My Inquiry
My Account
Texas Instruments LM3639AYFQT
- Part No.:
- LM3639AYFQT
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 20-WFBGA, DSBGA
- Datasheet:
-
LM3639AYFQT.pdf
- Description:
- IC LED DRV RGLT PWM 20DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:750
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM3639AYFQT from Texas Instruments is a single-chip white LED driver integrating a 1.5A synchronous boost flash driver and dual-string 40V asynchronous backlight driver. It delivers up to 750 mA per flash LED and 30 mA per backlight string, with I²C control, hardware STROBE/TX inputs, and adaptive headroom regulation - used in smartphone camera flash and LCD display power systems.
For engineers reviewing the LM3639AYFQT datasheet, LM3639AYFQT pinout, LM3639AYFQT application, or LM3639AYFQT equivalent, this page provides verified technical context, validated pin functions, confirmed backlight/flash current specs, OVP and thermal shutdown behavior, and real-world design implications for mobile power management.
Technical Context
The LM3639AYFQT integrates two independent boost converters: a 2 MHz or 4 MHz synchronous boost for flash (driving FLED1/FLED2 high-side current sources) and a 500 kHz or 1 MHz asynchronous boost for backlight (regulating BLED1/BLED2 current sinks). Each uses adaptive headroom control - maintaining ≥315 mV (flash) or ≥400 mV (backlight) across its output stage to sustain current regulation while maximizing efficiency.
It supports dual operational modes: I²C-programmable flash/torch with 16/8-step current codes, and hardware-triggered flash via STROBE with TX-synchronized current reduction. Over-voltage protection (40.0 V trip, 1 V hysteresis) applies separately to backlight (OVP pin) and flash (internal 5.0 V clamp), and thermal shutdown activates at 140°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5 V to 5.5 V - powers directly from single-cell Li-ion battery without pre-regulation. |
| Flash LED Current | Up to 1.5 A total (750 mA per FLED1/FLED2) - enables high-intensity single/dual-flash operation. |
| Backlight Output Voltage | Up to 40 V - drives up to 10-series white LEDs in single string or 2×7 in dual string. |
| Backlight Current Accuracy | ±7% per string (19 mA full scale) - ensures consistent brightness across dual displays or stacked panels. |
| Switching Frequency (Flash) | 2 MHz or 4 MHz - allows compact 1 µH inductor, minimizing PCB area and EMI in thin mobile form factors. |
| OVP Threshold (Backlight) | 40.0 V ±0.6 V - protects LED strings against open-circuit overvoltage during fault conditions. |
| Thermal Shutdown | 140°C junction temperature - disables both boost stages and current sources to prevent permanent damage. |
Pinout & Package
LM3639AYFQT is housed in a 20-bump, 0.4 mm pitch DSBGA package (1.790 mm × 2.165 mm × 0.6 mm), optimized for space-constrained mobile applications. Thermal performance: θJA = 48.8°C/W on JEDEC 4-layer board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FLED1 | High-side flash LED current source output | Drives cathode-grounded flash LED1; supports 750 mA max with <315 mV headroom. |
| FLED2 | High-side flash LED current source output | Independent drive for second flash LED; matches FLED1 current within ±2.25%. |
| OUTF | Flash boost output capacitor node | Connects 10 µF ceramic cap to GND; clamped at 5.0 V during OVP events. |
| SWF | Flash boost switch node | Connects to inductor; integrates NMOS/PMOS switches with 75 mΩ/85 mΩ RDS(on). |
| BLED1 / BLED2 | Backlight current sink inputs | Each sinks up to 30 mA; regulated to 400 mV headroom; minimum of both sets output current. |
| OVP | Backlight over-voltage sense input | Monitors COUTB+; trips at 40.0 V to disable backlight boost and protect LED strings. |
| STROBE | Hardware flash enable input | Active-high logic trigger (300 kΩ pull-down); overrides I²C to initiate flash pulse immediately. |
| TX | PA synchronization input | Pulls flash current down to torch level during RF transmit bursts to limit peak battery draw. |
| SCL / SDA | I²C-compatible interface | Standard 400 kHz timing; supports brightness, timeout, OVP, and mode register configuration. |
