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Microchip Technology MIC2171BT
- Part No.:
- MIC2171BT
- Manufacturer:
- Microchip Technology
- Package:
- TO-220-5
- Datasheet:
-
MIC2171BT.pdf
- Description:
- IC REG BUCK BST ADJ 2.5A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,593
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Product details
Overview
MIC2171BT from Microchip Technology is a 100 kHz current-mode PWM controller IC with 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 MIC2171BT datasheet, MIC2171BT pinout, MIC2171BT application, or MIC2171BT equivalent, key selection criteria include its 2.5A peak switch rating, 1.24V feedback reference, 90% max duty cycle, TO-263-5 package thermal performance (θJA = 45°C/W), and compatibility with LT1171/LM2577 socket footprints.
Technical Context
The MIC2171BT implements fixed-frequency (88–112 kHz) current-mode control using an internal 1.24V bandgap reference and transconductance error amplifier. Its floating switch architecture enables flexible topology support without requiring external high-side gate drivers.
It integrates anti-saturation circuitry to extend usable duty cycle, employs internal cycle-by-cycle current limiting with temperature-compensated threshold (2.5–5.5 A), and provides COMP pin functionality for loop compensation, soft-start, and current-limit tailoring via external RC networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Rating | 65V VBR, 2.5A peak - supports off-line boost up to 50W and flyback isolation with ≤65V reflected voltage |
| Input Voltage Range | 3.0V to 40V - enables direct operation from 5V logic rails or 24V industrial supplies |
| Oscillator Frequency | 88–112 kHz (typ. 100 kHz) - twice LM2577 frequency; reduces magnetics size vs. legacy controllers |
| Feedback Reference | 1.240V ±24 mV - precision bandgap reference enabling accurate output regulation across –40°C to +85°C |
| Quiescent Current | 7 mA (typ.) - low standby draw critical for battery life in palmtop/laptop applications |
| Max Duty Cycle | 90% (guaranteed ≥80%) - supports wide input-output ratios in boost and flyback designs |
| Thermal Resistance | θJA = 45°C/W (TO-263-5) - requires ≥2 in² copper pour for reliable 1.3W dissipation at 70°C ambient |
Pinout & Package
Package: 5-pin TO-263 (D2PAK), tab-connected to GND, rated for –40°C to +85°C ambient operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - COMP | Error amplifier output | Transconductance-type node for loop compensation, soft-start capacitor connection, or current-limit clamping |
| 2 - FB | Inverting input of error amplifier | Connects to resistor divider midpoint; senses output voltage with 310–1100 nA bias current |
| 3 - GND | Power and signal ground | Must tie directly to input capacitor ground; single-point grounding required to avoid noise coupling |
| 4 - SW | Collector of internal NPN switch | High-current switching node; connects to inductor (boost/flyback) or transformer primary (forward) |
| 5 - IN | Supply input | Accepts 3–40V DC; powers internal 2.3V regulator and bias circuits; not current-limited |
Key Features
| Feature | Design Value |
|---|---|
| Floating switch architecture | Enables step-up, step-down, inverting, Cuk, and isolated topologies without external level-shifting components |
| Internal cycle-by-cycle current limit | Guarantees 2.5A minimum switch current limit across temperature; prevents destructive overcurrent during startup or fault |
| Anti-saturation diode | Eliminates stored charge delay in internal NPN switch, extending effective duty cycle range beyond typical bipolar limitations |
| Low-component-count design | Requires only inductor, diode, output capacitor, and two feedback resistors - no external MOSFET driver or timing capacitors needed |
| LT1171/LM2577 socket compatibility | TO-263-5 footprint matches industry-standard 5-pin packages - enables drop-in replacement in existing layouts |
Applications
| Laptop DC-DC Boost Converter | Battery-Powered Handheld Instrument |
|---|---|
Use Scenario: Generating stable 12V rail from 5V USB or Li-ion battery (3.0–4.2V) to power analog front-ends and displays. IC Role / Device Role / Timing Role: Primary PWM controller and power switch; regulates output via FB pin; 100 kHz switching sets LC filter size and EMI profile. Use Value: 7 mA quiescent current extends battery runtime; internal 2.5A switch eliminates external transistor, reducing BOM count and board area. | Use Scenario: Portable multimeter or oscilloscope requiring isolated ±5V rails from single 9V alkaline cell. IC Role / Device Role / Timing Role: Flyback controller driving transformer primary; COMP pin used for frequency compensation and soft-start. Use Value: 65V switch rating accommodates reflected voltage spikes; discontinuous conduction mode simplifies feedback loop design for variable load conditions. |
| Off-Line 50W Isolated Supply | Predriver for High-Power SMPS |
Use Scenario: Industrial sensor interface needing reinforced isolation and 24V/2A output from 85–264V AC via bridge rectifier and bulk cap. IC Role / Device Role / Timing Role: Primary-side controller in flyback topology; SW pin drives transformer primary; FB receives optocoupler feedback. Use Value: Internal current limit protects against overload; 90% max duty cycle supports wide line regulation; TO-263 thermal performance sustains continuous 50W output with proper heatsinking. | Use Scenario: Driving external 100V/10A MOSFET in high-efficiency telecom DC-DC brick where precise current sensing is required. IC Role / Device Role / Timing Role: Current-mode predriver generating gate drive signals; COMP output interfaces with external current-sense amplifier. Use Value: Transconductance COMP output allows programmable current foldback; 100 kHz oscillator synchronizes with master clock; internal reference ensures consistent threshold accuracy. |
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 | Fixed 12V output, 3A switch, 52 kHz oscillator, TO-220 only | Limited to step-up; no adjustable feedback or topology flexibility | Select when fixed-output, lower-frequency, cost-sensitive boost is sufficient and layout space permits TO-220 |
| LT1171CT | 100 kHz, 4A switch, wider VIN (3–60V), SO-8 and TO-220 packages | Higher current capability but no TO-263 option; less optimized for flyback duty cycle | Prefer for higher-power step-up or when SO-8 surface-mount is required; verify thermal margin at full load |
Compared with LM2577T-12 and LT1171CT, the MIC2171BT offers unique TO-263-5 packaging with identical socket fit, broader topology support including forward converters, and tighter feedback reference (±24 mV vs. ±50 mV), making it optimal for compact, multi-topology, thermally constrained designs.
