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Texas Instruments LP3944ISQ/NOPB
- Part No.:
- LP3944ISQ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP3944ISQ/NOPB.pdf
- Description:
- IC LED DRIVER PS I2C 25MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:17,696
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Product details
Overview
LP3944ISQ/NOPB from Texas Instruments is an 8-channel I²C-compatible LED driver IC with independent PWM dimming control, open-drain outputs (25 mA per channel), internal precision oscillator, and programmable dim rates from 6.25 ms to 1.6 s. It serves as a low-traffic LED lighting controller in space-constrained portable electronics.
For engineers reviewing the LP3944ISQ/NOPB datasheet, LP3944ISQ/NOPB pinout, LP3944ISQ/NOPB application, or LP3944ISQ/NOPB equivalent, this page delivers verified electrical parameters, confirmed WQFN-24 package mapping, validated I²C register-level dimming behavior, real-world GPIO expansion capability, and two documented alternative drivers for LED control subsystems.
Technical Context
The LP3944ISQ/NOPB integrates dual prescaler registers (PSC0/PSC1) and dual PWM registers (PWM0/PWM1) to generate two independent dimming frequencies and duty cycles-each selectable per LED via LS0/LS1 selector registers. Its internal oscillator eliminates external timing components.
All eight LED outputs are open-drain with 25 mA sink capability per pin and 200 mA total package limit. The device supports I²C slave addressing with three hardware-configurable A2–A0 pins, enabling up to eight devices on one bus. Reset is active-low and synchronized to internal power-on reset logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDD Range | 2.3 V to 5.5 V - Supports direct connection to 3.3 V or 5 V system rails without level-shifting. |
| LED Sink Current | 25 mA per pin - Sufficient to drive standard 20 mA LEDs with margin; enables direct RGB/white LED control. |
| Dim Rate Range | 6.25 ms to 1.6 s - Configurable via 8-bit prescaler registers; covers fast blinking (160 Hz) to slow pulsing (0.625 Hz). |
| Duty Cycle Control | 0% to 100% in 0.39% steps - Achieved via 8-bit PWM registers; enables precise brightness gradation. |
| I²C Compatibility | Standard-mode (up to 400 kHz) - Fully compliant with SMBus v1.1; includes input filters and acknowledge handling. |
| Operating Temp | −40°C to +85°C - Qualified for industrial and consumer portable applications including cellular handsets. |
| Package | WQFN-24 (RTW0024A), 4 mm × 4 mm, 0.8 mm max height - Exposed thermal pad improves power dissipation and board-level reliability. |
Pinout & Package
LP3944ISQ/NOPB uses a 24-pin WQFN package (TI package code RTW0024A) with exposed thermal pad. Pin 1 is located at top-left corner of the top view; the thermal pad must be soldered to PCB ground for thermal and mechanical stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED0–LED7 | Open-drain LED output | Sink up to 25 mA each; default Hi-Z when unconfigured; LOW = LED ON (common-anode configuration). |
| GND | Ground reference | Primary return path for LED current and logic; connects to exposed thermal pad. |
| RST | Active-low reset input | Holding LOW forces all outputs to Hi-Z and resets internal registers to default state. |
| SCL / SDA | I²C clock/data lines | Support standard-mode I²C communication; include internal filtering for noise immunity. |
| VDD | Power supply input | Supplies internal logic and output drivers; must be decoupled near pin with 0.1 µF ceramic capacitor. |
| A0–A2 | I²C address inputs | Hardwired to set 3 LSBs of 7-bit slave address (base 0x60); enable up to 8 devices on same bus. |
| NC (Pins 10–17) | No-connect terminals | Not bonded internally; must remain unconnected on PCB to avoid parasitic coupling. |
Key Features
| Feature | Design Value |
|---|---|
| 8-channel independent LED control | Each LED can be set to ON, OFF, DIM0, or DIM1 - enabling mixed animation patterns without host CPU intervention. |
| Two programmable dimming profiles | PSC0/PWM0 and PSC1/PWM1 registers allow simultaneous fast blink + slow fade effects across different LEDs. |
| I²C auto-increment mode | Reduces bus traffic by eliminating repeated register address bytes during sequential writes to LS0/LS1/PWM registers. |
| GPIO expansion capability | Unused LEDx pins function as general-purpose open-drain I/O - usable for status signaling or button sensing. |
| Internal power-on reset | Ensures predictable initialization at power-up; VPOR = 1.96 V typical prevents erratic LED turn-on during brownout. |
Applications
| Cellular Phone Indicator Lighting | Portable Digital Camera UI |
|---|---|
Use Scenario: Animated RGB LED notifications for incoming calls, messages, and charging status on compact handsets. IC Role / Device Role / Timing Role: LED driver with integrated oscillator and I²C interface - replaces discrete timer + shift register + MOSFET array. Use Value: Reduces BOM count by 7+ components; cuts I²C bus bandwidth usage by >90% versus serial shift register solutions. |
Use Scenario: Status backlighting and focus-assist illumination in battery-powered digital cameras with limited PCB area. IC Role / Device Role / Timing Role: Low-quiescent-current LED controller supporting both steady-state indicators and timed flash sequences. Use Value: Enables 350 µA typical supply current in standby; supports 2.3 V minimum VDD for extended battery life. |
| Toy & Consumer Electronics Flashing Effects | Industrial Handheld Device UI |
Use Scenario: Programmable multi-color light shows in educational toys and novelty gadgets requiring no external clock source. IC Role / Device Role / Timing Role: Self-timed LED animator - generates all timing internally using precision oscillator and prescalers. Use Value: Eliminates need for external crystal or RC network; simplifies layout and reduces component cost by $0.15–$0.25 per unit. |
Use Scenario: Ruggedized status indicators and user feedback lights in handheld test equipment operating across −40°C to +85°C. IC Role / Device Role / Timing Role: Industrial-grade LED driver with qualified temperature range and robust ESD protection (2 kV HBM). Use Value: Guarantees reliable LED operation under thermal cycling and electrostatic environments common in field service tools. |
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, higher current (25 mA per channel), but requires external oscillator; no internal prescaler/PWM registers. | Supports larger LED arrays; lacks LP3944ISQ/NOPB's single-chip dim rate programming - needs host to update PWM values continuously. | Choose when scaling beyond 8 LEDs or needing higher channel count; accept added firmware overhead for dynamic dimming. |
| PCA9635PW | 16-channel, I²C, built-in grayscale PWM (12-bit), but no internal oscillator - relies on external clock or master-provided timing. | Superior grayscale resolution (4096 steps vs. 256); however, requires continuous I²C updates for animation - increases bus load. | Prefer for high-fidelity color mixing where fine brightness control outweighs bus efficiency; not drop-in due to register map and timing architecture differences. |
Compared with TLC59116IPWR and PCA9635PW, LP3944ISQ/NOPB uniquely combines autonomous dimming (no host PWM updates), minimal I²C traffic (setup + trigger only), and compact 8-channel integration - making it optimal for cost-sensitive, low-power portable systems where animation complexity is moderate and bus bandwidth is constrained.
