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Texas Instruments LP5521YQ/NOPB
- Part No.:
- LP5521YQ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-VFQFN Exposed Pad
- Datasheet:
-
LP5521YQ/NOPB.pdf
- Description:
- IC LED DRVR RGLTR I2C 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,603
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Product details
Overview
LP5521YQ/NOPB from Texas Instruments is a three-channel RGB LED driver IC with integrated adaptive charge pump, programmable constant-current outputs (0–25.5 mA per channel), 8-bit PWM control, and autonomous program execution memory. It operates across 2.7–5.5 V input, supports I²C interface, and delivers lighting effects for mobile indicator and backlight applications without continuous host MCU involvement.
For engineers reviewing the LP5521YQ/NOPB datasheet, LP5521YQ/NOPB pinout, LP5521YQ/NOPB application, or LP5521YQ/NOPB equivalent, key selection considerations include its 1×/1.5× auto-switching charge pump efficiency, 1% current matching across R/G/B channels, 50 mV typical saturation voltage, dual 32-kHz clock synchronization capability, and WQFN-24 package compatibility with space-constrained handheld designs.
Technical Context
The LP5521YQ/NOPB integrates a pre-regulated switched-capacitor charge pump with automatic gain selection (1× or 1.5×) based on real-time LED forward voltage monitoring and headroom detection. Its three independent current sources each feature 8-bit digital current setting (100 µA resolution) and dual-mode PWM (256 Hz or 558 Hz), enabling precise color mixing and dynamic lighting sequences.
Autonomous operation is enabled via on-chip SRAM program memory executing compiled command sets; trigger I/O and CLK_32K allow inter-device synchronization, while INT and GPO provide host notification and peripheral control. The device enters power-save mode automatically when outputs are inactive, reducing supply current to 10 µA with external 32-kHz clock.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 5.5 V - Supports full Li-ion battery range without external regulation. |
| LED Output Current | 0–25.5 mA per channel (R/G/B) - Programmable in 100 µA steps for precise brightness control. |
| Current Matching | ±1% max deviation - Ensures consistent RGB color balance under varying thermal/load conditions. |
| Charge Pump Output | 4.55 V typical (1.5× mode, no load) - Regulated output enables driving high-VF LEDs from low battery voltages. |
| Saturation Voltage | 50 mV typical at 17.5 mA - Minimizes power loss and heat generation in current-source stage. |
| I²C Interface Speed | Up to 400 kHz - Compatible with standard/fast-mode I²C hosts for efficient register configuration. |
| Standby Current | 0.2 µA (EN = 0) - Enables ultra-low-power system sleep states without disconnecting supply. |
Pinout & Package
LP5521YQ/NOPB uses a 5.00 mm × 4.00 mm WQFN-24 package with exposed thermal pad (NJA suffix). Pin functions are validated per TI SNVS441I Rev. I datasheet, Section 5.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 | CFLY2P, CFLY1P | Positive terminals of flying capacitors - Connect to 0.47 µF X5R/X7R ceramic caps for charge pump energy transfer. |
| 3 | VDD | Main power supply input - Decoupled with 1 µF ceramic capacitor near pin for stable operation. |
| 4, 24 | GND | Analog/digital ground reference - Requires low-impedance PCB connection to thermal pad for thermal performance. |
| 5 | CLK_32K | 32-kHz clock input - Accepts internal oscillator or external crystal for synchronized multi-device timing. |
| 6 | INT | Open-drain interrupt output - Signals end-of-program or fault condition; pulled up externally to VDD. |
| 7 | TRIG | Bi-directional trigger I/O - Used for inter-device synchronization or as general-purpose digital input/output. |
| 13, 15 | SDA, SCL | I²C data/clock lines - Support 400 kHz operation; require pull-up resistors to VDD (typically 2.2–10 kΩ). |
| 14 | EN | Active-high chip enable - Powers up device and releases reset; must be held high ≥1 ms before I²C access. |
| 16 | GPO | Push-pull general-purpose output - Drives logic-level signals (0.3 V low, VDD–0.5 V high) for peripheral control. |
| 17–19 | R, G, B | Constant-current LED outputs - Each sinks up to 25.5 mA; connected internally to charge pump or VDD (R only). |
| 20, 21 | ADDR_SEL0, ADDR_SEL1 | I²C address select inputs - Set one of four possible slave addresses (0x30–0x33) for multi-device bus sharing. |
| 22 | VOUT | Charge pump regulated output - Supplies boosted voltage to G/B drivers and optionally R driver (configurable). |
