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Microchip Technology MIC2171WT
- Part No.:
- MIC2171WT
- Manufacturer:
- Microchip Technology
- Package:
- TO-220-5
- Datasheet:
-
MIC2171WT.pdf
- Description:
- IC REG BUCK BST ADJ 2.5A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:141
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Product details
Overview
MIC2171WT from Microchip Technology is a 100 kHz current-mode PWM controller IC with an integrated 65V/2.5A NPN power switch, designed for step-up, step-down, inverting, Cuk, and isolated flyback/forward topologies. It operates from 3V to 40V input, delivers up to 50W (with external switch), features internal cycle-by-cycle current limiting, and draws only 7 mA quiescent current - ideal for battery-powered handheld instruments and laptop DC-DC conversion.
For engineers reviewing the MIC2171WT datasheet, MIC2171WT pinout, MIC2171WT application, or MIC2171WT equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, topology-specific implementation guidance, and two confirmed alternative controllers with documented functional trade-offs.
Technical Context
The MIC2171WT implements fixed-frequency (100 kHz ±12 kHz) current-mode control using an internal oscillator, transconductance error amplifier (gm = 3.9 µA/mV), and comparator that compares sensed switch current against COMP voltage. Its floating switch architecture enables flexible topology support without requiring high-side gate drivers.
It integrates a precision 1.24 V bandgap reference, anti-saturation circuitry for extended duty cycle (up to 95%), and internal thermal protection. The COMP pin serves dual roles: loop compensation node and soft-start/current-limit tailoring interface - enabling external RC networks or clamping diodes for dynamic response tuning.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Rating | 65 V breakdown voltage, 2.5 A peak current - supports off-line boost converters up to 50 W and flyback designs with ≤65 V reflected output voltage. |
| Input Voltage Range | 3.0 V to 40 V - enables direct operation from single Li-ion (3.0 V min) to 24 V industrial rails without pre-regulation. |
| Oscillator Frequency | 100 kHz nominal (88–112 kHz over temp) - balances EMI suppression, inductor size, and efficiency for portable and embedded power supplies. |
| Quiescent Current | 7 mA typical at full input range - minimizes standby loss in battery-operated equipment with frequent sleep/wake cycles. |
| Feedback Reference | 1.24 V ±24 mV (–40°C to +85°C) - sets output voltage accuracy via external resistor divider; line regulation <0.6 %/V ensures stable regulation across wide VIN. |
| Max Duty Cycle | 95 % - allows high step-up ratios (e.g., 5 V → 12 V) and accommodates transformer leakage in flyback designs without external duty cycle limiting. |
| Thermal Resistance | 45 °C/W (TO-220 & TO-263) - requires minimal heatsinking for ≤1.3 W total dissipation at 70 °C ambient, per thermal calculations in DS20006355A. |
Pinout & Package
Package: 5-pin TO-220 (T-suffix), tab connected to GND. Ambient operating range: –40°C to +85°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output | Transconductance-type node (175 µA typical output); used for frequency compensation, soft-start (via capacitor to GND), and current limit clamping. |
| 2 - FB | Inverting input of error amplifier | Connects to mid-point of output voltage divider; senses regulated output with 1.24 V reference - determines final VOUT accuracy and stability. |
| 3 - GND | Power and signal ground | Must connect directly to input filter capacitor ground; shared return for internal bias, feedback, and compensation - critical for noise immunity. |
| 4 - SW | Collector of internal NPN switch | High-current switching node (2.5 A peak); connects to inductor (boost), transformer primary (flyback), or buck choke - requires low-inductance layout. |
| 5 - IN | Supply input | Accepts 3–40 V DC; powers internal regulator (2.3 V), reference (1.24 V), and driver - no external bias required. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode control | Eliminates right-half-plane zero in boost/flyback, simplifying compensation; enables inherent cycle-by-cycle current limiting for robust overload protection. |
| Floating switch architecture | Supports step-up, step-down, inverting, Cuk, and isolated topologies without topology-specific IC variants - reduces BOM count across product families. |
| Anti-saturation circuit | Extends usable duty cycle to 95 % by removing stored base charge - avoids secondary breakdown during high-duty operation in flyback or forward converters. |
| Low external component count | Requires only inductor, diode, output capacitor, and two feedback resistors for basic boost - eliminates need for external current sense, gate driver, or timing capacitors. |
| Drop-in compatibility | Fits LT1171/LM2577 TO-220 and TO-263 sockets - enables direct upgrade path with improved 100 kHz frequency (2× LM2577) and tighter VREF tolerance. |
Applications
| Portable Boost Power Supply | Flyback Isolated DC-DC |
|---|---|
|
Use Scenario: Generating 12 V @ 0.25 A from a 5 V USB source in handheld test equipment. IC Role / Device Role / Timing Role: Primary PWM controller and integrated power switch; 100 kHz fixed-frequency timing establishes inductor sizing and EMI profile. Use Value: Eliminates external MOSFET and gate driver; 7 mA quiescent current extends battery life; TO-220 package enables convection cooling without heatsink. |
Use Scenario: Providing isolated 5 V @ 0.5 A from 4–6 V battery input in medical sensor modules requiring reinforced insulation. IC Role / Device Role / Timing Role: Controller for discontinuous-conduction-mode flyback; internal 100 kHz oscillator defines transformer turns ratio and clamp requirements. Use Value: Floating switch enables primary-side regulation; anti-saturation prevents failure from transformer leakage spikes; COMP pin allows voltage clipping for second-breakdown protection. |
| Off-Line Step-Up Converter | Predriver for High-Power SMPS |
|
Use Scenario: 24 V input to 48 V output (≤50 W) for telecom line card biasing, using external MOSFET due to higher voltage requirement. IC Role / Device Role / Timing Role: Current-mode controller predriver; generates gate drive signals synchronized to internal 100 kHz clock and current sensing. Use Value: Internal current limit (2.5 A) protects external FET during startup; FB/COMP interface allows seamless integration with external error amplifiers for precision regulation. |
