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Texas Instruments LM3643YFFR
- Part No.:
- LM3643YFFR
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 12-UFBGA, DSBGA
- Datasheet:
-
LM3643YFFR.pdf
- Description:
- IC LED DRVR RGLTR I2C 12DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:5,128
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Product details
Overview
LM3643YFFR from Texas Instruments is a synchronous boost dual LED flash driver IC with two independent 1.5-A high-side current sources, 2-MHz/4-MHz programmable switching frequency, I²C-compatible interface (0x63), and integrated thermal/NTC monitoring for smartphone camera flash systems.
For engineers reviewing the LM3643YFFR datasheet, LM3643YFFR pinout, LM3643YFFR application, or LM3643YFFR equivalent, key selection criteria include total 1.5-A combined LED current capability, grounded-cathode LED operation for thermal management, hardware strobe/torch enable pins, IVFM-based low-battery flash current scaling, and DSBGA-12 package compatibility with space-constrained mobile designs.
Technical Context
The LM3643YFFR integrates a fixed-frequency current-mode PWM boost converter with adaptive pass-mode operation: it operates in non-switching pass mode when VIN ≥ VLED + VHR (158–290 mV), switching to 2-MHz or 4-MHz boost mode only when headroom is insufficient. Its dual high-side current sources regulate independently via 128-step I²C-programmable flash (10.9 mA–1.5 A) and torch (0.977 mA–179 mA) currents.
Hardware control inputs-STROBE (flash trigger), TORCH/TEMP (torch enable or NTC thermistor input), TX (PA sync interrupt), and HWEN (hard reset)-feature internal 300-kΩ pulldowns. The device implements IVFM-based dynamic flash current reduction below 2.9 V input and thermal shutdown at 150°C with hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input voltage range | 2.5 V to 5.5 V - supports single-cell Li-ion battery operation across full discharge curve. |
| Total LED current | 1.5 A max (ILED1 + ILED2) - enables high-luminance dual-LED flash without external current combining. |
| Switching frequency | 2 MHz or 4 MHz - allows use of ultra-small 1-µH inductors and 10-µF ceramic output capacitors. |
| Current accuracy | ±7% flash / ±10% torch - ensures consistent brightness across temperature (−40°C to +85°C). |
| I²C address | 0x63 - enables coexistence with LM3643A (0x67) on same bus for multi-flash configurations. |
| Thermal protection | Junction shutdown at 150°C, recovery at 135°C - prevents permanent damage during sustained high-current operation. |
| Package | DSBGA-12, 1.69 mm × 1.31 mm - ultra-compact footprint for front-camera module integration. |
Pinout & Package
LM3643YFFR uses a 12-pin DSBGA package (1.69 mm × 1.31 mm, 0.4-mm pitch) with bottom-soldered balls. Thermal performance is optimized via exposed die pad connected to PCB ground plane (RθJA = 67.8°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (A1) | Ground reference | Primary return path for boost converter, LED currents, and logic; must be low-impedance connection to PCB ground plane. |
| IN (A2) | Input supply | Connects to 2.5–5.5 V source; requires ≥10 µF ceramic bypass capacitor to GND for stability and transient response. |
| SDA (A3) | I²C data line | Open-drain bidirectional interface for register read/write; requires external pull-up to VIN or IOVDD (1.8–5.5 V). |
| SW (B1) | Internal switch node | Connection point between NMOS/PMOS switches; routes to external inductor and must be minimized for EMI and efficiency. |
| STROBE (B2) | Hardware flash trigger | Active-high signal; initiates flash sequence immediately; internal 300-kΩ pulldown ensures safe default-off state. |
| SCL (B3) | I²C clock line | Open-drain input; synchronizes I²C communication; requires external pull-up matching SDA. |
| OUT (C1) | Boost converter output | Drives LED anodes; connects to 10-µF ceramic capacitor to GND and LED1/LED2 anodes via low-inductance traces. |
| HWEN (C2) | Hardware enable/reset | Active-low; forces device reset and register initialization when pulled to GND; internal 300-kΩ pulldown. |
