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Microchip Technology MIC38HC43YM-TR
- Part No.:
- MIC38HC43YM-TR
- Manufacturer:
- Microchip Technology
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MIC38HC43YM-TR.pdf
- Description:
- IC REG CTRLR MULT TOPOLOGY 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:8,390
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Product details
Overview
MIC38HC43YM-TR from Micrel is an 8-pin SOIC BiCMOS current-mode PWM controller with 1A peak output drive, 8.4V UVLO startup threshold, 7.6V minimum operating voltage, and 96% maximum duty cycle-designed for high-efficiency off-line and DC-DC power supplies including buck, boost, flyback, and forward converters.
For engineers reviewing the MIC38HC43YM-TR datasheet, MIC38HC43YM-TR pinout, MIC38HC43YM-TR application, or MIC38HC43YM-TR equivalent, this device offers rail-to-rail CMOS outputs, 20ns rise/15ns fall times, 5V trimmed bandgap reference, and pin compatibility with UC3843 for drop-in replacement in legacy designs requiring low start-up current (50µA typical) and reduced operating current (4.0mA typical).
Technical Context
The MIC38HC43YM-TR implements fixed-frequency current-mode control with internal oscillator configured via external RT/CT network, supporting up to 500kHz switching. Its error amplifier features 2.5V feedback threshold, 90dB open-loop gain, and 1MHz unity-gain bandwidth for stable loop compensation.
UVLO hysteresis ensures reliable start-up at 8.4V and hold-on down to 7.6V. The current-sense comparator has 3.0V/V gain and 1V threshold, enabling precise primary-side current limiting. Output stage delivers 1A peak sink/source with 5.5Ω RDS(ON) (low) and 10Ω RDS(ON) (high), optimized for driving N-channel MOSFETs directly.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Drive | 1A peak sink/source enables direct drive of medium-power N-MOSFETs without external buffers |
| UVLO Startup | 8.4V with hysteresis ensures clean power-on sequencing in 9–12V input systems |
| Duty Cycle Max | 96% supports high step-down ratios in buck and flyback topologies |
| Rise/Fall Time | 20ns/15ns (CL = 1nF) reduces switching losses and EMI in high-frequency designs |
| Reference Voltage | 5.00V ±2% bandgap output provides stable bias for feedback networks and sensing circuits |
| Operating Current | 4.0mA typical at 15V supply lowers quiescent power in standby and light-load conditions |
| Start-up Current | 50µA typical allows use with high-value startup resistors, reducing dissipation in offline supplies |
Pinout & Package
Package: 8-pin SOIC (M), body size 4.90mm × 3.90mm × 1.75mm, JEDEC MS-012AC, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (COMP) | Error amplifier output | Connect Type II/III compensation network to stabilize voltage loop |
| 2 (FB) | Feedback input | 2.5V threshold sets output regulation point; connects to optocoupler or resistor divider |
| 3 (ISNS) | Current sense input | Accepts voltage from sense resistor; triggers cycle-by-cycle current limit at ~1V |
| 4 (RT/CT) | Oscillator timing node | External RC sets switching frequency; CT charges/discharges linearly for stable ramp |
| 5 (GND) | Combined analog/power ground | Single-point return for IC core and output stage; requires careful PCB grounding |
| 6 (OUT) | Power output driver | Totem-pole CMOS output drives gate of external N-MOSFET; rail-to-rail swing improves efficiency |
| 7 (VDD) | Analog supply input | 15V nominal supply for controller logic; UVLO monitors this pin for startup |
| 8 (VREF) | 5V reference output | Stable 5V source for biasing feedback circuitry or auxiliary loads up to 20mA |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail CMOS output | Enables full gate drive swing across VDD range (7.6–20V), maximizing MOSFET utilization and minimizing conduction loss |
| Trimmed oscillator discharge current | Reduces frequency drift over temperature and supply voltage, improving stability in wide-input applications |
| Low cross-conduction currents | Minimizes shoot-through risk during switching transitions, enhancing reliability in high-speed operation |
| Ultralow 50µA start-up current | Permits use of >1MΩ startup resistors, cutting dissipation in high-voltage AC-DC front-ends |
| BiCMOS process technology | Combines bipolar precision with CMOS low-power logic, achieving 4mA operating current vs. 10mA+ in bipolar UC384x |
Applications
| AC-DC Adapter | Industrial DC-DC Converter |
|---|---|
|
Use Scenario: 12V/2A isolated flyback supply for industrial I/O modules powered from 85–264VAC. IC Role / Device Role / Timing Role: Primary-side PWM controller generating gate drive for power MOSFET; regulates output via optocoupler feedback to FB pin. Use Value: 8.4V UVLO and 7.6V hold-on enable reliable start-up from bulk capacitor after rectification; 96% duty cycle accommodates wide line variations. |
Use Scenario: 48V-to-12V synchronous buck converter in programmable logic controller (PLC) backplane. IC Role / Device Role / Timing Role: Current-mode controller managing high-side N-MOSFET gate drive and current sensing for cycle-by-cycle protection. Use Value: 1A output drive directly controls 50mΩ MOSFETs; 20ns rise time minimizes switching loss at 300kHz operation. |
| LED Driver Supply | Telecom DC-DC Module |
|
Use Scenario: Constant-current 36V LED string driver using boost topology from 12V battery backup. IC Role / Device Role / Timing Role: Boost controller regulating LED current via ISNS feedback; COMP loop shapes dynamic response to load steps. Use Value: 2.5V FB threshold simplifies current-sense amplifier interface; 5V VREF powers op-amp bias for precision current sensing. |
Use Scenario: 48V-to-3.3V/5A forward converter in telecom shelf management unit with strict efficiency targets. IC Role / Device Role / Timing Role: Primary-side controller synchronizing MOSFET gate drive and current sensing for zero-voltage switching assist. Use Value: Low 4mA operating current extends hold-up time during brownout; rail-to-rail OUT improves gate drive margin at low VDD. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar current-mode PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3843N | Bipolar process; 11mA operating current; 250ns rise time; no rail-to-rail output | Higher dissipation, slower switching, lower efficiency at light loads and low VDD | Legacy design reuse where BiCMOS benefits are not required and thermal budget permits |
| LM3478MM/NOPB | Current-mode controller with integrated 1.25A N-MOSFET driver; 1.25MHz max frequency; different pinout | Supports higher switching frequencies and eliminates external MOSFET; not pin-compatible | New designs targeting compact layout and >500kHz operation where board space is constrained |
Compared with UC3843N and LM3478MM/NOPB, the MIC38HC43YM-TR delivers superior efficiency through BiCMOS low-current operation and fast edge rates, while maintaining UC3843 pinout for seamless migration-without requiring PCB changes in existing 8-pin SOIC footprints.