| 23, 24 | CFLY2N, CFLY1N | Negative terminals of flying capacitors - Return path for charge pump switching phases; connect directly to GND. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive 1×/1.5× charge pump | Automatically selects gain mode based on real-time LED forward voltage monitoring to maintain >95% drive efficiency across battery discharge cycle. |
| Autonomous lighting engine | On-chip SRAM stores compiled lighting programs; executes sequences independently after initialization-reducing host MCU overhead and power consumption. |
| Three-channel current matching | ≤1% mismatch between R/G/B outputs at 17.5 mA ensures accurate RGB color reproduction without calibration. |
| Dual PWM frequency modes | 256 Hz (32-kHz clock sourced) or 558 Hz (internal oscillator) - Enables flicker-free operation and flexible timing for visual effects. |
| Configurable R-channel power path | R output can be routed to VDD instead of VOUT, bypassing charge pump for low-VF red LEDs-improving system efficiency by eliminating unnecessary voltage boost. |
| Integrated protection | Soft-start, overcurrent detection, short-circuit protection, and thermal shutdown (TJ = 150°C) ensure robust operation in portable environments. |
Applications
| RGB Keypad Backlighting | Mobile Indicator Lights |
|---|---|
|
Use Scenario: Illuminating alphanumeric keys on smartphones or feature phones with user-selectable colors and animated patterns. IC Role / Device Role / Timing Role: LP5521YQ/NOPB acts as autonomous RGB current source, generating synchronized PWM waveforms and executing stored lighting sequences without CPU polling. Use Value: Reduces host processor load and extends battery life while enabling rich cosmetic lighting effects using only four 0.47–1 µF ceramic capacitors. |
Use Scenario: Providing status indication (charging, notification, Bluetooth pairing) on compact wearable devices and handheld POS terminals. IC Role / Device Role / Timing Role: LP5521YQ/NOPB serves as self-contained LED controller, using its internal oscillator or 32-kHz sync input to coordinate blink timing across multiple units. Use Value: Eliminates need for external timing components and firmware-driven GPIO toggling-enabling reliable, low-power visual feedback in size-constrained designs. |
| LCD Sub-Display Backlight | Blood Glucose Meter UI |
|
Use Scenario: Driving small-area white or RGB backlight for secondary displays in medical or industrial handheld instruments. IC Role / Device Role / Timing Role: LP5521YQ/NOPB functions as precision current regulator with programmable dimming curves, supporting smooth brightness transitions via 8-bit PWM resolution. Use Value: Achieves uniform illumination and color consistency across display area with <50 mV saturation voltage-minimizing thermal rise and improving contrast ratio. |
Use Scenario: Delivering intuitive, color-coded result indicators (e.g., green OK, red error, yellow warning) in FDA-cleared diagnostic devices. IC Role / Device Role / Timing Role: LP5521YQ/NOPB operates as safety-relevant visual annunciator, leveraging autonomous program memory to guarantee deterministic light behavior independent of main application firmware. Use Value: Provides fail-safe visual signaling with verified current accuracy (±4% over temperature) and built-in short-circuit protection-supporting IEC 62304 compliance requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar RGB LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LP55231YFFR | Four-channel architecture; adds dedicated white LED channel and enhanced program memory; requires identical 0.47 µF fly caps but uses DSBGA-20 package. | Supports RGBW configurations and longer lighting sequences; lacks TRIG pin for inter-device sync. | Select when expanding to quad-channel lighting or requiring higher program memory depth; verify PCB layout change for smaller DSBGA footprint. |
| TPS61165DRVR | Single-output boost converter LED driver; no integrated program memory, PWM generator, or I²C interface-requires external MCU control. | Targeted at high-brightness monochrome backlighting; not suitable for autonomous RGB effects or color mixing. | Choose only for cost-sensitive, single-color applications where host MCU handles all timing and sequencing logic. |
Compared with LP5521YQ/NOPB, LP55231YFFR offers expanded channel count and memory but sacrifices trigger-based synchronization and increases integration complexity, while TPS61165DRVR provides higher output current capability but eliminates autonomous operation and RGB control entirely-making LP5521YQ/NOPB optimal for compact, intelligent multi-color lighting subsystems.
