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Texas Instruments LP3944ISQ
- Part No.:
- LP3944ISQ
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP3944ISQ.pdf
- Description:
- IC LED DRIVER PS I2C 25MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,739
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Product details
Overview
LP3944ISQ from Texas Instruments is an 8-channel I²C-compatible LED driver IC with open-drain outputs, internal precision oscillator, and dual programmable PWM dimming (DIM0/DIM1) for RGB/white/blue LEDs. It supports 25 mA per channel, 200 mA total package sink current, and operates from 2.3 V to 5.5 V - used in cellular phone indicator lighting, portable device status displays, and toy lighting effects.
For engineers reviewing the LP3944ISQ datasheet, LP3944ISQ pinout, LP3944ISQ application, or LP3944ISQ equivalent, key selection criteria include its WQFN-24 package, SMBus/I²C interface compliance, dual-dimming-rate capability (6.25 ms–1.6 s), GPIO-expansion functionality on unused LED pins, and active-low reset with internal POR.
Technical Context
The LP3944ISQ integrates a precision internal oscillator (no external crystal required), two prescaler registers (PSC0/PSC1), and two PWM registers (PWM0/PWM1) to independently configure dimming period and duty cycle for two distinct LED groups. Each of the eight LED outputs is individually assignable to ON/OFF/DIM0/DIM1 states via selector registers LS0/LS1.
It implements standard SMBus v1.1 / I²C-compatible communication (400 kHz max clock), supports auto-increment addressing across nine registers (0x00–0x09), and features hardware reset (RST#) with 10 ns minimum pulse width. Unused LED pins function as general-purpose open-drain I/Os with 25 mA sink capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDD Range | 2.3 V to 5.5 V - compatible with single Li-ion, USB 5 V, or 3.3 V logic rails without level-shifting. |
| LED Sink Current | 25 mA per pin, 200 mA total - sufficient for driving high-brightness indicator LEDs directly. |
| Dimming Period Range | 6.25 ms to 1.6 s (160 Hz to 0.625 Hz) - enables slow pulsing, fast blinking, and smooth breathing effects. |
| I²C Clock Frequency | Up to 400 kHz - supports standard-mode I²C bus timing without requiring high-speed mode hardware. |
| Operating Temp | −40°C to +85°C - qualified for industrial and consumer portable equipment environments. |
| Thermal Resistance θJA | 37°C/W (WQFN-24) - requires thermal pad soldering to PCB for reliable power dissipation at full load. |
| Reset Threshold VPOR | 1.8 V to 1.96 V - ensures clean initialization during brown-out or battery ramp-up conditions. |
Pinout & Package
LP3944ISQ is housed in a 4 mm × 4 mm, 0.8 mm max height, thermally enhanced WQFN-24 package (TI package code RTW0024A) with exposed thermal pad. Pin 1 is located in quadrant Q1; the thermal pad must be soldered to PCB ground for thermal and mechanical reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED0–LED7 | Open-drain LED driver outputs | Each sinks up to 25 mA; configured via LS0/LS1 register bits to ON/OFF/DIM0/DIM1 states. |
| GND | Ground reference | Primary return path for LED current and logic; connects to exposed thermal pad. |
| RST# | Active-low hardware reset input | Pulls all registers to default state when held low ≥10 ns; internally pulled up. |
| SCL / SDA | I²C serial clock/data lines | Support 400 kHz operation; require external pull-ups; compliant with SMBus v1.1 timing. |
| VDD | Power supply input | Supplies internal oscillator, logic, and output drivers; decoupling capacitor required near pin. |
| A0–A2 | I²C slave address inputs | Set 3 LSBs of 7-bit address (base 0x60); allow up to 8 devices on same bus. |
| NC (Pins 10–17) | No-connect terminals | Internally unconnected; must be left floating or tied to GND - no routing or loading required. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent PWM dimming | Two fully configurable dimming rates (DIM0/DIM1) enable synchronized multi-color animation without host CPU intervention. |
| Internal precision oscillator | Eliminates need for external timing components; provides stable LED timing across voltage and temperature. |
| GPIO expansion capability | Unused LED pins operate as general-purpose open-drain I/Os - extends microcontroller I/O count without added ICs. |
| Low quiescent current | 350–550 µA typical supply current (no load) - critical for battery-powered portable applications. |
| Power-on reset & active-low RST# | Ensures known initial state at power-up and allows synchronous system-level reset coordination. |
Applications
| Cellular Phone Indicator Lighting | Portable Digital Camera Status Display |
|---|---|
Use Scenario: Driving RGB LEDs for call alert, charging status, and notification pulses in compact smartphone front bezels. IC Role / Device Role / Timing Role: LED driver with I²C-controlled dimming and color sequencing; replaces discrete transistor arrays and reduces MCU GPIO usage. Use Value: Enables rich visual feedback using only two MCU pins (SCL/SDA), while internal oscillator and dual PWM eliminate timing firmware overhead. |
Use Scenario: Controlling white/blue LED indicators for power-on, recording, low-battery, and SD card activity in handheld cameras. IC Role / Device Role / Timing Role: Low-power LED driver with programmable blink rates and brightness; interfaces directly to baseband controller over shared I²C bus. Use Value: Reduces BOM count by consolidating 8 LED controls into one IC; supports rapid design iteration via register configuration instead of hardware changes. |
| Toy Lighting & Animation Effects | Industrial Handheld Device UI |
Use Scenario: Creating dynamic light patterns (chasing, fading, strobing) in children's electronic toys powered by AA/AAA batteries. IC Role / Device Role / Timing Role: Autonomous LED animator with built-in timing engine; executes programmed sequences without continuous host polling. Use Value: Extends battery life by minimizing I²C traffic - only one command needed to start/stop a preconfigured dimming sequence. |
Use Scenario: Providing status indication (power, error, connectivity) on ruggedized handheld test equipment operating in −40°C to +85°C ambient. IC Role / Device Role / Timing Role: Industrial-grade LED driver with extended temperature range and robust ESD protection (2 kV HBM). Use Value: Ensures reliable visual feedback under harsh conditions; WQFN thermal pad improves long-term reliability in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC59116IPWR | 16-channel I²C LED driver; higher channel count but no internal oscillator - requires external clock or MCU timing. | Better suited for high-channel-count panels; lacks autonomous dimming - all PWM timing generated externally. | Choose TLC59116IPWR when >8 channels or higher current (100 mA/channel) are required; avoid if autonomous dimming or space-constrained layout is critical. |
| PCA9635D,118 | 16-channel I²C LED driver with internal oscillator and 256-step brightness control; supports grayscale, not just on/off/dim. | Enables smooth intensity transitions and color mixing; larger footprint (HTSSOP-28) and higher IQ than LP3944ISQ. | Choose PCA9635D,118 for applications needing precise grayscale control or RGB color blending; LP3944ISQ remains optimal for simple indicator blinking with minimal board area. |
Compared with TLC59116IPWR and PCA9635D,118, the LP3944ISQ delivers the smallest footprint (WQFN-24), lowest quiescent current, and simplest register map for basic 8-LED indicator use - making it ideal where cost, size, and firmware simplicity are prioritized over grayscale or channel count.