Availability
MIC38HC43YM-TR is available at Aetrix Electronics and suitable for AC-DC adapters, industrial DC-DC converters, and LED driver supplies requiring stable component supply, long-term lifecycle support, and consistent electrical performance across production batches.
Supply support for MIC38HC43YM-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 semiconductor company specializing in analog, power management, and timing solutions before its acquisition by Microchip Technology in 2015.
The MIC38HC4x family was designed as BiCMOS upgrades to UC384x controllers-targeting high-efficiency, low-noise switched-mode power supplies in industrial, telecom, and consumer applications.
FAQ
What is the UVLO behavior of the MIC38HC43YM-TR?
The MIC38HC43YM-TR features undervoltage lockout with 8.4V startup threshold and 7.6V minimum operating voltage, providing 0.8V hysteresis. This ensures robust start-up from bulk capacitors in offline supplies and prevents erratic operation during brownouts. The UVLO circuit monitors the VDD pin directly, and the MIC38HC43YM-TR remains disabled until VDD exceeds 8.4V, then sustains operation down to 7.6V.
Is the MIC38HC43YM-TR pin-compatible with UC3843?
Yes, the MIC38HC43YM-TR is explicitly pin-for-pin compatible with UC3843 in the 8-pin SOIC package. Pin functions-including COMP, FB, ISNS, RT/CT, GND, OUT, VDD, and VREF-match identically. No PCB modification is needed when upgrading from UC3843 to MIC38HC43YM-TR, delivering immediate efficiency gains via BiCMOS architecture.
What is the maximum switching frequency supported by the MIC38HC43YM-TR?
The MIC38HC43YM-TR supports current-mode operation up to 500kHz, as confirmed in the datasheet's "Features" section and Electrical Characteristics table. Frequency is set by external RT and CT components; typical configurations using 9.09kΩ and 3.3nF yield ~52kHz, but scaling CT downward enables full 500kHz capability with appropriate layout and gate drive considerations.
Does the MIC38HC43YM-TR include an internal 5V reference?
Yes, the MIC38HC43YM-TR provides a trimmed 5.00V ±2% bandgap reference on the VREF pin (Pin 8), rated for up to 20mA output. This reference is used internally for the error amplifier and current-sense comparator, and can also power external circuitry such as optocoupler biasing or feedback amplifiers-reducing need for external regulators.
What is the output drive capability of the MIC38HC43YM-TR?
The MIC38HC43YM-TR delivers 1A peak sink and source current from its OUT pin (Pin 6), with RDS(ON) of 5.5Ω (low) and 10Ω (high) at 200mA test conditions. This enables direct drive of medium-power N-channel MOSFETs in buck, boost, and flyback topologies without external drivers-reducing component count and layout complexity in cost-sensitive designs.
MIC38HC43YM-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
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Buck, Boost, Flyback, Forward Converter
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 7.6V ~ 20V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- 96%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Frequency Control
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MIC38HC43YM-TR FAQ
1.How can I place an order for MIC38HC43YM-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC38HC43YM-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 MIC38HC43YM-TR reliable?
The price and inventory of MIC38HC43YM-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC38HC43YM-TR is usually 5 days.
3.What payment methods are accepted for MIC38HC43YM-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC38HC43YM-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC38HC43YM-TR?
MIC38HC43YM-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC38HC43YM-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 MIC38HC43YM-TR?
For technical support, including MIC38HC43YM-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC38HC43YM-TR requirements.
6.How does Aetrix verify that MIC38HC43YM-TR is sourced from the original manufacturer or authorized distributors?
All MIC38HC43YM-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 MIC38HC43YM-TR meets industry standards.
7.What is the process for return or replacement of MIC38HC43YM-TR?
All MIC38HC43YM-TR units undergo pre-shipment inspection (PSI). If there is an issue with MIC38HC43YM-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 MIC38HC43YM-TR part is unused and in its original packaging.
Return procedure for MIC38HC43YM-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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