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Texas Instruments LP3944ISQX/NOPB
- Part No.:
- LP3944ISQX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP3944ISQX/NOPB.pdf
- Description:
- IC LED DRIVER PS I2C 25MA 24WQFN
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LP3944ISQX/NOPB 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). It delivers up to 25 mA per channel, supports RGB/white/blue LED control, and operates from 2.3 V to 5.5 V - used in cellular phone indicator lighting, accessory status feedback, and portable device fun-light effects.
For engineers reviewing the LP3944ISQX/NOPB datasheet, LP3944ISQX/NOPB pinout, LP3944ISQX/NOPB application, or LP3944ISQX/NOPB equivalent, key selection considerations include I²C address configuration (A0–A2), dual-dimming rate flexibility (6.25 ms–1.6 s), 200 mA total package sink current limit, and WQFN-24 thermal pad layout requirements.
Technical Context
The LP3944ISQX/NOPB integrates a precision internal oscillator (no external crystal required) and two independent prescaler-PWM register pairs (PSC0/PWM0 and PSC1/PWM1) to generate two distinct dimming frequencies and duty cycles. Each of the eight LED outputs is individually configurable via selector registers (LS0/LS1) into one of four states: high-impedance (off), active-low (on), DIM0, or DIM1.
I²C communication uses standard SMBus-compatible timing (400 kHz max), with hardwired 7-bit address bits (0x60–0x67) determined by A0–A2 inputs. The device includes active-low reset (RST), power-on reset (VPOR = 1.96 V), and auto-increment register addressing for efficient multi-register writes without repeated address bytes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LED Channels | 8 independent open-drain outputs, each sinking up to 25 mA; total package limit 200 mA |
| Supply Voltage Range | 2.3 V to 5.5 V - compatible with 3.3 V and 5 V logic rails without level shifting |
| Dimming Resolution | 256-step PWM duty cycle (0%–100% in ~0.39% increments) via 8-bit PWM registers |
| Dimming Period Range | 6.25 ms to 1.6 s (160 Hz to 0.625 Hz) set by 8-bit prescaler registers (PSC0/PSC1) |
| I²C Interface | Standard-mode (400 kHz) SMBus/I²C with 7-bit address (0x60–0x67) and auto-increment support |
| Operating Temperature | −40°C to +85°C ambient - qualified for industrial portable electronics environments |
| Quiescent Current | 350–550 µA (no load); additional 2 mA standby current per LED pin held at 4.3 V |
Pinout & Package
LP3944ISQX/NOPB is housed in a 4 mm × 4 mm, 0.8 mm max height WQFN-24 package (TI package code RTW0024A) with exposed thermal pad (Pin 25) requiring PCB solder connection for thermal and mechanical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED0–LED7 (Pins 1–8) | Open-drain LED driver outputs | Sink up to 25 mA each; configured as ON/OFF/DIM0/DIM1 via LS0/LS1 registers |
| GND (Pin 9) | Ground reference | Primary return path for all LED currents and internal circuitry; connect to low-impedance ground plane |
| NC (Pins 10–17) | No-connect terminals | Internally unconnected; must be left floating or tied to GND per layout guidelines |
| RST (Pin 18) | Active-low hardware reset | Holding LOW ≥10 ns forces default state initialization; synchronous with VDD power-up POR |
| SCL (Pin 19) | I²C clock input | Accepts standard-mode (≤400 kHz) clock signals; includes internal filtering for noise suppression |
| SDA (Pin 20) | I²C bidirectional data line | Open-drain interface with internal pull-up capability; requires external pull-up resistor (typically 4.7 kΩ) |
| VDD (Pin 21) | Power supply input | 2.3–5.5 V supply; bypass with ≥1 µF ceramic capacitor close to pin |
| A0–A2 (Pins 22–24) | I²C address select inputs | Set LSBs of 7-bit slave address (0x60–0x67); logic levels define unique bus node identity |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent dimming engines | Separate PSC0/PWM0 and PSC1/PWM1 registers enable simultaneous blinking at two distinct frequencies/duty cycles |
| Integrated oscillator | Eliminates external timing components - enables full LED control with only I²C commands and VDD/GND |
| General-purpose I/O expansion | Unused LED pins function as GPIOs with programmable input/output states (Hi-Z, driven low) |
| Low bus traffic operation | After initial setup, single-byte I²C commands toggle LED states - no continuous PWM bit-banging required |
| Power-on and hardware reset | Guaranteed initialization on power-up (VPOR = 1.96 V) and deterministic recovery via RST pin assertion |
Applications
| Cellular Phone Indicator Lighting | Portable Digital Camera Status Feedback |
|---|---|
|
Use Scenario: Flashing blue/RGB LEDs indicate incoming call, message, or charging status on feature phones and early smartphones. IC Role / Device Role / Timing Role: LP3944ISQX/NOPB acts as autonomous LED sequencer - executing preprogrammed blink patterns without CPU intervention. Use Value: Reduces baseband processor I/O load and I²C bus bandwidth usage while enabling rich visual feedback with minimal firmware overhead. |
Use Scenario: Multi-color LED indicators show battery level, recording mode, focus lock, or error conditions on compact digital cameras. IC Role / Device Role / Timing Role: LP3944ISQX/NOPB serves as dedicated status light controller - driving white/RGB LEDs with synchronized dimming rates. Use Value: Enables smooth, consistent brightness transitions across multiple LEDs using internal PWM timing - eliminating visible flicker or timing skew. |
| Toys and Consumer Electronics Fun Lights | Industrial Handheld Device UI Indicators |
|
Use Scenario: Animated LED patterns (chasing, pulsing, color cycling) enhance user engagement in electronic toys and novelty gadgets. IC Role / Device Role / Timing Role: LP3944ISQX/NOPB functions as embedded light engine - generating complex sequences via two independent dimming channels. Use Value: Supports creative lighting effects with zero real-time CPU involvement - freeing microcontroller resources for core functionality. |