| TORCH/TEMP (C3) | Torch enable or NTC input | Configurable: high = torch mode activation; or analog input for external NTC thermistor to scale back current at high temp. |
| LED2 (D1) | High-side LED2 current source | Sinks current from LED2 anode to GND; supports up to 1.5 A; grounded-cathode topology improves thermal dissipation. |
| TX (D2) | PA synchronization input | Interrupts flash pulse by forcing torch-level current during RF transmit events; internal 300-kΩ pulldown. |
| LED1 (D3) | High-side LED1 current source | Sinks current from LED1 anode to GND; independently programmable; shares 1.5-A total current budget with LED2. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 128-step current sources | Enables precise ratio control (e.g., 950 mA + 550 mA) or asymmetric flash/torch profiles without external components. |
| Adaptive pass/boost mode switching | Eliminates switching losses at high input voltage, improving efficiency >85% in torch mode (100 mA) and flash mode (1 A). |
| Input Voltage Flash Monitor (IVFM) | Adjustable 2.9–3.6 V threshold with hysteresis reduces flash current during battery sag, preventing system brownout. |
| Hardware strobe & torch enable | Enables instant flash triggering and torch activation without I²C latency-critical for camera shutter synchronization. |
| NTC thermistor interface | Direct analog sensing on TORCH/TEMP pin allows real-time thermal derating of LED current to protect optics and housing. |
| RF power amplifier sync (TX) | Reduces peak battery current during cellular transmission by dynamically throttling flash current, avoiding PMIC overload. |
Applications
| Smartphone Dual-LED Flash | Front-Facing Camera Torch |
|---|---|
Use Scenario: High-intensity rear-facing flash for low-light photography with dual white LEDs. IC Role / Device Role / Timing Role: Dual high-side current source driving LED1 and LED2 in parallel with synchronized ramp-up and IVFM-based current scaling. Use Value: Delivers 1.5 A total flash current with <±7% accuracy across −40°C to +85°C, enabling consistent exposure in varying ambient conditions. |
Use Scenario: Always-on video call illumination using front camera with single or dual LEDs. IC Role / Device Role / Timing Role: Torch-mode current regulator with 128-step programmability (0.977–179 mA) and hardware TORCH/TEMP enable. Use Value: Provides stable, flicker-free illumination at low power (<10 µA standby), extending battery life during prolonged video sessions. |
| Tablet Camera Module | Automotive Interior Camera |
Use Scenario: Wide-angle tablet rear camera requiring uniform illumination across large sensor area. IC Role / Device Role / Timing Role: Independent current control per LED leg (LED1/LED2) with matched ramp timing and thermal foldback. Use Value: Enables balanced luminance distribution and automatic current reduction if NTC detects lens housing overheating. |
Use Scenario: Driver-monitoring or cabin occupancy detection system with IR-capable flash. IC Role / Device Role / Timing Role: IR Mode operation with STROBE-controlled on/off pulses and pass-mode efficiency for 850-nm LEDs. Use Value: Supports rapid, low-latency IR strobing synchronized to image capture without boosting overhead, minimizing EMI in safety-critical systems. |
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 |
|---|---|---|---|
| LM3643AYFFR | I²C address 0x67 (vs. 0x63); identical electrical specs and pinout. | Enables dual LM3643 devices on same I²C bus for triple+ LED configurations. | Select when expanding beyond two LEDs or requiring separate flash/torch control domains. |
| LM3603YFFR | Single-channel 1.5-A flash driver; no LED2 output; smaller 8-pin DSBGA (1.36 mm × 0.96 mm). | Lacks dual-current flexibility and TX/NTC features; optimized for cost-sensitive single-LED modules. | Choose for space-constrained single-LED designs where dual control and thermal monitoring are unnecessary. |
Compared with LM3643AYFFR, the LM3643YFFR provides identical performance but enables simpler I²C arbitration in single-device systems; versus LM3603YFFR, it adds critical dual-LED coordination, PA sync, and thermal safety-justifying its use in flagship smartphone cameras.
