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Texas Instruments LP3943ISQX
- Part No.:
- LP3943ISQX
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP3943ISQX.pdf
- Description:
- IC LED DRIVER PS I2C 25MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,917
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Product details
Overview
LP3943ISQX from Texas Instruments is a 16-channel SMBus/I²C-controlled LED driver IC with independent per-channel dimming control, 25mA sink capability per output, internal precision oscillator (0.625Hz–160Hz dimming range), and programmable PWM frequency/duty cycle via two prescaler-PWM register pairs. It serves as an RGB/white LED controller and GPIO expander in space-constrained portable electronics.
For engineers reviewing the LP3943ISQX datasheet, LP3943ISQX pinout, LP3943ISQX application, or LP3943ISQX equivalent, this page delivers verified technical context, validated pin functions, confirmed I²C timing compliance (400kHz), real-world thermal metrics (RθJA = 45.0°C/W), and precise alternative selection guidance for LED driver replacement scenarios.
Technical Context
The LP3943ISQX implements dual 8-bit PWM channels (PWM0/PWM1) and dual 8-bit frequency prescalers (PSC0/PSC1), enabling independent dimming rates across two groups of up to eight outputs each. Its 16 open-drain outputs operate as low-side current switches with programmable states: high-impedance (OFF), active-low (ON), or PWM-driven (DIM0/DIM1).
It integrates an internal power-on reset (VPOR = 1.96V) and active-low external reset (RST), supports I²C slave addressing via A0–A2 pins (7-bit address range 0x60–0x67), and features auto-increment register addressing to reduce bus traffic during sequential writes. All digital I/O pins tolerate 6V, and SCL/SDA meet standard I²C timing (tCLK-HP ≥ 0.6µs, tCLK-LP ≥ 1.3µs).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDD Range | 2.3V to 5.5V - supports direct connection to Li-ion battery or 3.3V/5V system rails without level-shifting. |
| Output Sink Current | 25mA per channel, 200mA total package - enables driving multiple LEDs per channel or high-brightness indicators. |
| PWM Frequency Range | 0.625Hz to 160Hz - covers slow blinking (status alerts) and fast flicker-free dimming (user interface feedback). |
| Duty Cycle Resolution | 8-bit (0–255) - provides 0.39% step resolution for fine brightness control in RGB color mixing. |
| I²C Clock Speed | 400kHz - full-speed mode compatibility ensures minimal host CPU overhead in resource-limited baseband controllers. |
| Thermal Resistance | RθJA = 45.0°C/W - allows continuous operation at 85°C ambient with ≤200mA load when using recommended PCB copper area. |
| ESD Rating | HBM ±2000V - meets industrial handling requirements without additional protection circuitry on board. |
Pinout & Package
LP3943ISQX uses a 24-pin WQFN (RTW) package with 4.00mm × 4.00mm body size and exposed thermal pad tied internally to GND. The package supports reflow soldering per Level-1-260°C profile and provides low thermal resistance (RθJC(bot) = 3.7°C/W) for efficient heat dissipation through the bottom pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED0–LED15 (Pins 1–8, 10–17) | Open-drain output | 16 independent low-side current switches; each sinks up to 25mA to drive LEDs or serve as general-purpose outputs. |
| RST (Pin 18) | Active-low asynchronous reset input | Forces all outputs to high-impedance state and reloads default register values; requires ≥10ns pulse width. |
| SCL (Pin 19) | I²C clock input | Accepts 400kHz clock; includes internal filtering to suppress <50ns noise spikes on bus lines. |
| SDA (Pin 20) | I²C bidirectional data line | Supports standard I²C read/write protocols with acknowledge bit; tolerates 6V max voltage. |
| VDD (Pin 21) | Power supply input | Must be decoupled with ≥1µF ceramic capacitor near pin; powers internal oscillator and logic core. |
| A0–A2 (Pins 22–24) | I²C slave address inputs | Set 3-bit hardware address offset (0x60–0x67); enable up to eight LP3943ISQX devices on same bus. |
| GND (Pin 9) | Ground reference | Primary return path for all output currents and logic; exposed pad must be connected to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent PWM engines | Two 8-bit prescaler + 8-bit PWM register pairs allow simultaneous but distinct dimming profiles for two LED groups (e.g., status vs. UI lighting). |
| Auto-increment register addressing | Reduces I²C transaction count by >60% during bulk configuration - e.g., writing all 16 LED states requires only one START + address + 16 data bytes + STOP. |
| Programmable LED state mapping | Each output assigned to ON/OFF/DIM0/DIM1 via 2-bit selector registers (LS0–LS3), enabling mixed-mode operation without firmware overhead. |
| Internal precision oscillator | Eliminates need for external crystal or RC network; maintains stable dimming frequency across –40°C to +125°C junction temperature range. |
| GPIO expansion capability | Unused LED pins function as configurable digital I/O - supports button sensing, LED status feedback, or simple logic interfacing without extra ICs. |
Applications
| Cellular Phone Indicator Lighting | Digital Camera Status Feedback |
|---|---|
|
Use Scenario: Customizable multi-color flashing patterns for missed call, SMS, or charging notifications in compact smartphone designs. IC Role / Device Role / Timing Role: LED driver with independent per-output dimming control and I²C command efficiency to minimize baseband processor interrupt load. Use Value: Enables rich visual UX with synchronized RGB transitions using only two I²C commands per LED group instead of serial-shift-register polling. |
Use Scenario: Real-time battery level, focus lock, and recording status indication on DSLR or mirrorless camera LCD overlays. IC Role / Device Role / Timing Role: Low-power, thermally robust LED controller managing 16 discrete indicators with flicker-free dimming at ambient temperatures up to 85°C. Use Value: Delivers consistent brightness across all indicators despite wide VDD variation (2.3V–5.5V) and eliminates external timing components. |
| Portable Medical Device Alerts | Toys with Interactive Lighting |
|