Use Scenario: Driving a discrete 100 V/10 A MOSFET in a 200 W industrial DC-DC converter where MIC2171WT handles control loop while external switch handles power. IC Role / Device Role / Timing Role: Regulator controller with COMP output driving external gate driver; 100 kHz timing ensures predictable switching loss distribution. Use Value: Transconductance COMP output interfaces directly with gate driver bias networks; internal oscillator eliminates need for external timing components - reducing system footprint. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2577T-12/NOPB | Fixed 12 V output, 52 kHz frequency, no COMP pin access, 3 A switch, wider VIN (3.5–40 V) | Limited to fixed-output boost; no programmable feedback or soft-start; lower frequency increases inductor size | Select when simplicity and fixed 12 V output outweigh need for adjustable VOUT, topology flexibility, or EMI optimization. |
| LT1171CT#PBF | 100 kHz frequency, 3 A switch, 60 V rating, but no anti-saturation circuit, higher IQ (10 mA), different pinout (SW/GND swapped) | Compatible in boost/flyback but requires PCB redesign; lacks duty-cycle extension for high-ratio flyback; less robust under leakage-induced stress | Choose only if legacy LT1171 footprint exists and thermal margin permits higher IQ; verify layout changes for SW/GND swap. |
Compared with LM2577T-12/NOPB, MIC2171WT offers adjustable output and superior EMI control via 100 kHz operation; versus LT1171CT#PBF, it adds anti-saturation and tighter VREF for improved accuracy and reliability in leakage-prone flyback designs - without requiring pinout rework.
Availability
MIC2171WT is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered computing, and isolated medical sensor power supplies requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature.
Supply support for MIC2171WT 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and power management ICs, with emphasis on reliability, longevity, and industrial-grade qualification.
The MIC2171WT belongs to Microchip's legacy high-voltage switching regulator controller family, engineered for flexible DC-DC conversion in space-constrained, battery-sensitive, and isolation-critical applications - particularly where topology adaptability and thermal robustness are prioritized over digital configurability.
FAQ
What is the maximum output power achievable with MIC2171WT in boost configuration?
The MIC2171WT supports up to 50 W in boost topology when used with an external power switch, as stated in its Applications section. With its internal 2.5 A/65 V switch, practical output is limited to ~30 W continuous (e.g., 12 V @ 0.25 A from 5 V input) due to thermal constraints - verified by thermal modeling in DS20006355A showing 1.3 W total dissipation at 70 °C ambient. Exceeding this requires careful heatsinking or external FET use.
Can MIC2171WT be used in a step-down (buck) configuration?
Yes, MIC2171WT can implement step-down conversion using forward or transformer-coupled topologies, as confirmed in its General Description and Section 5.7. Its floating switch architecture allows buck-derived configurations, though non-isolated buck requires additional external components versus dedicated buck controllers. The datasheet explicitly shows a 12 V to 5 V forward converter example using MIC2171WT with tertiary winding reset.
What is the purpose of the COMP pin on MIC2171WT, and how is it used in practice?
The COMP pin on MIC2171WT is the output of its transconductance error amplifier and serves three verified functions: (1) loop compensation via RC network to GND or FB, (2) soft-start via capacitor-to-GND to delay output rise, and (3) current limit tailoring via voltage clamp. Its high output impedance enables easy external control - all demonstrated in Figures 5-1 and 5-2 of DS20006355A with real component values and waveforms.
Does MIC2171WT support discontinuous conduction mode (DCM) in flyback designs?
Yes, MIC2171WT is explicitly designed for DCM flyback operation, as detailed in Sections 5.6 and 5.6.5. The datasheet provides Equations 5-10 through 5-22 to validate DCM feasibility, including duty cycle limits (<0.8), peak primary current calculation (2.04 A), and transformer turns ratio derivation (1.83:1). Its 95 % max duty cycle and anti-saturation circuit ensure reliable DCM behavior even with transformer leakage.
How does MIC2171WT compare to LM2577 in terms of frequency and efficiency?
MIC2171WT operates at 100 kHz - twice the 52 kHz frequency of LM2577 - enabling smaller magnetics and better EMI filtering. Its 7 mA quiescent current is lower than LM2577's typical 10 mA, improving light-load efficiency in battery systems. Electrical Characteristics confirm tighter feedback reference (±24 mV vs. ±50 mV) and lower RSW(ON) (0.37 Ω vs. ~0.5 Ω), contributing to higher full-load efficiency in equivalent boost designs.
MIC2171WT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative, Isolation Capable
- Topology:
- Buck, Boost, Cuk, Flyback, Forward Converter
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- -
- Voltage - Output (Max):
- 65V (Switch)
- Current - Output:
- 2.5A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
MIC2171WT FAQ
1.How can I place an order for MIC2171WT through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC2171WT 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 MIC2171WT reliable?
The price and inventory of MIC2171WT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC2171WT is usually 5 days.
3.What payment methods are accepted for MIC2171WT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC2171WT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC2171WT?
MIC2171WT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC2171WT 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 MIC2171WT?
For technical support, including MIC2171WT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC2171WT requirements.
6.How does Aetrix verify that MIC2171WT is sourced from the original manufacturer or authorized distributors?
All MIC2171WT 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 MIC2171WT meets industry standards.
7.What is the process for return or replacement of MIC2171WT?
All MIC2171WT units undergo pre-shipment inspection (PSI). If there is an issue with MIC2171WT, 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 MIC2171WT part is unused and in its original packaging.
Return procedure for MIC2171WT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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