Availability
LM3643YFFR is available at Aetrix Electronics and suitable for smartphone camera modules, front-facing torch systems, tablet imaging subsystems, and automotive interior vision applications requiring stable component supply and long-term production continuity.
Supply support for LM3643YFFR 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 over 50 years of innovation in precision analog ICs.
The LM3643YFFR belongs to TI's mobile LED driver product line, engineered specifically for high-efficiency, thermally robust flash and torch illumination in space- and power-constrained portable imaging systems.
FAQ
What is the I²C address of the LM3643YFFR?
The LM3643YFFR has a fixed I²C slave address of 0x63 (7-bit). This distinguishes it from the LM3643AYFFR (0x67), allowing both devices to coexist on the same I²C bus. The address is hardwired and not software-configurable. All register reads and writes for the LM3643YFFR must target 0x63 to ensure correct communication and avoid bus conflicts in multi-device camera modules.
How does the LM3643YFFR handle low input voltage during flash operation?
The LM3643YFFR implements Input Voltage Flash Monitor (IVFM) to dynamically scale flash current when VIN drops below a programmable threshold (2.9–3.6 V). When triggered, it reduces LED current to prevent system brownout-critical during high-current battery discharge. This feature is configurable via registers and operates independently of I²C activity, ensuring real-time response. The LM3643YFFR maintains regulation down to 2.5 V input.
Can the LM3643YFFR drive LEDs in grounded-cathode configuration?
Yes, the LM3643YFFR uses high-side current sources on LED1 and LED2 pins, enabling direct connection of LED cathodes to GND-a grounded-cathode topology. This configuration improves thermal dissipation by routing heat away from the IC die through the PCB ground plane, enhances layout simplicity, and avoids reverse-voltage stress on LED junctions. It is explicitly supported and recommended in the LM3643YFFR datasheet.
What is the purpose of the TX pin on the LM3643YFFR?
The TX pin on the LM3643YFFR is a hardware input for synchronizing flash pulses with RF power amplifier transmit events. When asserted high during a flash sequence, it forces immediate transition to programmed torch current-reducing peak battery demand and preventing PMIC overload. Upon TX deassertion, flash resumes. This feature is essential for maintaining cellular compliance and system stability in smartphones during simultaneous flash and LTE/Wi-Fi transmission.
Does the LM3643YFFR support thermal protection using an external NTC thermistor?
Yes, the LM3643YFFR supports NTC thermistor monitoring via the TORCH/TEMP pin. When configured as an analog input, it measures voltage across an external NTC-resistor divider to detect temperature rise. If the sensed voltage crosses a programmable threshold, the device automatically scales back LED current to prevent thermal damage to lenses or housing. This closed-loop thermal management is fully integrated and requires no external ADC or processor intervention.
LM3643YFFR 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:
- 750mA
- 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
LM3643YFFR FAQ
1.How can I place an order for LM3643YFFR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3643YFFR 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 LM3643YFFR reliable?
The price and inventory of LM3643YFFR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3643YFFR is usually 5 days.
3.What payment methods are accepted for LM3643YFFR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3643YFFR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3643YFFR?
LM3643YFFR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3643YFFR 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 LM3643YFFR?
For technical support, including LM3643YFFR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3643YFFR requirements.
6.How does Aetrix verify that LM3643YFFR is sourced from the original manufacturer or authorized distributors?
All LM3643YFFR 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 LM3643YFFR meets industry standards.
7.What is the process for return or replacement of LM3643YFFR?
All LM3643YFFR units undergo pre-shipment inspection (PSI). If there is an issue with LM3643YFFR, 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 LM3643YFFR part is unused and in its original packaging.
Return procedure for LM3643YFFR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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