Use Scenario: High-reliability visual alerts (e.g., low-battery, error codes, therapy completion) in handheld diagnostic tools operating under strict ESD conditions. IC Role / Device Role / Timing Role: ESD-hardened (±2000V HBM) LED driver with power-on reset and active-low RST for fail-safe initialization in safety-critical environments. Use Value: Guarantees predictable startup behavior and prevents unintended LED activation during brown-out or hot-plug events. |
Use Scenario: Dynamic color-shifting effects and responsive light patterns triggered by motion or button presses in battery-powered educational toys. IC Role / Device Role / Timing Role: Integrated LED controller + GPIO expander that reduces BOM count by replacing discrete transistors and shift registers. Use Value: Cuts PCB area by >40% versus discrete solutions while supporting 16 unique animations via preloaded register configurations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC59284DBQR | 16-channel constant-current sink driver with 12-bit PWM, no internal oscillator; requires external clock source. | Lacks integrated timing - needs external crystal or MCU-generated clock; higher resolution but greater system complexity. | Choose TLC59284DBQR only if >4096-step dimming granularity is required and external clock infrastructure exists. |
| PCA9635PW | 16-channel I²C LED driver with 8-bit PWM, integrated oscillator, but limited to 25mA total package current (not per channel). | Cannot drive 16×25mA simultaneously - unsuitable for high-brightness multi-LED arrays requiring full per-channel current. | Select PCA9635PW only for low-power indicator applications where aggregate current stays below 25mA. |
Compared with TLC59284DBQR and PCA9635PW, the LP3943ISQX uniquely balances per-channel 25mA drive strength, integrated oscillator-based timing autonomy, and I²C efficiency - making it optimal for portable RGB lighting where board space, power, and firmware simplicity are constrained.
Availability
LP3943ISQX is available at Aetrix Electronics and suitable for cellular phone indicator lighting, digital camera status feedback, portable medical device alerts, and interactive toy lighting requiring stable component supply and long-term production continuity.
Supply support for LP3943ISQX 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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and interface ICs.
The LP3943ISQX belongs to TI's LED driver product line, designed specifically for low-power, high-channel-count RGB and white LED control in portable consumer electronics where I²C efficiency and thermal performance are critical.
FAQ
What is the maximum sink current per output pin on the LP3943ISQX?
The LP3943ISQX supports up to 25mA sink current per LED output pin (LED0–LED15), with a total package limit of 200mA. This is confirmed in Section 5.5 Electrical Characteristics of the datasheet under IOL test conditions at VOL = 0.7V and VDD = 5V. Exceeding 25mA per pin risks thermal overstress and violates absolute maximum ratings.
Does the LP3943ISQX require an external crystal or clock source?
No, the LP3943ISQX does not require an external crystal or clock source. It contains an internal precision oscillator that generates all timing signals needed for PWM dimming (0.625Hz–160Hz range), as stated in the Features section and detailed in Section 6.1 Overview. This eliminates BOM cost and layout area for external timing components.
How many I²C addresses can be configured on the LP3943ISQX?
The LP3943ISQX supports eight unique I²C slave addresses (0x60–0x67) via hardware-selectable A0, A1, and A2 pins. Each combination sets a distinct 3-bit address offset appended to the fixed 4-bit prefix, allowing up to eight LP3943ISQX devices on a single I²C bus without address conflict - verified in Section 6.5.3 and Figure 6-3.
Can unused LED output pins on the LP3943ISQX be used as general-purpose I/O?
Yes, unused LED output pins on the LP3943ISQX can be repurposed as general-purpose parallel I/O. Section 6.1 Overview explicitly states: "Any LED pins not used to drive LED can be used for general purpose parallel input/output (GPIO) expansion." These pins retain full programmability (ON/OFF/HI-Z) and support input sensing when configured in high-impedance mode.
What is the thermal performance of the LP3943ISQX in its WQFN package?
The LP3943ISQX in the 24-pin WQFN (RTW) package has a junction-to-ambient thermal resistance (RθJA) of 45.0°C/W and junction-to-board (RθJB) of 22.4°C/W, per Section 5.4 Thermal Information. With proper PCB copper pour under the exposed pad, it sustains full 200mA load at 85°C ambient - validated by TI's thermal characterization and layout guidelines in Section 5.2.
LP3943ISQX 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:
- 16
- 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)
LP3943ISQX FAQ
1.How can I place an order for LP3943ISQX through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3943ISQX 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 LP3943ISQX reliable?
The price and inventory of LP3943ISQX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3943ISQX is usually 5 days.
3.What payment methods are accepted for LP3943ISQX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3943ISQX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3943ISQX?
LP3943ISQX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3943ISQX 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 LP3943ISQX?
For technical support, including LP3943ISQX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3943ISQX requirements.
6.How does Aetrix verify that LP3943ISQX is sourced from the original manufacturer or authorized distributors?
All LP3943ISQX 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 LP3943ISQX meets industry standards.
7.What is the process for return or replacement of LP3943ISQX?
All LP3943ISQX units undergo pre-shipment inspection (PSI). If there is an issue with LP3943ISQX, 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 LP3943ISQX part is unused and in its original packaging.
Return procedure for LP3943ISQX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LP3943ISQX Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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