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STMicroelectronics STLED325QTR
- Part No.:
- STLED325QTR
- Manufacturer:
- STMicroelectronics
- Category:
- Display Drivers
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
STLED325QTR.pdf
- Description:
- IC DRVR 8 SEGMENT 5 DIGIT 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,109
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Product details
Overview
STLED325QTR from STMicroelectronics is an I²C-interfaced LED controller/driver with integrated real-time clock (RTC), 8×2 keyscan, standby power management, and remote control decoding (RC5, NEC, RCA). It drives 5-digit × 8-segment common-anode LED displays with 16-step dimming, supports battery-backed RTC operation, and consumes <1 mA in standby mode. Used in front-panel interfaces of set-top boxes and home appliances.
For engineers reviewing the STLED325QTR datasheet, STLED325QTR pinout, STLED325QTR application, or STLED325QTR equivalent, key selection considerations include its integrated RTC accuracy (±2 ppm typical with calibration), programmable segment current via external RSET, wake-up sources (keys, IR, RTC alarm, AV/CEC pin), and QFN32 package thermal performance (θJA = 45 °C/W).
Technical Context
The STLED325QTR implements a dual-domain architecture: a display/control domain with 5-digit/8-segment drivers and 16-step PWM dimming, and a system-management domain integrating a 32.768 kHz crystal-based RTC with century-bit support, guard/watchdog timers, and switchover-capable VBAT/VCC power sense circuitry. All registers-including RTC time/date, alarm, keyscan RAM, and display RAM-are accessible via I²C.
Its remote control decoder supports protocol-specific state machines for RC5 (14-bit), NEC (32-bit), RCA (20-bit), and R-STEP, with IR_IN input conditioned by internal hysteresis and debounced before frame validation. Wake-up events trigger IRQ_N assertion and restore full functionality from sub-1 mA standby without host intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC supply | 5.0 V ±10% - powers core logic, display drivers, and RTC oscillator; enables direct interface with 5 V microcontrollers. |
| Segment current | Programmable up to 50 mA per segment via external RSET - allows red/green/blue LED brightness matching without external current sinks. |
| RTC accuracy | ±2 ppm typical with calibration register tuning - achieves <±1 minute/month drift, eliminating need for external temperature compensation. |
| Keyscan matrix | 8×2 (16-key) with auto-debounce and scan timing control - reduces host CPU polling load and eliminates external debounce hardware. |
| Standby current | <1 mA at VCC = 5 V - sustains RTC, keyscan monitoring, and wake-up detection while minimizing system standby power. |
| I²C interface | Standard/fast-mode (100/400 kHz), 7-bit address (0x54 default) - compatible with legacy and modern microcontroller I²C peripherals without level-shifting. |
| Thermal protection | 140 °C cutoff with 15 °C hysteresis - disables display drivers only; RTC and wake-up logic remain active during overtemperature events. |
Pinout & Package
STLED325QTR is housed in a thermally enhanced QFN32 (5 mm × 5 mm, 0.5 mm pitch) package with exposed thermal pad. Pin count and function mapping are validated per STMicroelectronics Doc ID 17576 Rev 1, Figure 3 and Table 9.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SCL / SDA | I²C serial bus interface | Enable bidirectional configuration and display data transfer using standard microcontroller I²C peripherals. |
| SEG1–SEG8 / KS1–KS8 | Segment outputs / Key-scan row drivers | Shared pins support multiplexed segment sinking and key-row sourcing; eliminate need for separate keyscan GPIOs. |
| DIG1–DIG5 | Digit anode drivers | Source current to common-anode LED digits; support 5-digit display with blanking control per digit. |
| XIN / XOUT | 32.768 kHz crystal oscillator terminals | Drive external tuning-fork crystal for RTC; internal load capacitors reduce BOM count. |
| IR_IN | Remote control signal input | Conditioned input accepts raw IR photodiode output; internal decoder handles protocol framing and checksum validation. |
| IRQ_N | Open-drain interrupt output | Asserts low on wake-up, keypress, RTC alarm, or error - enables event-driven host response without polling. |
| VBAT / WAKE_UP | Battery backup / multi-source wake input | VBAT maintains RTC during main power loss; WAKE_UP accepts edge-triggered signals from AV, CEC, or GPIO sources. |
| STBY / READY | Host-controlled standby enable / status indicator | STBY entry halts display refresh but preserves RAM; READY goes high when device exits reset or standby and is ready for commands. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated RTC with calibration | 32-bit counter, alarm, century bit, and 8-bit calibration register enabling ±2 ppm accuracy - removes need for external RTC IC and trim capacitor. |
| Multi-protocol IR decoder | Hardware-accelerated decoding for RC5, NEC, RCA, R-STEP, and Thomson R2000 - offloads CPU from bit-level IR processing and timing-critical frame validation. |
| Standby power management | Sub-1 mA retention mode with wake-on-key, wake-on-IR, wake-on-RTC-alarm, and wake-on-external-pin - enables zero-software-overhead low-power front panels. |
| Configurable LED drive | 16-step dimming + external RSET-controlled current (up to 50 mA/segment) - supports mixed-color LED displays with consistent perceived brightness. |
| Keyscan with auto-debounce | 8×2 matrix scanning at programmable rate (1–128 ms/frame) with 8-byte key RAM and interrupt-on-change - eliminates external debounce RC networks and firmware scan loops. |
Applications
| Set-Top Box Front Panel | DVD Player Display & Control |
|---|---|
|
Use Scenario: Driving 4-digit 7-segment display showing channel number, time, or playback status while detecting front-panel keypresses and IR remote commands. IC Role / Device Role / Timing Role: Central front-panel interface IC handling display refresh, keyscan, RTC-based timer functions, and IR decoding - replaces discrete shift registers, RTC, and microcontroller GPIO extensions. Use Value: Reduces MCU GPIO usage by 13+ pins, cuts BOM cost by consolidating 4+ functions, and enables <1 mA standby power for Energy Star compliance. |