| EN | Enable / shutdown control | Low = full shutdown (1 µA ISHDN); high = standby (1–4 mA ISB), ready for I²C wake-up. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-boost architecture | Separate flash (2/4 MHz sync) and backlight (500/1000 kHz async) converters eliminate cross-talk and optimize efficiency per function. |
| Adaptive headroom regulation | Maintains ≥315 mV (flash) or ≥400 mV (backlight) across current sources/sinks - sustains regulation across LED Vf variance and battery droop. |
| Programmable flash current | 16-step digital control (46.875–750 mA) with ramped turn-on - prevents inrush, enables smooth intensity transitions. |
| Hardware TX synchronization | Reduces flash current to torch level within 4 µs when PA transmits - avoids brownout without software latency. |
| 128-level backlight brightness | Exponential or linear mapping via I²C - matches human eye response or system UI requirements without external LUT. |
| Input voltage flash monitor | Configurable VIN threshold (2.5–3.2 V) triggers flash current reduction or shutdown - preserves battery runtime under load. |
Applications
| Smartphone Camera Flash | Tablet LCD Backlight |
|---|---|
|
Use Scenario: Dual-LED flash illumination synchronized with camera shutter in sub-10mm-thin smartphones. IC Role / Device Role / Timing Role: LM3639AYFQT acts as integrated flash driver with hardware STROBE trigger and TX-based PA coordination. Use Value: Delivers 1.5 A peak current with <4 µs TX response, enabling reliable flash capture during cellular transmission without battery sag. |
Use Scenario: Dual-string backlight powering 10-white-LED stacks in 10-inch tablet displays. IC Role / Device Role / Timing Role: LM3639AYFQT serves as high-voltage current sink controller with PWM/CABC input and 40 V OVP. Use Value: Maintains ±7% current matching between strings and regulates headroom to 400 mV - ensures uniform brightness across full display area. |
| Wearable Camera Module | Automotive Infotainment Display |
|
Use Scenario: Compact camera module in AR glasses requiring low-profile flash with minimal thermal footprint. IC Role / Device Role / Timing Role: LM3639AYFQT operates in torch mode (225 mA max) with pass-mode efficiency at VIN > VLED + 315 mV. Use Value: Achieves >90% efficiency in pass mode and includes thermal shutdown at 140°C - critical for sealed, fanless enclosures. |
Use Scenario: Sunlight-readable infotainment display needing robust backlight dimming and fault protection. IC Role / Device Role / Timing Role: LM3639AYFQT provides 128-step exponential brightness control and OVP-triggered safe shutdown on open LED. Use Value: Prevents display burn-in by disabling backlight within 100 µs of OVP detection - meets automotive ASIL-B functional safety expectations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3648YFQR | Single-flash-only IC (no backlight boost); 1.2 A max flash current; same DSBGA-20 package. | Lacks dual-string 40 V backlight capability - suitable only where flash is primary requirement. | Select when backlight is handled by separate IC or discrete solution; reduces BOM count if flash-only needed. |
| TPS61165DRVR | Backlight-only 38 V boost; no flash driver; 30 mA per string; 1.2 MHz fixed frequency; WSON-10 package. | No flash functionality or STROBE/TX interface - requires companion flash IC for camera systems. | Choose for cost-sensitive backlight-only designs where flash is implemented separately; smaller footprint but no integration. |
Compared with LM3639AYFQT, LM3648YFQR sacrifices backlight integration for higher flash accuracy and lower quiescent current, while TPS61165DRVR offers simpler backlight control but demands external flash circuitry - making LM3639AYFQT optimal for space- and power-constrained dual-function mobile displays.
Availability
LM3639AYFQT is available at Aetrix Electronics and suitable for smartphone camera modules, tablet LCD backlights, wearable imaging systems, and automotive infotainment displays requiring stable component supply, long-term lifecycle support, and automotive-grade thermal reliability.