Use Scenario: High-visibility status LEDs signal operational mode (e.g., scan active, Bluetooth connected, low battery) on rugged handheld scanners or meters. IC Role / Device Role / Timing Role: LP3944ISQX/NOPB provides robust, low-power LED drive with ESD-hardened I/O (2 kV HBM) suitable for field-deployed equipment. Use Value: Ensures reliable visual indication under variable temperature (−40°C to +85°C) and noisy electrical environments without external protection. |
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 with constant-current sinks (max 120 mA/channel), no internal oscillator, requires external clock for PWM | Higher channel count and precision current regulation; suited for display backlight or uniform illumination, not fun-light sequencing | Choose TLC59116IPWR when precise current matching across LEDs is critical and higher channel density justifies added complexity. |
| PCA9635PW | 16-channel I²C LED driver with 12-bit PWM resolution, integrated oscillator, but no dual-dimming-rate architecture | Lacks independent DIM0/DIM1 registers - all outputs share same frequency/duty cycle unless software-managed via register writes | Choose PCA9635PW when fine-grained brightness control (0.024% steps) is prioritized over independent multi-pattern execution. |
Compared with TLC59116IPWR and PCA9635PW, LP3944ISQX/NOPB uniquely balances autonomous dual-pattern execution, minimal external component count, and compact 24-pin WQFN packaging - making it optimal for cost-sensitive, space-constrained portable devices needing expressive LED behavior.
Availability
LP3944ISQX/NOPB is available at Aetrix Electronics and suitable for cellular phone accessories, portable camera UIs, consumer toy lighting, and industrial handheld indicator systems requiring stable component supply and long-term production continuity.
Supply support for LP3944ISQX/NOPB 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 company delivering analog and embedded processing solutions, with leadership in power management, signal chain, and interface technologies.
The LP3944ISQX/NOPB belongs to TI's LED driver product line, designed specifically for low-pin-count, I²C-controlled indicator lighting in battery-powered portable electronics where autonomous dimming and minimal host intervention are essential.
FAQ
What is the maximum sink current per LED output on the LP3944ISQX/NOPB?
The LP3944ISQX/NOPB supports up to 25 mA per LED output (pins LED0–LED7), with a total package limit of 200 mA. Exceeding 25 mA on any single pin or 200 mA collectively risks thermal shutdown or parametric shift. Designers must ensure PCB copper area and thermal pad soldering meet TI's WQFN-24 layout guidelines to maintain safe junction temperatures.
Does the LP3944ISQX/NOPB require an external crystal or RC network for timing?
No, the LP3944ISQX/NOPB contains a fully integrated precision oscillator that generates all internal timing - including PWM and prescaler clocks - without external components. This eliminates BOM cost and board space for timing elements while ensuring stable dimming rates across voltage (2.3–5.5 V) and temperature (−40°C to +85°C) ranges.
How many unique I²C addresses does the LP3944ISQX/NOPB support?
The LP3944ISQX/NOPB supports eight unique 7-bit I²C slave addresses (0x60 through 0x67), selected by the logic states of address pins A0, A1, and A2. All three pins are binary inputs referenced to VDD/GND, enabling up to eight LP3944ISQX/NOPB devices on the same I²C bus without address conflict.
Can unused LED pins on the LP3944ISQX/NOPB be repurposed as general-purpose I/Os?
Yes, unused LED pins (LED0–LED7) on the LP3944ISQX/NOPB can be configured as general-purpose parallel I/Os. By setting their corresponding bits in the LS0/LS1 selector registers to "00", each pin enters high-impedance input mode; setting to "01" drives it actively low. This provides up to eight additional GPIOs without requiring a separate expander IC.
What is the function of the exposed thermal pad (Pin 25) on the LP3944ISQX/NOPB WQFN package?
The exposed thermal pad (Pin 25) on the LP3944ISQX/NOPB WQFN package is electrically connected to GND and serves dual purposes: thermal dissipation (reducing θJA to 37°C/W) and mechanical anchoring. TI requires this pad to be soldered to a solid GND plane on the PCB using a defined stencil pattern (78% solder coverage) - omission causes excessive junction temperature rise and potential reliability failure.
LP3944ISQX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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)
LP3944ISQX/NOPB FAQ
1.How can I place an order for LP3944ISQX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3944ISQX/NOPB 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 LP3944ISQX/NOPB reliable?
The price and inventory of LP3944ISQX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3944ISQX/NOPB is usually 5 days.
3.What payment methods are accepted for LP3944ISQX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3944ISQX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3944ISQX/NOPB?
LP3944ISQX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3944ISQX/NOPB 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 LP3944ISQX/NOPB?
For technical support, including LP3944ISQX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3944ISQX/NOPB requirements.
6.How does Aetrix verify that LP3944ISQX/NOPB is sourced from the original manufacturer or authorized distributors?
All LP3944ISQX/NOPB 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 LP3944ISQX/NOPB meets industry standards.
7.What is the process for return or replacement of LP3944ISQX/NOPB?
All LP3944ISQX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3944ISQX/NOPB, 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 LP3944ISQX/NOPB part is unused and in its original packaging.
Return procedure for LP3944ISQX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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