Availability
LP3944ISQ is available at Aetrix Electronics and suitable for cellular phone accessories, portable digital cameras, and industrial handheld UIs requiring stable component supply, consistent WQFN-24 packaging, and long-lifecycle availability.
Supply support for LP3944ISQ 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 experience in precision analog IC design and automotive-grade reliability validation.
The LP3944ISQ belongs to TI's legacy LED driver portfolio designed specifically for low-pin-count, low-power indicator lighting in space-constrained portable electronics - emphasizing integration, ease of I²C control, and autonomous timing.
FAQ
What is the maximum sink current per LED channel on the LP3944ISQ?
The LP3944ISQ supports up to 25 mA per LED output pin (LED0–LED7), with a total package limit of 200 mA. This rating is specified across the full operating temperature range (−40°C to +85°C) and requires proper PCB thermal design - especially soldering the exposed thermal pad to a ground plane. Exceeding 25 mA per pin risks output stage degradation and violates absolute maximum ratings.
Does the LP3944ISQ require an external crystal or RC network for timing?
No, the LP3944ISQ does not require any external timing components. It contains a fully integrated precision oscillator that generates all internal timing signals for PWM dimming and register operations. This eliminates BOM cost, board space, and calibration effort - enabling immediate dimming functionality after I²C configuration without additional circuitry.
Can unused LED pins on the LP3944ISQ be repurposed as general-purpose I/Os?
Yes, unused LED pins (LED0–LED7) on the LP3944ISQ can be configured as general-purpose open-drain I/Os by setting their corresponding bits in the LS0/LS1 selector registers to "00" (Hi-Z). Each functions as a 25 mA sink-capable I/O, allowing microcontroller GPIO expansion without adding discrete transistors or shift registers - verified in the LP3944ISQ datasheet Section 8.3.
What I²C address options are supported by the LP3944ISQ?
The LP3944ISQ supports seven user-configurable I²C slave addresses via address pins A0, A1, and A2. With A2–A0 grounded, the base address is 0x60; each pin pulled high increments the address by 1, yielding addresses 0x60 through 0x67. This allows up to eight LP3944ISQ devices on a single I²C bus - confirmed in Register Map Table 1 and Figure 6 of the official SNVS264A datasheet.
Is the LP3944ISQ RoHS-compliant and lead-free?
Yes, the LP3944ISQ is RoHS-compliant and lead-free. Per TI's Packaging Information Addendum, the LP3944ISQ/NOPB.A variant carries "Yes" for RoHS and uses Sn (tin) lead finish. It meets JEDEC MSL Level-3 moisture sensitivity requirements and is rated for peak reflow at 260°C - suitable for standard lead-free PCB assembly processes without special handling.
LP3944ISQ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Power Switch
- Topology:
- Shift Register
- Internal Switch(s):
- Yes
- Number of Outputs:
- 8
- Voltage - Supply (Min):
- 2.3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- -
- Current - Output / Channel:
- 25mA
- Frequency:
- -
- Dimming:
- I2C, SMBus
- Applications:
- Camera Flash
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x4)
LP3944ISQ FAQ
1.How can I place an order for LP3944ISQ through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3944ISQ 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 LP3944ISQ reliable?
The price and inventory of LP3944ISQ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3944ISQ is usually 5 days.
3.What payment methods are accepted for LP3944ISQ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3944ISQ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3944ISQ?
LP3944ISQ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3944ISQ 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 LP3944ISQ?
For technical support, including LP3944ISQ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3944ISQ requirements.
6.How does Aetrix verify that LP3944ISQ is sourced from the original manufacturer or authorized distributors?
All LP3944ISQ 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 LP3944ISQ meets industry standards.
7.What is the process for return or replacement of LP3944ISQ?
All LP3944ISQ units undergo pre-shipment inspection (PSI). If there is an issue with LP3944ISQ, 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 LP3944ISQ part is unused and in its original packaging.
Return procedure for LP3944ISQ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LP3944ISQ Tags
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