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Microchip Technology MIC4680BM
- Part No.:
- MIC4680BM
- Manufacturer:
- Microchip Technology
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MIC4680BM.pdf
- Description:
- IC REG BUCK ADJ 1.3A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,331
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Product details
Overview
MIC4680BM from Micrel is an adjustable-output, 200kHz fixed-frequency buck regulator IC with internal NPN switch, 4V–34V input range, 1.23V feedback reference, and up to 1.3A continuous output current in a power-SOIC-8 package. It delivers high-efficiency step-down conversion for industrial power rails and embedded DC/DC supplies.
For engineers reviewing the MIC4680BM datasheet, MIC4680BM pinout, MIC4680BM application, or MIC4680BM equivalent, key selection criteria include its internally compensated voltage-mode control architecture, thermal shutdown at 160°C, <2µA shutdown current, 93–97% max duty cycle, and compatibility with standard off-the-shelf inductors and Schottky diodes.
Technical Context
The MIC4680BM implements voltage-mode PWM control using a 1.23V bandgap reference and a 200kHz sawtooth oscillator. Its error amplifier compares FB voltage against 1.23V to generate a variable-duty-cycle gate drive signal for the integrated NPN switch.
It features cycle-by-cycle current limiting (1.3–2.5A short-circuit limit), frequency foldback under hard short-circuit conditions (30–100kHz), and thermal shutdown at 160°C. The power-SOIC-8 package integrates pins 5–8 and the die-attach paddle into a single low-θJC thermal path (20°C/W).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 34V - supports wide industrial input rails including 12V, 24V, and 32V systems without pre-regulation. |
| Output Current | Up to 1.3A continuous - sufficient for powering microcontrollers, FPGAs, and analog subsystems from single-stage conversion. |
| Switching Frequency | 180–220kHz typical - enables use of compact 68µH inductors and avoids audible noise while maintaining EMI manageability. |
| Feedback Reference | 1.23V ±1% - sets precise output via external resistor divider; stable over –40°C to +125°C junction temperature. |
| Shutdown Current | <2µA typical - ensures ultra-low standby power in battery-backed or energy-sensitive applications. |
| Thermal Shutdown | 160°C - protects device during overload or poor PCB thermal design; self-recovering after cooldown. |
| Max Duty Cycle | 93–97% - allows operation down to VOUT ≈ VIN − 2.5V, supporting high-step-down ratios like 24V→3.3V. |
Pinout & Package
Package: Power-SOIC-8 (M) with integrated thermal paddle connected to pins 5–8 (GND). Designed for enhanced thermal dissipation (θJA = 63°C/W on 6 cm² ground plane).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SHDN | Logic-level shutdown input | TTL-compatible; logic low (≤0.8V) enables regulator, logic high (≥1.6V) disables it with <2µA quiescent draw. |
| 2 - IN (VIN) | Main unregulated input supply | Accepts 4V–34V; powers internal regulator and switch driver; requires local 15µF/35V ceramic or tantalum bypass. |
| 3 - SW | Switch node output | Emitter of internal NPN transistor; connects directly to inductor and Schottky diode cathode; high dv/dt node requiring tight layout. |
| 4 - FB | Feedback input | Senses output voltage via resistive divider; referenced to 1.23V internal bandgap; must be routed away from SW and L1 to avoid noise coupling. |
| 5–8 - GND | Power and signal ground | All four pins tied internally to thermal paddle; must connect to large copper ground plane for thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated voltage-mode control | Eliminates external compensation network; enables stable operation with 68µH inductor and 220µF output capacitor per Bode plot validation. |
| Power-SOIC-8 thermal architecture | Pins 5–8 and die paddle form unified thermal path; achieves θJC ≈ 20°C/W - 3× better than standard SOIC-8 for same footprint. |
| Frequency foldback under short circuit | Reduces switching frequency to 30–100kHz during hard fault, lowering peak switch stress and improving survivability. |
| Adjustable output from 1.25V | Supports custom voltages (e.g., 1.8V, 2.5V, 3.3V, 5V) using two 1% resistors; formula VOUT = 1.23V × (1 + R1/R2) applies. |
| Cycle-by-cycle current limiting | Provides robust overcurrent protection with 1.3A typical trip level; prevents damage during startup, load dump, or output short. |
Applications
| Industrial DC/DC Point-of-Load Supply | Efficient Pre-Regulator for FPGA/MCU Rails |
|---|---|
|
Use Scenario: Converting 24V factory bus to 3.3V for PLC I/O modules or sensor interface boards operating in ambient temperatures up to +85°C. IC Role / Device Role / Timing Role: Primary buck regulator providing regulated 3.3V/1A output with fast transient response to digital load steps. Use Value: Replaces discrete TO-220 solutions with 30% smaller footprint and eliminates external compensation components. |
Use Scenario: Generating clean 1.8V or 2.5V core voltage for Xilinx Spartan or Microchip PIC32MX from a noisy 5V or 12V system rail. IC Role / Device Role / Timing Role: Adjustable buck converter delivering tightly regulated low-voltage supply with <1% line/load regulation. Use Value: Achieves >85% efficiency at 1A load across input range, reducing heat buildup near thermally sensitive logic devices. |
| Battery-Powered Equipment Power Management | Negative Output Converter (Inverting Buck-Boost) |
|
Use Scenario: Step-down from 9V or 12V Li-ion pack to 5V USB peripheral power in portable test equipment with strict standby current limits. IC Role / Device Role / Timing Role: High-efficiency buck regulator enabling >100-hour standby via <2µA shutdown mode current. Use Value: Extends battery life by minimizing quiescent loss while maintaining fast wake-up response (<10µs enable delay). |