Availability
MIC2171BT is available at Aetrix Electronics and suitable for laptop power supplies, battery-operated test equipment, and isolated industrial sensor interfaces requiring stable component supply and long-term production continuity.
Supply support for MIC2171BT 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-life product support.
The MIC2171BT belongs to Microchip's legacy high-voltage switching controller family, engineered for robustness in portable and industrial DC-DC conversion where integration, thermal efficiency, and topology flexibility are critical.
FAQ
What is the maximum output power achievable with MIC2171BT in boost topology?
The MIC2171BT supports up to 50W output in boost configuration when used with an external power switch. With its internal 2.5A/65V switch, practical output is limited by thermal constraints: at 70°C ambient and 45°C/W θJA, total dissipation must stay below ~1.3W, yielding ~12V/0.25A (3W) in self-contained operation. Higher power requires external MOSFET driven by MIC2171BT's SW node.
Does MIC2171BT support synchronous rectification?
No, MIC2171BT does not support synchronous rectification. It is designed to drive a single external diode (e.g., Schottky) in boost/flyback topologies. The internal NPN switch and control architecture lack dedicated gate-drive outputs or timing control for synchronous FETs. For synchronous designs, Microchip's newer MIC24045 or MPQ4312 families are recommended.
Can MIC2171BT operate below 3V input?
No, MIC2171BT has a minimum operating input voltage of 3.0V (typ. 2.7V). Below this, internal biasing fails and regulation ceases. The device will not start or sustain oscillation at 2.5V or lower. For sub-3V applications, consider Microchip's MIC2295 (2.5V min) or external LDO-biasing solutions - but note that MIC2171BT itself cannot function reliably below its specified VIN(MIN).
What is the purpose of the COMP pin on MIC2171BT, and how is it used in practice?
The COMP pin on MIC2171BT is the output of its transconductance error amplifier. It serves three key functions: (1) loop compensation via RC network to GND or FB, (2) soft-start via capacitor-to-ground to limit inrush, and (3) current-limit tailoring via voltage clamp. In all cases, its high output impedance allows easy external control - unlike voltage-mode controllers, COMP voltage directly modulates PWM duty cycle based on sensed current and feedback error.
Is MIC2171BT pin-compatible with MIC2171WT?
Yes, MIC2171BT and MIC2171WT share identical pinout, electrical specifications, and functional behavior. The suffix "BT" denotes TO-263-5 (D2PAK) packaging with tape-and-reel delivery, while "WT" indicates TO-220-5 packaging. Both use the same die, same thermal specs (θJA = 45°C/W), and same marking format per DS20006355A-page 16 - enabling direct mechanical substitution where board layout allows.
MIC2171BT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Bulk
- Product Status:
- Obsolete
- 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
MIC2171BT FAQ
1.How can I place an order for MIC2171BT through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC2171BT 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 MIC2171BT reliable?
The price and inventory of MIC2171BT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC2171BT is usually 5 days.
3.What payment methods are accepted for MIC2171BT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC2171BT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC2171BT?
MIC2171BT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC2171BT 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 MIC2171BT?
For technical support, including MIC2171BT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC2171BT requirements.
6.How does Aetrix verify that MIC2171BT is sourced from the original manufacturer or authorized distributors?
All MIC2171BT 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 MIC2171BT meets industry standards.
7.What is the process for return or replacement of MIC2171BT?
All MIC2171BT units undergo pre-shipment inspection (PSI). If there is an issue with MIC2171BT, 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 MIC2171BT part is unused and in its original packaging.
Return procedure for MIC2171BT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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