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Microchip Technology MIC24421YML-TR
- Part No.:
- MIC24421YML-TR
- Manufacturer:
- Microchip Technology
- Category:
- DC DC Switching Controllers
- Package:
- 24-VFQFN Exposed Pad, 24-MLF®
- Datasheet:
-
MIC24421YML-TR.pdf
- Description:
- IC REG CTRLR BUCK 24MLF
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MIC24421YML-TR from Micrel is a 2.5A dual-output synchronous PWM buck regulator IC with internal high-side MOSFETs and external low-side N-channel MOSFET drive capability. It operates at 500kHz switching frequency, supports 4.5V–15V input, delivers adjustable outputs down to 0.7V per channel, and features 180° out-of-phase operation for reduced input ripple-used in FPGA/CPU power supplies requiring precise voltage sequencing.
For engineers reviewing the MIC24421YML-TR datasheet, MIC24421YML-TR pinout, MIC24421YML-TR application, or MIC24421YML-TR equivalent, key selection considerations include its 500kHz fixed-frequency voltage-mode control, programmable current limit (0.5A–2.7A), pre-biased startup support, ramp-controlled soft-start, and integrated power-good signaling for multi-rail sequencing.
Technical Context
The MIC24421YML-TR implements a fixed-frequency voltage-mode PWM architecture with two independent 500kHz channels operating 180° out of phase. Each channel uses an internal 2.5A high-side N-MOSFET and drives an external low-side N-MOSFET via dedicated LSD pins, enabling synchronous rectification and high efficiency across wide duty-cycle ranges.
It integrates dual error amplifiers with 0.7V reference, independent EN/DLY pins for per-channel enable/soft-start (4.7nF–22nF capacitor range), and current sensing via low-side RDS(ON) with adjustable trip point (175–225µA source current). Thermal shutdown activates at 165°C with 22°C hysteresis, and UVLO disables both regulators below 3.6V (rising) with 400mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 500kHz ±20% - enables compact magnetics and predictable EMI profile while balancing efficiency vs. size trade-offs. |
| Input Voltage Range | 4.5V to 15V - supports industrial and telecom supply rails without external pre-regulation. |
| Output Voltage Range | Adjustable down to 0.7V - accommodates modern low-voltage cores (e.g., 0.85V FPGA I/O, 1.0V CPU cores) using standard resistor dividers. |
| Max Output Current | 2.5A per channel - sustains full load on both outputs simultaneously with thermal derating up to +125°C junction. |
| Feedback Reference | 0.700V ±1.4% (686–714mV) - ensures tight output regulation (±0.1% total error over temp/load) for sensitive digital loads. |
| Current Limit Range | 0.5A to 2.7A - set via external sense resistor on CS1/CS2, enabling optimized inductor selection and fault protection tailoring. |
| Power Good Threshold | 90% of nominal VOUT - open-drain PG1/PG2 signals assert when output reaches regulation, enabling reliable rail sequencing. |
| Junction Temp Range | –40°C to +125°C - validated for automotive under-hood and industrial embedded environments with no derating until 125°C. |
Pinout & Package
The MIC24421YML-TR is housed in a thermally enhanced 24-pin 4mm × 4mm MLF® (MicroLeadFrame) package with exposed ePad for PCB-level heat sinking. Pin 1 is marked by z-identifier on the package corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BST1, BST2 | Bootstrap Supply Input | Provides gate drive voltage for internal high-side MOSFETs; requires 0.01µF ceramic cap between BSTx and SWx plus external diode to PVDD. |
| LSD1, LSD2 | Low-Side Driver Output | Drives external N-channel MOSFET gates; supports 4.5V-rated devices only to prevent dV/dt-induced shoot-through. |
| CS1, CS2 | Current Sense Input | Accepts voltage drop across low-side MOSFET RDS(ON); sets current limit threshold via external resistor (0.5A–2.7A range). |
| EN/DLY1, EN/DLY2 | Enable & Soft-Start Control | Per-channel enable with <1µs disable timing; soft-start duration set by 4.7nF–22nF capacitor (1.35V start / 2.4V end thresholds). |
| PG1, PG2 | Power Good Output | Open-drain status signal active high when VOUT ≥90% of target; used for inter-rail sequencing without external logic. |
| FB1, FB2 | Feedback Input | Connects to resistor divider; regulates output to 0.7V reference; bias current <5nA minimizes divider error. |
| SW1, SW2 | Switch Node Output | Source node of internal high-side MOSFET; connects to inductor and external low-side MOSFET drain. |
| VIND1, VIND2 | High-Side Drain Supply | Supplies drain of internal high-side MOSFETs; rated 4.5V–13.2V; separate from main VIN for optimal layout isolation. |
