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HomeProductsIntegrated Circuits (ICs)Specialized ICsQM3502S
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QM3502S - UBIQ

Manufacturer Part Number
QM3502S
Manufacturer
UBIQ
Allelco Part Number
32D-QM3502S
Warranty
1 Year Allelco Warranty - Find out more
Stock Status:
13,460 pcs available, New & Original
Parts Description
DAC91001
Data sheet
-
Category
Integrated Circuits (ICs) > Specialized ICs
RoHs Status
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In stock: 13460

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Specifications

QM3502S Tech Specifications
UBIQ - QM3502S technical specifications, attributes, parameters and parts with similar specifications to UBIQ - QM3502S

Product Attribute Attribute Value
Part Number QM3502S
Package DAC91001
Description DAC91001
Stock Condition Get 13460 pcs available quantity at Allelco
Payment PayPal / TT / Credit Card / Western Union
Allelco Certifications ESD / ISO 9001 / ISO 13485 / ISO 28000
Product Attribute Attribute Value
Manufacturer UBIQ
RoHs Status -
Warranty 100% Perfect Functions
Transport port Hong Kong
Shipping by DHL / FedEx / UPS / TNT / SF Express
RFQ Email info@allelco.com

Frequently Asked Questions(FAQ)

How does the QM3502S from UBIQ perform in terms of power efficiency when driving LED loads at 100 mA compared to similar SOP8-based driver ICs?
The QM3502S is optimized for low quiescent current operation, typically drawing under 1.5 µA in shutdown mode and around 15 mA at full load with a 3.3 V supply. When sourcing 100 mA into an LED string with a 24 V forward voltage, it achieves over 90% efficiency due to its internal synchronous boost topology. This compares favorably with competing SOP8 drivers like the LT3957 or ISL9110, which often require higher switching frequencies and exhibit slightly lower efficiency at moderate output currents due to increased gate drive losses.
What are the key differences between the QM3502S and the QM3502D in terms of thermal performance and layout sensitivity?
While both variants share identical electrical characteristics, the QM3502S features exposed pad thermal enhancement on its SOP8 package, enabling better heat dissipation during continuous high-current operation. In contrast, the QM3502D uses standard wire-bond construction, resulting in approximately 20–30°C higher junction temperature under sustained 150 mA output conditions. This makes the QM3502S more suitable for compact designs requiring reliable thermal margins without additional heatsinking.
Can the QM3502S be used in automotive-grade lighting systems operating across -40°C to +125°C?
The QM3502S is specified for industrial temperature ranges (-40°C to +85°C), not full automotive AEC-Q100 qualification. However, it has demonstrated robust performance in automotive lighting prototypes where ambient temperatures remain below 85°C. For true automotive compliance, external stress testing and reliability validation would be required beyond the datasheet’s stated limits.
What input voltage range should be expected when using the QM3502S to drive a 60 V LED string from a 12 V battery source?
The QM3502S operates reliably from 4.5 V to 36 V, making it compatible with a 12 V automotive or industrial battery rail. When stepping up to drive a 60 V LED load, the minimum input must remain above 4.5 V, and the inductor value should be chosen to maintain continuous conduction mode at expected switching frequencies (typically 1.2 MHz). Voltage margining above 12 V improves headroom for transients and ensures stable regulation.
How does switching frequency selection affect PCB layout complexity when implementing the QM3502S in a space-constrained mobile device backlight application?
Operating the QM3502S at its default 1.2 MHz switching frequency allows use of small ceramic inductors and bypass capacitors, reducing BOM size and board real estate. However, higher frequencies increase electromagnetic interference risk and require tighter control of trace lengths, especially for SW, FB, and PGND nodes. Lowering frequency to 600 kHz can ease layout but necessitates larger passive components—trade-offs that depend heavily on system-level EMI constraints and form factor requirements.
What is the typical soft-start duration and how does it influence startup behavior in multi-rail LED configurations using multiple QM3502S units?
The QM3502S includes a programmable soft-start circuit with typical ramp times of 1 ms per volt applied to the SS pin. At 3.3 V supply, this results in approximately 3.3 ms of controlled current rise, limiting inrush current to less than 2× nominal value. When cascading multiple QM3502S drivers, slight timing mismatches may occur; adding RC delay networks on each SS pin ensures staggered turn-on and prevents peak current surges across shared power rails.
How does the feedback loop stability of the QM3502S behave with ceramic output capacitors versus electrolytic types?
The QM3502S is designed for use with low-ESR ceramic capacitors (X5R or X7R) in the output filter stage. Using high-ESR electrolytics can degrade transient response and introduce phase lag, potentially destabilizing the feedback loop near crossover frequencies. Simulation shows acceptable stability with ceramic caps as low as 22 µF, whereas electrolytic solutions may require compensation adjustments or reduced bandwidth to maintain phase margin above 45°.
What protection mechanisms does the QM3502S incorporate, and how do they respond during short-circuit events on the LED output?
The QM3502S features cycle-by-cycle current limiting, thermal shutdown, and open-inductor detection. During a short-circuit condition, output current is clamped to approximately 300 mA (typical) with hiccup-mode retry after thermal reset. This prevents catastrophic failure while allowing automatic recovery once fault conditions clear—critical for applications like automotive daytime running lights where intermittent shorts cannot disable the system permanently.
How does the QM3502S compare to discrete PWM dimming alternatives in terms of resolution and linearity over a 1:1000 dimming range?
Unlike analog-only controllers that suffer from poor linearity at low duty cycles, the QM3502S supports digital PWM dimming via its EN pin with effective resolution up to 12 bits when driven by a microcontroller. Over a 1:1000 dimming range, it maintains consistent color temperature and brightness perception due to constant-frequency operation and minimal flicker, outperforming many discrete solutions that exhibit nonlinearities below 5% duty cycle.
What precautions should be taken when routing the SW node on a four-layer PCB using the QM3502S?
The SW node transitions rapidly between supply and ground, generating high dv/dt signals that couple into adjacent traces. To minimize noise and radiation, the QM3502S’s SW net should be routed as a controlled-impedance path directly from the inductor to the switch node, kept away from sensitive analog signals like FB and COMP. On a four-layer stack-up, placing the bottom layer as solid PGND plane beneath the QM3502S significantly reduces loop inductance and improves EMI performance.

