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Microchip Technology MIC3291-25YML-TR
- Part No.:
- MIC3291-25YML-TR
- Manufacturer:
- Microchip Technology
- Category:
- LED Drivers
- Package:
- 8-VFDFN Exposed Pad, 8-MLF®
- Datasheet:
-
MIC3291-25YML-TR.pdf
- Description:
- IC LED DRIVER RGLTR 1.2A 8MLF
- Quantity:
- Payment:
- Shipping:
Inventory:2,226
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Product details
Overview
MIC3291-25YML-TR from Micrel is a 1.2MHz PWM boost LED driver IC optimized for constant-current white LED backlighting, featuring internal Schottky diode, single-wire 16-step linear brightness control, and 25V over-voltage protection for up to six-series WLED strings. It operates from 2.5V–6.5V input (e.g., single-cell Li-Ion), delivers >500mA switch current, and maintains ±5% LED current accuracy via 250mV feedback reference.
For engineers reviewing the MIC3291-25YML-TR datasheet, MIC3291-25YML-TR pinout, MIC3291-25YML-TR application, or MIC3291-25YML-TR equivalent, this page provides verified package mapping (2mm × 2mm MLF®-8L), validated pin functions, confirmed OVP threshold (22.1–25V), startup timing (140µs), and real-world digital interface timing constraints (tMODE_UP: 100–160µs, tshutdown: 1260µs).
Technical Context
The MIC3291-25YML-TR implements constant-frequency current-mode PWM control at 1.2MHz with slope compensation, integrating a bipolar output transistor, gm error amplifier, and digital interface with D/A converter. Its feedback loop references a precise 250mV threshold to set LED current via external sense resistor (ILED = 250mV / RFB).
Digital control uses true single-wire serial programming: logic-level pulses on the DC pin configure brightness (0–15), mode (count-up/count-down), or shutdown-without requiring continuous MCU PWM generation. Startup defaults to brightness level 15 in count-down mode, with presettable initial level during tPROG_SETUP (35–50µs after DC high).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.2MHz fixed PWM - enables compact 10µH inductor and 0.27µF output capacitor, reducing board area and input ripple. |
| Feedback Reference Voltage | 250mV ±5% - sets LED current with high accuracy using small-value sense resistor (e.g., 12.4Ω → 20.2mA), minimizing power loss. |
| OVP Threshold | 22.1V to 25V - protects against open-circuit LED string failure when driving up to six-series WLEDs (≈21V typical forward voltage). |
| Input Voltage Range | 2.5V to 6.5V - supports direct operation from single-cell Li-Ion (3.0–4.2V) or 3–4 cell alkaline/NiMH without pre-regulation. |
| Shutdown Current | <1µA - preserves battery life in portable devices during display-off states. |
| Switch Current Limit | 500mA to 1200mA - ensures robust start-up into full LED load while limiting peak stress on internal bipolar transistor. |
| Junction Temperature Range | −40°C to +125°C - qualified for automotive cabin and industrial handheld environments with no derating up to 85°C ambient. |
Pinout & Package
Package: 2mm × 2mm, 8-pin leadless MLF® (Micrel MLF-8L), RoHS-compliant, NiPdAu lead finish, exposed thermal pad (GND-connected).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Output and OVP node | Connects to anode of LED string; internal OVP circuit monitors this pin and disables switching if voltage exceeds 25V. |
| 2 (VIN) | Power supply input | Accepts 2.5V–6.5V; powers internal circuitry and supplies gate drive for bipolar switch; bypass with 1µF ceramic capacitor. |
| 3 (DC) | Digital control interface | Single-wire input for brightness programming (pulse edges), mode change (tMODE_UP/tMODE_DOWN), and shutdown (≥1260µs low pulse). |
| 4 (GND) | Ground return | Primary ground connection; ties to backside thermal pad for thermal management and noise reduction. |
| 5 (NC) | No connect | Not bonded internally; must be left floating or tied to GND per layout best practice-no electrical function. |
| 6 (FB) | Current sense feedback | Connects to LED cathode via external sense resistor; 250mV reference sets LED current (ILED = 250mV / RFB). |
| 7 (SW) | Switch node | Internal bipolar collector output; connects to inductor; high dv/dt node requiring tight layout and Kelvin routing for stability. |
| 8 (GND) | Ground return | Secondary ground connection; ties to same net as Pin 4 and thermal pad to minimize ground bounce in high-frequency switching. |
Key Features
| Feature | Design Value |
|---|---|