Use Scenario: Generating –5V or –12V from a positive 12V rail for op-amp biasing or RS-232 transceivers in instrumentation systems. IC Role / Device Role / Timing Role: Configured as inverting buck-boost using standard external components per Figure 8. Use Value: Delivers stable negative output without requiring dedicated inverting controller IC or transformer-based topology. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576-ADJ | 52kHz fixed frequency, 3A output, TO-220 or TSSOP package; requires external compensation; higher quiescent current (~5mA active, ~75µA shutdown). | Higher output current but lower switching frequency increases inductor size; less suitable for space-constrained PCBs. | Choose LM2576-ADJ when >1.3A output or legacy TO-220 mounting is required; avoid if 200kHz operation or ultra-low shutdown current is critical. |
| TPS54202DRT | 500kHz adjustable buck, 2A output, 6-pin SOT-23; integrated MOSFETs; requires external compensation; 22µA shutdown current. | Smaller package and higher frequency allow miniaturized designs but lacks built-in thermal protection and has narrower input range (4.5V–28V). | Choose TPS54202DRT for ultra-compact 2A designs where thermal margin is assured; MIC4680BM preferred for rugged industrial environments with wide VIN and thermal shutdown assurance. |
Compared with LM2576-ADJ and TPS54202DRT, the MIC4680BM offers superior thermal protection (160°C shutdown), lowest shutdown current (<2µA), and optimized power-SOIC-8 thermal performance - making it ideal for industrial applications demanding reliability across –40°C to +125°C.
Availability
MIC4680BM is available at Aetrix Electronics and suitable for industrial automation, embedded power management, and battery-powered instrumentation requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for MIC4680BM 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 power IC manufacturer specializing in high-reliability DC/DC regulators, timing devices, and interface solutions before its acquisition by Microchip Technology in 2015.
The MIC4680BM belongs to Micrel's SuperSwitcher™ family of integrated buck regulators, designed specifically for easy-to-use, high-current, wide-input industrial power conversion without external compensation.
FAQ
What is the minimum input voltage required for MIC4680BM to regulate a 3.3V output?
The MIC4680BM requires VIN ≥ VOUT + 2.5V per datasheet Note 4, so minimum input is 5.8V for 3.3V output. However, absolute minimum operating VIN is specified as 4V - meaning 3.3V regulation is only guaranteed above 5.8V. Below that, dropout occurs and output collapses. The MIC4680BM cannot sustain 3.3V output at 4V input.
Can MIC4680BM be used in a synchronous rectification configuration?
No, the MIC4680BM integrates only an NPN bipolar transistor as the main switch and does not support external synchronous MOSFET drive. It relies on an external Schottky diode (e.g., B260A or SS26) for freewheeling. Synchronous operation would require replacing the diode with a MOSFET and adding gate drive timing - which the MIC4680BM does not provide.
What is the recommended output capacitor ESR for MIC4680BM stability?
The MIC4680BM datasheet validates stability with a 220µF/16V aluminum or polymer capacitor (e.g., AVX TPSE227010R0060) and does not specify a minimum ESR. Its internal compensation is optimized for low-ESR capacitors. Using ceramic output caps alone is not recommended due to insufficient ESR; a hybrid approach (e.g., 22µF ceramic + 220µF polymer) maintains phase margin >35° per Bode plot data.
Does MIC4680BM support remote sensing of the output voltage?
No, the MIC4680BM uses single-point feedback via the FB pin and lacks dedicated sense+ and sense– inputs. Remote sensing would require routing FB from the load instead of the regulator output, introducing noise susceptibility and potential instability. For precision remote sensing, a controller with dedicated differential sense inputs (e.g., LTC3775) is required.
How does the MIC4680BM behave during startup when the input voltage ramps slowly?
The MIC4680BM incorporates undervoltage lockout (UVLO) implicitly via its 4V minimum operating VIN. If VIN rises slowly through the 4V threshold, the device begins switching only once VIN exceeds ~4.2V and remains enabled as long as VIN stays above 4V. No soft-start circuitry is integrated - output voltage rises rapidly with inductor current slew rate limited only by L1 and load.
MIC4680BM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- SuperSwitcher™
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 34V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 32.98V
- Current - Output:
- 1.3A
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MIC4680BM FAQ
1.How can I place an order for MIC4680BM through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC4680BM 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 MIC4680BM reliable?
The price and inventory of MIC4680BM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC4680BM is usually 5 days.
3.What payment methods are accepted for MIC4680BM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC4680BM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC4680BM?
MIC4680BM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC4680BM 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 MIC4680BM?
For technical support, including MIC4680BM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC4680BM requirements.
6.How does Aetrix verify that MIC4680BM is sourced from the original manufacturer or authorized distributors?
All MIC4680BM 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 MIC4680BM meets industry standards.
7.What is the process for return or replacement of MIC4680BM?
All MIC4680BM units undergo pre-shipment inspection (PSI). If there is an issue with MIC4680BM, 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 MIC4680BM part is unused and in its original packaging.
Return procedure for MIC4680BM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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