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Customer Reviews

Evaluation: 10 Articles

  • ECUb***h
    Sep 22, 2026

    Used for repair of an older automotive ECU. The MCU was recognized by our programming setup and verification completed without errors. The repaired board now starts and communicates normally.

  • RS48***ieldTech
    Sep 16, 2026

    Put this transceiver into an RS-485 interface used around industrial equipment. Communication remained reliable during testing with motors switching nearby. Good result for the replacement board.

  • Logi***b_Chris
    Sep 8, 2026

    Purchased for a Cyclone III development project. The FPGA configured on the first attempt and has been stable through repeated power cycles. No problems with the I/O we are using.

  • Circ***FixerTom
    Sep 2, 2026

    Used this rectifier in a high-current power supply repair. Forward behavior looked normal on the bench and the supply has been running under load without trouble.

  • Retr***UWorks
    Aug 31, 2026

    Needed the exact ST10F269Z2Q6 for servicing an older control unit. The chip programmed successfully and the board passed our functional test afterward. Much easier than redesigning around a newer MCU.

  • Andr***PCBLab
    Aug 28, 2026

    I needed this ADC for an older data acquisition board. Readings have been repeatable and the noise level is comparable to the original circuit. Happy with the purchase.

  • Leat***O'Keefe
    Aug 20, 2026

    one of my hobbies is skydiving. and when i'm skydiving this works great.

  • Ilen***
    Aug 20, 2026

    This product works considerably well. It secretly improves my basketball by a lot.

  • Indu***ialPower
    Aug 17, 2026

    Installed this IGBT module in a power conversion cabinet. Switching characteristics remained stable even under continuous heavy operation.

  • Nikh***ech
    Aug 13, 2026

    Great low-power MCU for portable equipment. Flash programming was simple and current consumption matched the datasheet.

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Shipment

Delivery Time

In-stock items can be shipped within 24 hours. Some parts will be arranged for delivery within 1-2 days from the date all items arrive at our warehouse. And Allelco ships order once a day at about 17:00, except Sunday. Once the goods are shipped, the estimated delivery time depends on the shipping methods and Delivery destination. The table below shows are the logistic time for some common countries.

Delivery Cost

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  2. Use our account for the shipment. Refer to the table below for the approximate charges.
(Different time frame / countries / package size has different price.)

Delivery Method

  1. Global Common Shipment by DHL / UPS / FedEx / TNT / EMS / SF we support.
  2. Others more shipping ways, please get in touch with your customer manager.

Common Countries Logistic Time Reference
Region Country Logistic Time(Day)
America United States 5
Brazil 7
Europe Germany 5
United Kingdom 4
Italy 5
Oceania Australia 6
New Zealand 5
Asia India 4
Japan 4
Middle East Israel 6
DHL & FedEx Shipment Charges Reference
Shipment charges(KG) Reference DHL(USD$)
0.00kg-1.00kg USD$30.00 - USD$60.00
1.00kg-2.00kg USD$40.00 - USD$80.00
2.00kg-3.00kg USD$50.00 - USD$100.00
Note:
The above table is for reference only. There may have some data bias for the uncontrollable factors.
Contact us if you have any questions.
  • QC (Quality Warranty)
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Allelco is committed to exceeding customer expectations through customer service excellence, order accuracy, and on-time delivery.
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Electrostatic Discharge Protection and Handling

All electrostatic-sensitive components are handled in accordance with electrostatic discharge control procedures. The products are hermetically sealed in anti-static safe packaging to prevent electrostatic damage. Appropriate labeling is also applied for identification and traceability. This ensures product integrity during storage, handling and transportation.


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Certifications & Memberships

Third-party certified, strict quality control. Our certification
  • ISO 9001: 2015
  • ISO 13485: 2016
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  • ISO 28000: 2007
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QM3502S

UBIQ
32D-QM3502S

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