| Single-wire digital interface | Eliminates need for dedicated PWM generator or I²C/SPI bus-brightness, mode, and shutdown controlled via timed logic pulses on one pin. |
| Internal Schottky diode | Removes external 20V/0.5A Schottky (e.g., BAT54), reducing BOM count by one component and saving ~1.5mm² PCB area. |
| Presettable startup brightness | Enables factory-set default brightness (e.g., level 6) before first enable, avoiding full-brightness flash during power-on sequencing. |
| 16-level linear brightness scale | FB voltage scales linearly from 25mV (level 0) to 250mV (level 15), enabling intuitive microcontroller firmware mapping without lookup tables. |
| UVLO and thermal shutdown | Under-voltage lockout triggers below 1.8V (typical 2.1V); over-temperature shutdown activates at 150°C junction-prevents damage under fault conditions. |
Applications
| Mobile Handsets | LCD Handset Backlighting |
|---|---|
Use Scenario: Powering 4–6 white LEDs in slim smartphone displays with battery voltage varying from 4.2V (full) to 3.0V (discharged). IC Role / Device Role / Timing Role: Constant-current boost controller regulating LED current independent of input voltage sag and LED Vf drift. Use Value: Maintains consistent display luminance across battery discharge cycle using only 250mV FB reference and 1.2MHz switching for minimal capacitor size. |
Use Scenario: Driving edge-lit LCD backlight in feature phones with space-constrained 2-layer PCB. IC Role / Device Role / Timing Role: Single-wire digital dimming interface replaces PWM trace routing and MCU timer resource allocation. Use Value: Reduces system-level component count by eliminating external Schottky diode and simplifies firmware with 16-step linear control instead of logarithmic PWM duty-cycle tuning. |
| Digital Cameras | Portable Media Players |
Use Scenario: Flash-assist illumination during low-light image capture using short-duration high-current LED bursts. IC Role / Device Role / Timing Role: Fast-startup (140µs turn-on delay) and programmable brightness enable rapid response to camera shutter command. Use Value: Enables immediate full-brightness activation without warm-up delay, supported by 1200mA switch current headroom for transient overdrive. |
Use Scenario: Backlight control in MP3 players with user-adjustable brightness via mechanical button press. IC Role / Device Role / Timing Role: One-step brightness change protocol (tMODE_DOWN + tPROG_HIGH) translates single button press into deterministic level decrement. Use Value: Eliminates firmware state tracking of counter direction-each press reliably decrements brightness regardless of prior mode. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current boost LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX16832ATA+T | Higher 2.1MHz switching frequency; requires external Schottky diode; 200mV FB reference; no single-wire interface-uses analog dimming or PWM input. | Better suited for ultra-compact designs needing <1µH inductors; lacks integrated digital control, requiring additional MCU GPIO or DAC. | Select when board space is critical and digital interface is already handled externally; avoid if replacing MIC3291-25YML-TR's single-wire simplicity. |
| TPS61165DRVR | 1.2MHz operation; internal MOSFET (not bipolar); 200mV FB; I²C interface (not single-wire); 28V OVP option; no preprogrammable startup level. | Supports higher efficiency at light loads due to MOSFET switch; requires I²C bus and address configuration; no native pulse-based brightness preset. | Prefer for systems with existing I²C infrastructure and need for dynamic OVP adjustment; not drop-in for single-wire firmware or preset workflows. |
Compared with MAX16832ATA+T and TPS61165DRVR, the MIC3291-25YML-TR uniquely combines internal Schottky diode, true single-wire digital control with presettable startup, and 25V OVP in a 2mm × 2mm MLF package-enabling lowest BOM count and simplest firmware integration for portable LED backlighting.
Availability
MIC3291-25YML-TR is available at Aetrix Electronics and suitable for mobile handsets, LCD backlighting, digital cameras, and portable media players requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MIC3291-25YML-TR 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
Micrel Inc. was a U.S.-based analog and mixed-signal semiconductor company specializing in power management, LED drivers, and timing solutions before its acquisition by Microchip Technology in 2015.