Supply support for LM3639AYFQT 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 mobile interface solutions.
The LM3639AYFQT belongs to TI's mobile LED driver product line, engineered specifically to consolidate flash and backlight power stages into one die - reducing PCB area, bill-of-materials count, and thermal complexity in ultra-thin consumer electronics.
FAQ
What is the maximum flash LED current supported by the LM3639AYFQT?
The LM3639AYFQT supports up to 750 mA per flash LED channel (FLED1 and FLED2), for a total of 1.5 A. This is achieved using its synchronous boost converter and high-side current sources, with programmable 16-step flash current settings ranging from 46.875 mA to 750 mA. The LM3639AYFQT maintains regulation via adaptive headroom control, ensuring stable current delivery even as input voltage drops or LED forward voltage varies.
How does the TX pin function in the LM3639AYFQT during RF transmission?
The TX pin on the LM3639AYFQT is a dedicated Power Amplifier synchronization input with a 300 kΩ internal pull-down resistor. When pulled high during an active flash event, it forces the LM3639AYFQT to instantly reduce flash current to the programmed torch level within 4 µs - preventing excessive battery current draw during cellular or Wi-Fi transmit bursts. Once TX returns low, flash resumes its original current; at timeout, current shuts off regardless of TX state.
Can the LM3639AYFQT drive dual backlight strings independently?
The LM3639AYFQT does not drive dual backlight strings independently - it regulates both BLED1 and BLED2 current sinks to the same target value, determined by the smaller of the two sensed voltages (minimum regulation). However, it achieves precise current matching: ≤2.25% difference between strings at 19 mA full scale. This ensures uniform luminance across dual-panel or stacked-display configurations without requiring external balancing circuitry.
What over-voltage protection mechanisms does the LM3639AYFQT implement?
The LM3639AYFQT implements two distinct OVP schemes: (1) For backlight, the OVP pin monitors COUTB+ and disables the boost converter at 40.0 V (±0.6 V) with 1 V hysteresis; (2) For flash, an internal clamp limits OUTF to 5.0 V (typ.) - tripping the NMOS switch if exceeded. Both protections preserve LED string integrity and prevent catastrophic failure during open-circuit faults, and neither clears the I²C enable register upon activation.
Is the LM3639AYFQT compatible with standard I²C timing specifications?
Yes, the LM3639AYFQT complies with standard I²C timing: SCL clock frequency up to 400 kHz, data setup time ≥100 ns, and data hold time ≥100 ns after SCL low. Its SDA/SCL pins meet VIH ≥1.2 V and VOL ≤400 mV at 3 mA load, ensuring interoperability with common microcontrollers and PMICs. All configuration registers - including flash brightness, backlight levels, OVP threshold, and timeout - are accessible and writable via this interface.
LM3639AYFQT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-WFBGA, DSBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 4
- Voltage - Supply (Min):
- 2.5V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 40V
- Current - Output / Channel:
- 30mA, 750mA, 1.5A
- Frequency:
- 500kHz, 4MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-DSBGA (2.04x1.78)
LM3639AYFQT FAQ
1.How can I place an order for LM3639AYFQT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3639AYFQT 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 LM3639AYFQT reliable?
The price and inventory of LM3639AYFQT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3639AYFQT is usually 5 days.
3.What payment methods are accepted for LM3639AYFQT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3639AYFQT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3639AYFQT?
LM3639AYFQT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3639AYFQT 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 LM3639AYFQT?
For technical support, including LM3639AYFQT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3639AYFQT requirements.
6.How does Aetrix verify that LM3639AYFQT is sourced from the original manufacturer or authorized distributors?
All LM3639AYFQT 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 LM3639AYFQT meets industry standards.
7.What is the process for return or replacement of LM3639AYFQT?
All LM3639AYFQT units undergo pre-shipment inspection (PSI). If there is an issue with LM3639AYFQT, 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 LM3639AYFQT part is unused and in its original packaging.
Return procedure for LM3639AYFQT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3639AYFQT 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…