Use Scenario: Managing alphanumeric LED display, volume/mute controls, and scheduled power-on via RTC alarm in DVD/VCR units. IC Role / Device Role / Timing Role: Standalone display and control peripheral with integrated RTC alarm wake-up - eliminates need for host CPU to maintain real-time scheduling during deep sleep. Use Value: Enables "wake at 7:00 AM to record" functionality without host CPU power, leveraging battery-backed RTC and IRQ_N-triggered boot sequence. |
| White Goods Control Panel | Home Appliance Timer Interface |
|
Use Scenario: Controlling oven/microwave LED display, keypad input, and cooking timer with power-loss resilience. IC Role / Device Role / Timing Role: Fault-tolerant front-end controller with VBAT-backed RTC and switchover circuitry - maintains time and alarm state during brownouts or main power disconnect. Use Value: Guarantees accurate cooking timer resume after power interruption; avoids EEPROM writes for time storage, improving reliability and endurance. |
Use Scenario: Providing user-adjustable countdown timers (e.g., laundry cycle, coffee maker) with visual feedback and audible alert triggering. IC Role / Device Role / Timing Role: Programmable RTC + interrupt generator - generates precise timebase for countdowns and asserts IRQ_N to trigger buzzer or display flash without CPU involvement. Use Value: Offloads timing-critical interrupt generation from host MCU, freeing CPU cycles for sensor processing or communication tasks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller/driver with RTC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6955ATL+ | 4-wire SPI interface; no integrated IR decoder; RTC lacks century bit and calibration register. | Requires external IR decoder IC and higher-accuracy crystal for comparable RTC stability. | Preferred where SPI is standard and IR functionality is handled elsewhere; lower integration but higher max segment current (100 mA). |
| PCA9622DP | I²C interface; 16-channel constant-current LED driver; no RTC, no keyscan, no IR decoder. | Needs separate RTC, keyscan, and IR ICs - increases board area and BOM count. | Chosen when only LED driving is required and system already includes dedicated RTC/keyscan subsystems. |
Compared with MAX6955ATL+ and PCA9622DP, STLED325QTR delivers highest functional integration for cost-sensitive consumer front panels-combining display, keys, RTC, and IR in one QFN32 package-while maintaining <1 mA standby and ±2 ppm RTC accuracy without external components.
Availability
STLED325QTR is available at Aetrix Electronics and suitable for set-top box manufacturing, white goods control panel assembly, and home appliance timer module production requiring stable component supply across extended product lifecycles.
Supply support for STLED325QTR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensor solutions for automotive, industrial, and consumer markets.
The STLED325 belongs to ST's LED controller and system-peripheral IC product line, engineered specifically to consolidate front-panel display, input, and timing functions in cost-sensitive consumer electronics with stringent standby power requirements.
FAQ
What is the maximum LED segment current supported by STLED325QTR?
The STLED325QTR supports up to 50 mA per segment, set precisely by an external RSET resistor connected to the ISET pin. This value is confirmed in Section 4.2.1 (DC electrical characteristics) of the official datasheet (Doc ID 17576 Rev 1), where ISEG = 12.5 × (1.25 V / RSET). The thermal protection circuit disables outputs above 140 °C to prevent damage.
Does STLED325QTR retain RTC time during main power loss?
Yes. When VCC drops below UVLO threshold, the STLED325QTR automatically switches to VBAT (supplied by coin cell or supercapacitor) to maintain RTC operation and register contents. This behavior is documented in Section 3.17.1 (Switchover) and Table 21 (Battery range and battery detect), supporting continuous timekeeping for >1 year on CR2032.
How many wake-up sources does STLED325QTR support?
The STLED325QTR supports five independent wake-up sources: front-panel keypress (via keyscan), infrared remote command (RC5/NEC/RCA), RTC alarm match, external signal on WAKE_UP pin, and AV/CEC pin assertion. Each source triggers IRQ_N and restores full functionality from standby, as detailed in Section 3.10.3 (Wake-up) and Figure 7.
Can STLED325QTR drive common-cathode LED displays?
No. The STLED325QTR is designed exclusively for common-anode LED configurations: DIGx pins source current to digit anodes, while SEGx/KSx pins sink current from segment cathodes. Driving common-cathode displays would require external level-shifting or inversion circuitry not supported by the internal architecture, per Section 3.4 (Display types) and Figure 4.
STLED325QTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 32-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Display Type:
- LED
- Configuration:
- 8 Segment
- Interface:
- I2C
- Digits or Characters:
- 5 Digits
- Current - Supply:
- 2 mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
STLED325QTR FAQ
1.How can I place an order for STLED325QTR through Aetrix?
Please submit a Request for Quotation (RFQ) for STLED325QTR 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 STLED325QTR reliable?
The price and inventory of STLED325QTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STLED325QTR is usually 5 days.
3.What payment methods are accepted for STLED325QTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STLED325QTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STLED325QTR?
STLED325QTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STLED325QTR 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 STLED325QTR?
For technical support, including STLED325QTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STLED325QTR requirements.
6.How does Aetrix verify that STLED325QTR is sourced from the original manufacturer or authorized distributors?
All STLED325QTR 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 STLED325QTR meets industry standards.
7.What is the process for return or replacement of STLED325QTR?
All STLED325QTR units undergo pre-shipment inspection (PSI). If there is an issue with STLED325QTR, 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 STLED325QTR part is unused and in its original packaging.
Return procedure for STLED325QTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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