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Microchip Technology MIC3172YM-TR
- Part No.:
- MIC3172YM-TR
- Manufacturer:
- Microchip Technology
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MIC3172YM-TR.pdf
- Description:
- IC REG BUCK BOOST 1.25A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,215
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Product details
Overview
MIC3172YM-TR from Microchip Technology is a 100 kHz current-mode PWM controller IC with integrated 65 V / 1.25 A NPN power switch, designed for step-up, step-down, inverting, and flyback topologies. It operates from 3 V to 40 V input, delivers up to 50 W with external switch, and features TTL-compatible enable (EN) pin, 7 mA operating quiescent current, and <1 µA shutdown current - ideal for battery-powered handheld instruments and compact off-line converters.
For engineers reviewing the MIC3172YM-TR datasheet, MIC3172YM-TR pinout, MIC3172YM-TR application, or MIC3172YM-TR equivalent, key selection criteria include its dedicated EN control logic, dual power ground pins (PGND1/PGND2), internal cycle-by-cycle current limiting, floating switch architecture enabling topology flexibility, and compatibility with LT1172 sockets in legacy designs.
Technical Context
The MIC3172YM-TR implements current-mode control using an internal transconductance error amplifier (3.9 µA/mV typical gain), 1.24 V precision reference, and 100 kHz oscillator with 89% typical maximum duty cycle. Its anti-saturation circuitry extends usable duty range by reducing Q1 turn-off delay via integrated diode D1.
It integrates two separate emitter terminals (PGND1 and PGND2) tied to internal 0.3 Ω current sense resistors; leaving PGND1 unconnected reduces current limit by 50%. The EN pin accepts TTL-low (≤0.4 V) for shutdown and draws ≤1 µA leakage current when disabled.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Rating | 65 V breakdown voltage, 1.25 A continuous current limit at 50% duty cycle - supports robust operation in 40 V input systems with margin. |
| Input Voltage Range | 3.0 V to 40 V - enables direct use across single-cell Li-ion to industrial 24 V rails without pre-regulation. |
| Oscillator Frequency | 88–112 kHz (typ. 100 kHz) - fixed-frequency operation simplifies EMI filtering and magnetics design. |
| Quiescent Current | 7 mA (operating), <1 µA (shutdown) - critical for battery runtime extension in portable devices. |
| Feedback Reference | 1.240 V ±24 mV - sets output voltage accuracy via external resistor divider; line regulation ≤0.07 %/V ensures stability over wide VIN. |
| Enable Threshold | VEN_TH = 0.4–2.4 V - TTL-compatible logic interface allows direct connection to microcontrollers or gate drivers without level shifting. |
| Thermal Resistance | θJA = 120 °C/W (SOIC) - defines junction-to-ambient rise under load; max TJ = +125 °C limits continuous power dissipation. |
Pinout & Package
Package: 8-pin SOIC (YM suffix), rated for –40°C to +85°C ambient operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SGND) | Signal Ground | Analog reference for error amplifier and bias circuits; must be connected directly to input capacitor ground, isolated from power grounds to prevent noise coupling. |
| 2 (COMP) | Error Amplifier Output | Transconductance-type compensation node; used for loop stabilization, soft-start, or current limit tailoring via external RC network. |
| 3 (FB) | Inverting Input of Error Amp | Connects to resistive divider from output; regulates output voltage by comparing against 1.24 V internal reference. |
| 4 (EN) | Enable Control Input | TTL-compatible digital input: high (>2.0 V) enables switching; low (<0.4 V) disables regulator and reduces supply current to <1 µA. |
| 5 (VIN) | Main Supply Input | Power source for internal regulators and driver; accepts 3–40 V DC; minimum start-up voltage is 2.7 V. |
| 6 (PGND2) | Power Ground #2 | Primary emitter connection for internal NPN switch; required connection point for current sensing and thermal path. |
| 7 (VSW) | Switch Collector | High-side collector terminal of internal NPN transistor; connects to inductor or transformer primary in boost/flyback configurations. |
| 8 (PGND1) | Power Ground #1 | Secondary emitter with parallel 0.3 Ω sense resistor; optional connection - floating reduces current limit by 50%. |
Key Features
| Feature | Design Value |
|---|---|
| Dedicated TTL Enable Pin | EN pin provides clean on/off control with sub-µA shutdown current - eliminates need for external MOSFET switches or bias networks in power sequencing. |
| Floating Switch Architecture | Independent VSW, PGND1, and PGND2 terminals allow implementation in boost, buck, inverting, Cuk, and flyback topologies without redesigning PCB layout. |
| Internal Cycle-by-Cycle Current Limit | Hardware-based current protection triggers per-switching cycle - prevents destructive overcurrent events without software intervention or external sensing components. |
| Low External Parts Count | Requires only inductor, diode, output capacitor, and two feedback resistors - reduces BOM cost and board area versus controller+external-FET solutions. |
| LT1172 Socket Compatibility | Pinout matches LT1172 with EN replacing VC pin function - enables drop-in replacement in existing designs with minimal adaptation (e.g., tie EN to VIN if shutdown unused). |
Applications
| Handheld Instruments | Laptop/Palmtop Computers |
|---|---|
Use Scenario: Portable multimeters and oscilloscopes requiring regulated 12 V rail from 3.7 V Li-ion battery. IC Role / Device Role / Timing Role: Primary DC-DC controller managing boost conversion with precise output regulation and low-noise operation. Use Value: 7 mA quiescent current extends battery life; EN pin enables firmware-controlled power cycling during sleep modes. | Use Scenario: USB-C PD adapter auxiliary supply generating 5 V/3.3 V rails from 12–20 V intermediate bus. IC Role / Device Role / Timing Role: Secondary isolated flyback controller delivering isolated bias power to gate drivers and sensors. Use Value: Dual PGND pins simplify current sensing; 65 V switch rating accommodates reflected voltage spikes in flyback transformers. |
| Off-Line Converters | Toys & Consumer Electronics |