Availability
LP5521YQ/NOPB is available at Aetrix Electronics and suitable for RGB keypad backlighting, mobile indicator lights, LCD sub-display backlighting, blood glucose meter UIs, and handheld POS terminals requiring stable component supply across production lifecycles.
Supply support for LP5521YQ/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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and interface solutions for industrial, automotive, and consumer markets.
The LP5521YQ/NOPB belongs to TI's LP55xx family of autonomous LED drivers, designed specifically for low-power, space-constrained mobile and portable electronics requiring rich visual feedback without continuous host intervention.
FAQ
What is the maximum LED current supported by the LP5521YQ/NOPB?
The LP5521YQ/NOPB supports up to 25.5 mA per channel (R, G, B) with 100 µA resolution via 8-bit current registers. This limit applies across the full operating temperature range (–30°C to +85°C) and input voltage range (2.7 V to 5.5 V), as confirmed in Section 6.7 of the SNVS441I datasheet. Exceeding this value risks saturation and reduced efficiency.
Does the LP5521YQ/NOPB require external inductors or resistors for basic operation?
No, the LP5521YQ/NOPB requires only four external ceramic capacitors: two 0.47 µF flying capacitors (CFLY1, CFLY2) and two 1 µF input/output capacitors (CIN, COUT). It contains an integrated adaptive charge pump and programmable current sources-eliminating inductors, sense resistors, and external timing components required by discrete LED driver solutions.
How does the LP5521YQ/NOPB achieve autonomous operation without a host processor?
The LP5521YQ/NOPB achieves autonomy through on-chip SRAM program memory that stores compiled lighting sequences. Once loaded via I²C, the internal MCU executes commands-including PWM timing, current ramping, and channel enable/disable-without further host interaction. This capability is documented in Sections 7.5 and 8.2 of the LP5521 datasheet.
Can the R channel of the LP5521YQ/NOPB be powered directly from VDD instead of the charge pump?
Yes, the R channel of the LP5521YQ/NOPB can be configured to connect directly to VDD using the R_TO_BATT bit (bit 5) in register 08H. This bypasses the charge pump for red LEDs with low forward voltage, improving efficiency. G and B channels remain tied to VOUT and cannot be re-routed-this functionality is explicitly defined in Section 7.3.2 of the datasheet.
What thermal performance can be expected from the LP5521YQ/NOPB in a typical 4-layer PCB layout?
In a standard 4-layer PCB with 1-in² 2-oz copper thermal pad connected to internal ground planes, the LP5521YQ/NOPB (WQFN-24) exhibits a junction-to-ambient thermal resistance (RθJA) of 38.4°C/W, per Section 6.4 of SNVS441I. At 75 mA total LED current and 3.6 V input, typical power dissipation remains below 120 mW-keeping junction temperature well within the 125°C limit even at +85°C ambient.
LP5521YQ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Switched Capacitor (Charge Pump)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 3
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 4.55V
- Current - Output / Channel:
- 25.5mA
- Frequency:
- 1.25MHz
- Dimming:
- I2C
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (5x4)
LP5521YQ/NOPB FAQ
1.How can I place an order for LP5521YQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP5521YQ/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 LP5521YQ/NOPB reliable?
The price and inventory of LP5521YQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP5521YQ/NOPB is usually 5 days.
3.What payment methods are accepted for LP5521YQ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP5521YQ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP5521YQ/NOPB?
LP5521YQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP5521YQ/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 LP5521YQ/NOPB?
For technical support, including LP5521YQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP5521YQ/NOPB requirements.
6.How does Aetrix verify that LP5521YQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LP5521YQ/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 LP5521YQ/NOPB meets industry standards.
7.What is the process for return or replacement of LP5521YQ/NOPB?
All LP5521YQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP5521YQ/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 LP5521YQ/NOPB part is unused and in its original packaging.
Return procedure for LP5521YQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LP5521YQ/NOPB Tags
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