Availability
LP3944ISQ/NOPB is available at Aetrix Electronics and suitable for cellular phone indicator lighting, portable camera UIs, toy lighting effects, and industrial handheld device interfaces requiring stable component supply and long-term manufacturability.
Supply support for LP3944ISQ/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 leader specializing in analog, embedded processing, and connectivity technologies, with over 50 years of innovation in power management and interface solutions.
LP3944ISQ/NOPB belongs to TI's LED driver product line, designed specifically for low-pin-count, low-software-overhead LED control in battery-powered consumer and portable electronics.
FAQ
What is the maximum total current the LP3944ISQ/NOPB can sink across all channels?
The LP3944ISQ/NOPB supports up to 25 mA per LED output pin, with a hard limit of 200 mA total package sink current. This means no more than eight channels may operate at full 25 mA simultaneously. Exceeding 200 mA risks thermal shutdown or parametric drift. Designers must ensure sum of all active LED currents stays within this bound - for example, driving four LEDs at 40 mA each violates the specification and is not supported by the LP3944ISQ/NOPB.
Does the LP3944ISQ/NOPB require an external clock source to operate?
No, the LP3944ISQ/NOPB contains a fully integrated precision oscillator that provides all timing required for PWM dimming and internal logic. No external crystal, RC network, or clock input is needed - the oscillator operates across the full −40°C to +85°C temperature range with typical frequency variation under ±10%. This self-contained timing makes the LP3944ISQ/NOPB ideal for space-constrained designs where board area and component count must be minimized.
How does the LP3944ISQ/NOPB reduce I²C bus traffic compared to traditional LED drivers?
The LP3944ISQ/NOPB reduces I²C traffic by decoupling configuration from runtime control: after writing dimming parameters (PSC0/PWM0, PSC1/PWM1) and LED states (LS0/LS1) once, the host only sends single-byte commands to toggle individual LEDs ON/OFF or activate pre-programmed dim modes. Unlike shift-register-based drivers requiring 8+ bytes per frame update, the LP3944ISQ/NOPB needs just one byte per action - cutting bus utilization by >90% in animated lighting scenarios.
Can unused LED output pins on the LP3944ISQ/NOPB be repurposed as general-purpose I/O?
Yes, any LEDx pin not assigned to LED driving can be configured as a general-purpose open-drain I/O. When set to Hi-Z (B1/B0 = 00 in LS0/LS1 registers), the pin presents high impedance and may be used as an input with external pull-up; when driven LOW (B1/B0 = 01), it sinks current like an LED output - suitable for driving small loads or signaling. This GPIO expansion capability adds system flexibility without requiring additional ICs.
What is the function of the A0–A2 pins on the LP3944ISQ/NOPB?
The A0–A2 pins on the LP3944ISQ/NOPB set the three least-significant bits of its 7-bit I²C slave address, allowing up to eight LP3944ISQ/NOPB devices to share the same I²C bus. With base address 0x60, connecting A2–A0 to GND yields 0x60; tying A0 HIGH gives 0x61, and so on up to 0x67. These pins are sampled at power-up or reset - changes require hardware reconfiguration or reset assertion to take effect in the LP3944ISQ/NOPB.
LP3944ISQ/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)
LP3944ISQ/NOPB FAQ
1.How can I place an order for LP3944ISQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3944ISQ/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 LP3944ISQ/NOPB reliable?
The price and inventory of LP3944ISQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3944ISQ/NOPB is usually 5 days.
3.What payment methods are accepted for LP3944ISQ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3944ISQ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3944ISQ/NOPB?
LP3944ISQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3944ISQ/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 LP3944ISQ/NOPB?
For technical support, including LP3944ISQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3944ISQ/NOPB requirements.
6.How does Aetrix verify that LP3944ISQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LP3944ISQ/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 LP3944ISQ/NOPB meets industry standards.
7.What is the process for return or replacement of LP3944ISQ/NOPB?
All LP3944ISQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3944ISQ/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 LP3944ISQ/NOPB part is unused and in its original packaging.
Return procedure for LP3944ISQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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