| PVDD | Gate Driver Power Input | 5V supply for internal drivers; must be RC-filtered from AVDD to reduce noise coupling into gate drive paths. |
| AVDD | Internal LDO Output | 5V analog supply for control circuitry; requires 4.7µF ceramic bypass; jumper to VIN if input <6V to avoid dropout. |
| EP | Exposed Thermal Pad | Must be soldered to solid ground plane; primary thermal path-reduces θJA to 35°C/W and θJC to 14°C/W. |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase dual-channel operation | Halves input ripple current amplitude vs. in-phase design-reducing bulk capacitor size and cost in multi-rail systems. |
| Pre-biased output startup | Gradually enables low-side MOSFET conduction during soft-start-prevents uncontrolled boost-mode transients when output is pre-charged. |
| Ramp Control™ soft-start | Internally generated linear ramp on EN/DLY pins eliminates external timing components while ensuring monotonic VOUT rise. |
| Low-side current sensing | Uses external MOSFET RDS(ON) instead of sense resistor-eliminates power loss and board space, improves accuracy at low duty cycles. |
| Output voltage sequencing | PGx outputs directly drive EN/DLYy pins-enables precise turn-on order (e.g., core before I/O) with zero additional ICs or firmware. |
| Wide output capacitance compatibility | Stable with ceramic, polymer, or electrolytic capacitors-no need for minimum ESR, simplifying BOM and layout for cost-sensitive designs. |
Applications
| Baseband Processor Power | FPGA Core & I/O Rails |
|---|---|
Use Scenario: Dual-rail power for LTE/5G baseband processors requiring 1.0V core and 1.8V I/O with strict sequencing and fast transient response. IC Role / Device Role / Timing Role: Primary dual-output DC-DC controller managing independent feedback loops, soft-start timing, and PG-driven sequencing between core and interface supplies. Use Value: 500kHz switching enables small 2.2µH inductors; 2% output tolerance ensures processor stability across temperature; 180° phase shift cuts input capacitor RMS current by ~30%. | Use Scenario: Power delivery to Xilinx Artix-7 FPGA with 0.95V core, 1.8V bank, and 2.5V auxiliary rails-requiring staggered startup and robust overcurrent protection. IC Role / Device Role / Timing Role: Dual-channel buck controller delivering regulated core and I/O voltages; PG1 triggers EN/DLY2 after core reaches regulation. Use Value: Adjustable current limit (0.5A–2.7A) allows matching inductor saturation rating to FPGA peak current; pre-biased startup prevents glitching during hot-swap events. |
| Telecom Line Card Supply | Industrial PLC CPU Module |
Use Scenario: Compact 12V-to-3.3V/5V conversion on dense line cards where thermal headroom is limited and EMI must meet EN55022 Class B. IC Role / Device Role / Timing Role: Dual synchronous buck regulator providing isolated, sequenced outputs with minimal external components and integrated thermal protection. Use Value: 4mm×4mm MLF package with ePad achieves 35°C/W θJA; 500kHz frequency places fundamental EMI beyond critical 30–100MHz band; low-side sensing avoids sense-resistor losses. | Use Scenario: Power management for ARM Cortex-A9-based PLC CPU module operating in –40°C to +85°C ambient with 24V industrial input. IC Role / Device Role / Timing Role: Dual-output step-down controller delivering 1.2V CPU core and 3.3V peripheral supply with extended temperature validation and UVLO hysteresis. Use Value: –40°C to +125°C junction rating ensures reliability at 85°C ambient; 400mV UVLO hysteresis prevents oscillation during brown-out; AVDD jumper option supports 5V input operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2491D-LF-Z | Fixed 500kHz frequency, but lacks independent EN/DLY pins and pre-biased startup; uses internal compensation. | No per-channel soft-start or sequencing control; requires external PG logic for multi-rail coordination. | Select when simplicity and BOM count outweigh sequencing flexibility and startup robustness. |
| TPS54290PWP | 1.2MHz switching, higher 3A per channel rating, but requires external bootstrap diodes and has no low-side sensing. | Higher frequency enables smaller inductors but increases gate drive losses; no built-in current limit programming. | Select when higher current or faster transient response is required, and external current sense resistors are acceptable. |
Compared with MP2491D-LF-Z and TPS54290PWP, the MIC24421YML-TR uniquely combines per-channel sequencing control, pre-biased startup, and low-side RDS(ON) current sensing in a thermally optimized 4mm×4mm package-making it optimal for space-constrained, multi-rail industrial and telecom systems demanding reliability and design simplicity.