Use Scenario: Compact 24 V input, 50 W AC-DC adapter for industrial IoT gateways. IC Role / Device Role / Timing Role: Predriver stage controlling external MOSFETs in active-clamp forward topology. Use Value: Internal 1.25 A switch handles startup and light-load conditions; external FET scales power handling beyond 50 W without changing control IC. | Use Scenario: Battery-powered educational robotics kits needing 9 V output from 4×AA cells (6 V nominal). IC Role / Device Role / Timing Role: Step-up converter IC providing stable motor/sensor supply independent of battery discharge curve. Use Value: 3 V minimum start-up voltage ensures operation down to 0.75 V/cell; <1 µA shutdown current prevents battery drain during storage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1172CS8#PBF | No dedicated EN pin; shutdown achieved by pulling VC pin below 0.15 V - requires external transistor or resistor network. | Legacy socket-compatible but lacks native TTL enable; higher 10 mA quiescent current reduces battery efficiency. | Select LT1172CS8#PBF only when reusing existing VC-control circuitry and EN functionality is unnecessary. |
| TPS61088RHLR | Higher 2.5 A switch rating, 2.7–12 V input, integrated soft-start and OVP - no PGND1/PGND2 separation or LT1172 pin compatibility. | Optimized for single-cell Li-ion boost (e.g., USB power banks); not suitable for 24–40 V industrial inputs or flyback topologies. | Choose TPS61088RHLR for new consumer designs prioritizing integration and safety features over legacy compatibility or wide VIN range. |
Compared with LT1172CS8#PBF, MIC3172YM-TR offers lower quiescent current and simpler enable control; versus TPS61088RHLR, it supports wider input voltage and topology flexibility at the cost of fewer integrated protections.
Availability
MIC3172YM-TR is available at Aetrix Electronics and suitable for handheld instruments, off-line converters, laptop/palmtop computers, and toys requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for MIC3172YM-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
Microchip Technology is a global semiconductor company specializing in microcontrollers, analog devices, and power management ICs, with emphasis on reliability and long-term product availability.
The MIC3172YM-TR belongs to Microchip's legacy high-voltage PWM controller family, engineered for flexible DC-DC conversion in space-constrained, battery-sensitive, and industrial-grade applications where topology adaptability and low standby power are essential.
FAQ
What is the maximum output power achievable with MIC3172YM-TR in boost configuration?
The MIC3172YM-TR supports up to 50 W output power in off-line converter applications when used with an external power switch. With its internal 1.25 A / 65 V NPN switch, typical boost designs deliver ~10–15 W continuously; higher power requires external FETs driven by VSW and PGND nodes. Thermal limits and duty cycle constraints must be verified per Equation 5-1 through 5-5 in the datasheet for each specific layout.
Can MIC3172YM-TR replace LT1172 in existing designs without PCB changes?
Yes - the MIC3172YM-TR is pin-compatible with the LT1172 in 8-pin SOIC packages, with EN replacing the VC pin function. For circuits not using shutdown, connect EN to VIN; for those requiring shutdown, drive EN with a TTL signal. No PCB modification is needed, though minor schematic updates (e.g., removing external shutdown transistor) improve component count and reliability.
How does the dual PGND configuration (PGND1 and PGND2) affect current capability?
PGND2 is mandatory for full 1.25 A current limit; PGND1 is optional. When PGND1 is left unconnected, the internal current sense resistor is effectively doubled, reducing the guaranteed switch current limit by 50% (to ~0.625 A). This allows designers to trade peak power for improved thermal margin or reduced conduction losses in lower-power implementations.
What is the purpose of the anti-saturation diode in MIC3172YM-TR?
The integrated anti-saturation diode (D1) minimizes stored charge between base and collector of the internal NPN switch (Q1), significantly reducing turn-off delay. This extends the usable duty cycle range beyond what standard bipolar processes allow - enabling stable operation in high-duty-ratio topologies like SEPIC or flyback with high turns ratios, where saturation would otherwise cause instability or loss of regulation.
Does MIC3172YM-TR support synchronization with other switching controllers?
No - MIC3172YM-TR lacks a SYNC pin; synchronization capability is exclusive to the MIC2172 variant. The MIC3172YM-TR uses a dedicated EN pin instead. For multi-regulator systems requiring frequency alignment to avoid beat frequencies, designers must select MIC2172 or implement external clock injection via COMP pin modulation - which is not recommended due to loop stability risks and absence of official support in the datasheet.
MIC3172YM-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, Cuk, Flyback, Forward Converter
- Output Type:
- -
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- -
- Voltage - Output (Max):
- -
- Current - Output:
- 1.25A
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MIC3172YM-TR FAQ
1.How can I place an order for MIC3172YM-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC3172YM-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 MIC3172YM-TR reliable?
The price and inventory of MIC3172YM-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC3172YM-TR is usually 5 days.
3.What payment methods are accepted for MIC3172YM-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC3172YM-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC3172YM-TR?
MIC3172YM-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC3172YM-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 MIC3172YM-TR?
For technical support, including MIC3172YM-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC3172YM-TR requirements.
6.How does Aetrix verify that MIC3172YM-TR is sourced from the original manufacturer or authorized distributors?
All MIC3172YM-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 MIC3172YM-TR meets industry standards.
7.What is the process for return or replacement of MIC3172YM-TR?
All MIC3172YM-TR units undergo pre-shipment inspection (PSI). If there is an issue with MIC3172YM-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 MIC3172YM-TR part is unused and in its original packaging.
Return procedure for MIC3172YM-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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