voltage drops to 2.5 V.
Hardware control pins-STROBE (active-high flash enable), TORCH/TEMP (dual-function torch enable or NTC thermistor input), and TX (RF PA synchronization interrupt)-operate with internal 300 kΩ pulldown resistors. I²C interface (400 kHz) configures flash/torch currents, timeout, current limit, and thermal thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Torch Current | 360 mA per channel-enables bright continuous illumination for video recording without thermal shutdown in compact mobile form factors. |
| Flash Timeout Range | 40 ms to 1600 ms-supports both rapid burst flash and extended emergency strobe timing via register configuration. |
| Input Voltage Range | 2.5 V to 5.5 V-fully compatible with single-cell Li-ion (3.0–4.2 V nominal) and USB-powered systems. |
| Switching Frequency | 2 MHz or 4 MHz-permits use of ultra-small 1 µH inductors and 10 µF ceramic capacitors, minimizing solution size to <16 mm². |
| Current Accuracy | ±10% at 360 mA torch-ensures consistent luminance matching between dual LEDs across temperature (−40°C to +85°C). |
| I²C Address | 0x63 (7-bit)-allows direct integration into multi-peripheral mobile SoC designs without address conflict. |
| VHR (Headroom) | 270 mV at 360 mA-guarantees current source regulation margin during low-VIN conditions, preserving flash intensity down to 2.5 V input. |
Pinout & Package
LM3644TTYFFR uses a 12-pin DSBGA package (1.69 mm × 1.31 mm, 0.4 mm pitch) optimized for space-constrained mobile camera modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (A1) | Ground reference | Primary return path for boost converter, current sources, and logic; requires low-inductance PCB connection to minimize noise coupling. |
| IN (A2) | Power input | Accepts 2.5–5.5 V supply; must be bypassed with ≥10 µF ceramic capacitor directly to GND for stable boost operation. |
| SDA (A3) | I²C data line | Open-drain bidirectional interface; requires external pull-up to VIN or IOVDD (1.8 V typical) for 400 kHz communication. |
| SW (B1) | Switch node | Internal NMOS/PMOS drain connection; connects to boost inductor; critical for EMI layout and thermal dissipation. |
| STROBE (B2) | Hardware flash trigger | Active-high input with 300 kΩ internal pulldown; initiates flash sequence immediately without I²C latency. |
| SCL (B3) | I²C clock line | Input-only clock signal; synchronizes register reads/writes; shares same pull-up as SDA. |
| OUT (C1) | Boost output | Regulated DC output driving LED anodes; connects to 10 µF ceramic capacitor to GND for ripple suppression. |
| HWEN (C2) | Hardware enable/reset | Active-high standby control; pulling low resets registers and forces shutdown; internal 300 kΩ pulldown ensures safe default state. |
| TORCH/TEMP (C3) | Torch enable or NTC input | Configurable pin: logic HIGH enables torch mode; connected to NTC thermistor enables automatic current derating at high temperature. |
| LED2 (D1) | High-side current source | Drives second flash LED anode; delivers up to 360 mA torch or 1.5 A flash with matched accuracy to LED1. |
| TX (D2) | RF PA sync interrupt | Dual-polarity input (configurable) to pause flash pulse during high-current RF transmission events, preventing battery droop. |
| LED1 (D3) | High-side current source | Drives primary flash LED anode; fully independent current programming and ramp control versus LED2. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 128-level current sources | Enables precise brightness ratio control between LED1 and LED2-critical for color-matching white balance in dual-LED camera flashes. |
| IVFM (Input Voltage Flash Monitor) | Automatically scales flash current downward when VIN falls below 2.9 V threshold-prevents system brownout during high-power flash pulses. |
| NTC thermistor monitoring via TORCH/TEMP | Provides real-time LED junction temperature feedback to reduce current before thermal shutdown (150°C), extending LED lifetime and reliability. |
| Pass-mode operation above VLED + VHR | Eliminates switching losses when input voltage exceeds LED forward voltage plus headroom-improving efficiency to >85% at 100 mA torch. |
| Hardware STROBE and TORCH/TEMP inputs | Supports deterministic, low-latency flash/torch activation independent of I²C bus availability-essential for shutter-synced photography. |
Applications
| Smartphone Dual-LED Camera Flash | Digital Still Camera Auxiliary Lighting |
|---|---|
Use Scenario: Simultaneous illumination from warm and cool white LEDs during photo capture to achieve accurate color rendering under mixed lighting. IC Role / Device Role / Timing Role: Dual high-side current source providing independently programmable 360 mA torch and 1.5 A flash currents with synchronized ramp timing. Use Value: Enables real-time white balance correction by precisely controlling relative intensity of two LEDs-eliminating post-processing artifacts. | Use Scenario: Compact DSLR or mirrorless camera using auxiliary flash for fill light in studio or outdoor portrait sessions. IC Role / Device Role / Timing Role: High-efficiency boost driver delivering regulated 1.5 A peak current to xenon-compatible white LEDs with programmable 1.6 s timeout. Use Value: Extends battery life via >85% torch-mode efficiency and supports burst flash sequences without thermal throttling. |
| Emergency Strobe Notification System | Barcode Scanner Illumination Module |
Use Scenario: Life-safety device requiring certified visual alert with adjustable flash duration and intensity for hearing-impaired users. IC Role / Device Role / Timing Role: Programmable flash timeout (40–1600 ms) and current scaling via I²C or hardware STROBE for compliance with EN 60601-1-8. Use Value: Meets regulatory strobe cadence requirements while maintaining consistent lumen output across battery discharge cycles. | Use Scenario: Industrial handheld scanner needing uniform LED illumination across varying ambient light conditions and scan distances. IC Role / Device Role / Timing Role: Torch-mode driver with NTC-based thermal derating to sustain 360 mA output during continuous scanning without LED degradation. Use Value: Ensures reliable decode performance by stabilizing LED flux over temperature-reducing false-read rates in hot environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-LED flash driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3644YFFR | Lower max torch current (179 mA vs. 360 mA); flash timeout limited to 400 ms. | Suitable for cost-sensitive single-LED or low-power torch applications; not recommended for dual-LED high-lumen video lighting. | Select LM3644YFFR only when thermal budget or peak luminance requirements are relaxed. |
| RT8546GQW | Single-channel 1.5-A flash driver; no dual-current-source architecture or NTC monitoring. | Requires two ICs for dual-LED control; lacks hardware TORCH/TEMP pin and IVFM functionality. | Choose RT8546GQW only for legacy single-LED designs where board area and feature count are secondary to BOM cost. |
Compared with LM3644YFFR and RT8546GQW, LM3644TTYFFR uniquely delivers dual-channel 360 mA torch capability with integrated thermal sensing and adaptive low-VIN current scaling-making it the only option for compact, thermally constrained dual-LED camera modules requiring full-feature flash/torch coexistence.