Availability
MIC24421YML-TR is available at Aetrix Electronics and suitable for FPGA power supplies, telecom line cards, and industrial PLC modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MIC24421YML-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 analog and mixed-signal semiconductor company founded in 1978 and acquired by Microchip Technology in 2015. It specialized in power management, timing, and interface solutions for industrial and communications markets.
The MIC24421YML-TR belongs to Micrel's high-efficiency synchronous buck regulator product line, designed specifically for multi-output, sequencing-critical applications in FPGA, DSP, and CPU power domains where thermal performance and layout simplicity are paramount.
FAQ
What is the recommended bootstrap capacitor value for MIC24421YML-TR?
The MIC24421YML-TR requires a 0.01µF ceramic capacitor between each BSTx pin and its corresponding SWx pin. This value ensures stable high-side gate drive under all load and input conditions. The capacitor must be placed as close as possible to the pins, and a series resistor (20Ω–60Ω) is recommended on the BSTx line to dampen ringing and reduce switch-node overshoot during high-dV/dt transitions.
Does MIC24421YML-TR support pre-biased output startup?
Yes, the MIC24421YML-TR supports pre-biased output startup. Its control architecture gradually enables the low-side MOSFET conduction in proportion to the EN/DLY ramp voltage, preventing uncontrolled 'open-loop boost' behavior when the output is already charged. This feature is confirmed in the Functional Description section of the official datasheet and is active for both channels independently.
What is the maximum allowable input voltage for MIC24421YML-TR?
The absolute maximum input voltage for MIC24421YML-TR is 16V on the VIN pin, but the recommended operating range is 4.5V to 15V. Exceeding 15V risks violating the 16V absolute maximum rating under transient conditions and may trigger UVLO hysteresis instability. For 12V nominal systems, this provides 3V margin for surge events without requiring external clamping.
Can MIC24421YML-TR operate with ceramic output capacitors only?
Yes, the MIC24421YML-TR is explicitly designed to work with ceramic output capacitors-including low-ESR types-without requiring minimum ESR or damping networks. Its patented compensation scheme stabilizes the loop with only one external RC network per channel (COMPx pin), making it compatible with modern high-capacitance, low-profile MLCC arrays common in space-constrained designs.
How is current limit programmed on MIC24421YML-TR?
Current limit on the MIC24421YML-TR is programmed via external resistors connected from SW1/SW2 to CS1/CS2 pins. The device senses voltage drop across the low-side MOSFET's RDS(ON), compares it to a 175–225µA internal current source × RCS, and initiates hiccup-mode protection when exceeded. The trip point ranges from 0.5A to 2.7A depending on selected RCS value, as defined in the Electrical Characteristics table.
MIC24421YML-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 24-VFQFN Exposed Pad, 24-MLF®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 15V
- Frequency - Switching:
- 500kHz
- Duty Cycle (Max):
- 90%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power Good
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-MLF® (4x4)
MIC24421YML-TR FAQ
1.How can I place an order for MIC24421YML-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC24421YML-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 MIC24421YML-TR reliable?
The price and inventory of MIC24421YML-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC24421YML-TR is usually 5 days.
3.What payment methods are accepted for MIC24421YML-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC24421YML-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC24421YML-TR?
MIC24421YML-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC24421YML-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 MIC24421YML-TR?
For technical support, including MIC24421YML-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC24421YML-TR requirements.
6.How does Aetrix verify that MIC24421YML-TR is sourced from the original manufacturer or authorized distributors?
All MIC24421YML-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 MIC24421YML-TR meets industry standards.
7.What is the process for return or replacement of MIC24421YML-TR?
All MIC24421YML-TR units undergo pre-shipment inspection (PSI). If there is an issue with MIC24421YML-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 MIC24421YML-TR part is unused and in its original packaging.
Return procedure for MIC24421YML-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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