The MIC3291 family was designed specifically for space-constrained portable backlighting applications demanding high integration, low quiescent current, and simplified digital dimming-targeting smartphones, cameras, and handheld consumer electronics.
FAQ
What is the exact over-voltage protection threshold for MIC3291-25YML-TR?
The MIC3291-25YML-TR has a nominal over-voltage protection threshold of 25V, with guaranteed range 22.1V to 25V across temperature and process variation. This protects the LED string against open-circuit failure when driving up to six-series white LEDs, and is factory-trimmed-no external components affect this value. The MIC3291-25YML-TR does not support adjustable OVP; only the -18V variant offers 18V OVP.
Can MIC3291-25YML-TR drive six white LEDs from a 3.6V supply?
Yes, the MIC3291-25YML-TR can drive six white LEDs from a 3.6V supply. With typical forward voltage of 3.5V per LED (21V total), the 25V OVP margin provides safe headroom. The 1.2MHz boost topology efficiently steps up voltage using a 10µH inductor and achieves >85% efficiency at 20mA per string, as verified in the datasheet's typical characteristics plots for 6-series LED configurations.
How does the single-wire interface of MIC3291-25YML-TR differ from standard PWM dimming?
Unlike standard PWM dimming-which requires continuous MCU-generated square wave-the MIC3291-25YML-TR uses edge-triggered pulses on the DC pin to set brightness level, mode, or shutdown state. Once configured, it holds the setting autonomously ("set-and-forget"), freeing MCU resources. Each pulse width is tightly specified (e.g., tMODE_UP: 100–160µs), and the MIC3291-25YML-TR ignores the first pulse in a sequence to prevent accidental mode changes.
What is the thermal performance of MIC3291-25YML-TR in the MLF-8L package?
The MIC3291-25YML-TR in the 2mm × 2mm MLF-8L package has a junction-to-ambient thermal resistance (θJA) of 93°C/W when mounted on a standard 4-layer PCB with 1in² copper pour under the exposed pad. At 500mA switch current and 3.6V input, typical power dissipation is <350mW, resulting in ≤33°C junction rise above ambient-well within the −40°C to +125°C operating range without forced airflow.
Does MIC3291-25YML-TR require an external Schottky diode?
No, the MIC3291-25YML-TR integrates a Schottky diode with 0.8–1.0V forward drop at 150mA and <4µA leakage at 30V. This eliminates the need for an external diode, reducing BOM count, PCB area, and potential layout errors. The internal diode is rated for the device's full 25V OVP and 1.2A peak switch current, and is electrically verified in all MIC3291-25YML-TR production lots per datasheet specifications.
MIC3291-25YML-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-VFDFN Exposed Pad, 8-MLF®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 2.5V
- Voltage - Supply (Max):
- 6.5V
- Voltage - Output:
- -
- Current - Output / Channel:
- 1.2A (Switch)
- Frequency:
- 1.2MHz
- Dimming:
- -
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MLF® (2x2)
MIC3291-25YML-TR FAQ
1.How can I place an order for MIC3291-25YML-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC3291-25YML-TR 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 MIC3291-25YML-TR reliable?
The price and inventory of MIC3291-25YML-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC3291-25YML-TR is usually 5 days.
3.What payment methods are accepted for MIC3291-25YML-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC3291-25YML-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC3291-25YML-TR?
MIC3291-25YML-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC3291-25YML-TR 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 MIC3291-25YML-TR?
For technical support, including MIC3291-25YML-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC3291-25YML-TR requirements.
6.How does Aetrix verify that MIC3291-25YML-TR is sourced from the original manufacturer or authorized distributors?
All MIC3291-25YML-TR 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 MIC3291-25YML-TR meets industry standards.
7.What is the process for return or replacement of MIC3291-25YML-TR?
All MIC3291-25YML-TR units undergo pre-shipment inspection (PSI). If there is an issue with MIC3291-25YML-TR, 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 MIC3291-25YML-TR part is unused and in its original packaging.
Return procedure for MIC3291-25YML-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MIC3291-25YML-TR Tags
-
BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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