Availability
LM3644TTYFFR is available at Aetrix Electronics and suitable for smartphone camera modules, industrial barcode scanners, and emergency strobe lighting requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LM3644TTYFFR 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 mobile imaging systems requiring high-efficiency, dual-LED flash/torch drivers with minimal footprint, thermal intelligence, and robust battery-voltage adaptability.
FAQ
What is the maximum torch current supported by the LM3644TTYFFR?
The LM3644TTYFFR supports a maximum torch current of 360 mA per channel (LED1 and LED2). This is confirmed in the Device Comparison Table and Electrical Characteristics section of the datasheet, distinguishing it from the standard LM3644YFFR (179 mA). The 360 mA rating applies across the full operating temperature range (−40°C to +85°C) with ±10% accuracy and requires proper thermal design using the DSBGA-12 package's low RθJB (40.0°C/W).
Does the LM3644TTYFFR support hardware-triggered flash without I²C communication?
Yes, the LM3644TTYFFR supports fully autonomous hardware-triggered flash via the STROBE pin (B2), which is active-high with an internal 300 kΩ pulldown resistor. Asserting STROBE high initiates the programmed flash sequence-including current ramp-up and timeout-without any I²C interaction. This enables sub-microsecond latency for shutter-synchronized photography, a core design requirement validated in the Functional Block Diagram and Pin Functions table.
How does the LM3644TTYFFR handle thermal management during sustained torch operation?
The LM3644TTYFFR implements dual-layer thermal protection: (1) an internal thermal shutdown circuit engaging at TJ = 150°C (typical), and (2) user-configurable NTC-based current derating via the TORCH/TEMP pin (C3). When an NTC thermistor is connected, the internal comparator monitors voltage drop across it and scales down torch current before reaching critical junction temperature-preserving LED lifetime and enabling continuous 360 mA operation within defined thermal limits.
What is the purpose of the TX pin on the LM3644TTYFFR, and how is it used?
The TX pin (D2) on the LM3644TTYFFR is a configurable dual-polarity input designed to synchronize flash pulses with RF power amplifier activity. During high-current RF transmission (e.g., LTE/Wi-Fi burst), asserting TX interrupts the ongoing flash sequence to prevent battery voltage droop. Its internal 300 kΩ pulldown ensures safe default behavior, and polarity configuration is set via register bits-enabling compatibility with both active-high and active-low PA control signals in modern smartphone baseband architectures.
Can the LM3644TTYFFR operate in pass mode, and what are the benefits?
Yes, the LM3644TTYFFR automatically enters pass mode when the input voltage exceeds the LED forward voltage plus required headroom (VHR = 270 mV at 360 mA). In this state, the internal PMOS switch turns on continuously, bypassing the boost converter. This eliminates switching losses and improves efficiency to >85% in torch mode at 100 mA-critical for extending battery life in always-on illumination applications such as video recording or emergency signaling.
LM3644TTYFFR 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
LM3644TTYFFR FAQ
1.How can I place an order for LM3644TTYFFR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3644TTYFFR 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 LM3644TTYFFR reliable?
The price and inventory of LM3644TTYFFR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3644TTYFFR is usually 5 days.
3.What payment methods are accepted for LM3644TTYFFR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3644TTYFFR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3644TTYFFR?
LM3644TTYFFR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3644TTYFFR 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 LM3644TTYFFR?
For technical support, including LM3644TTYFFR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3644TTYFFR requirements.
6.How does Aetrix verify that LM3644TTYFFR is sourced from the original manufacturer or authorized distributors?
All LM3644TTYFFR 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 LM3644TTYFFR meets industry standards.
7.What is the process for return or replacement of LM3644TTYFFR?
All LM3644TTYFFR units undergo pre-shipment inspection (PSI). If there is an issue with LM3644TTYFFR, 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 LM3644TTYFFR part is unused and in its original packaging.
Return procedure for LM3644TTYFFR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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