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Allegro MicroSystems APEK4447SLJ-01-T-DK
- Part No.:
- APEK4447SLJ-01-T-DK
- Manufacturer:
- Allegro MicroSystems
- Package:
- Datasheet:
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APEK4447SLJ-01-T-DK.pdf
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Product details
Overview
APEK4447SLJ-01-T-DK from Allegro MicroSystems is a high-voltage, 2 A synchronous step-down (buck) regulator IC with adjustable output (0.8–24 V), 8–50 V input range, integrated 450 mΩ DMOS switch, fixed off-time current-mode control, and SOIC-8LJ package with exposed thermal pad. It delivers stable DC/DC conversion for industrial power rails and POS equipment.
For engineers reviewing the APEK4447SLJ-01-T-DK datasheet, APEK4447SLJ-01-T-DK pinout, APEK4447SLJ-01-T-DK application, or APEK4447SLJ-01-T-DK equivalent, key selection criteria include VIN max (50 V), RDS(on) (450 mΩ @ 25°C), FB reference (0.8 V ±2%), thermal resistance (RθJA = 35 °C/W on 4-layer PCB), and TSET-based off-time programmability.
Technical Context
The APEK4447SLJ-01-T-DK implements fixed off-time, current-mode control with internal blanking (200 ns) to suppress diode reverse-recovery transients. It operates in both continuous and discontinuous conduction modes and enters cycle-skipping at light loads to maintain regulation.
Feedback uses a precision 0.8 V ±2% reference with ≤100 nA bias current; VBIAS supports efficiency optimization by connecting to VOUT when output is 3.3–5 V. ENB enables logic-level on/off control with 1.0 V threshold and <1 µA leakage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 8–50 V - supports wide industrial bus voltages including 12 V, 24 V, 36 V, and 48 V systems |
| Output Current | 2 A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in embedded systems |
| RDS(on) | 450 mΩ @ 25°C - minimizes conduction loss and thermal rise under full load |
| FB Reference | 0.8 V ±2% - enables accurate, stable output voltage setting via external resistor divider |
| Thermal Resistance | RθJA = 35 °C/W (4-layer PCB) - requires minimal heatsinking for 2 A operation at 85°C ambient |
| Off-Time Control | RTSET-programmable (e.g., 54 kΩ → ~100 µs) - sets switching frequency and prevents minimum on-time violation |
| Protection Features | UVLO (6.9 V typ), thermal shutdown (165°C), short-circuit current limit (0.85 A typ when VFB < 0.4 V) - ensures robust field operation |
Pinout & Package
Package: 8-pin SOIC with exposed thermal pad (LJ suffix), JEDEC MS-012BA compliant, 6.00 × 4.90 × 1.73 mm, matte tin-plated leadframe.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - BOOT | Gate drive boost node | Supplies charge pump voltage to high-side switch gate; requires 0.01 µF ceramic capacitor to LX |
| 2 - ENB | Enable/disable logic input | Active-low control: pulled low to enable soft-start; open-circuit disables output and discharges VOUT |
| 3 - TSET | Fixed off-time programming | Resistor-to-GND sets tOFF (e.g., 54 kΩ → ~100 µs); critical for frequency stability and light-load behavior |
| 4 - GND | Power and signal ground | Must connect to large copper pour and thermal vias beneath exposed pad for thermal management |
| 5 - FB | Feedback input | Senses output via resistor divider; 0.8 V reference enables precise VOUT adjustment from 0.8 to 24 V |
| 6 - VBIAS | Bias supply input | Connected to VOUT when 3.3–5 V output is used; improves efficiency vs. drawing bias from VIN |
| 7 - LX | Switching node | Connects to inductor and catch diode anode; high dv/dt node requiring tight layout and ground shielding |
| 8 - VIN | Main power input | Accepts 8–50 V; requires local 0.22 µF + bulk capacitor (e.g., 100 µF/50 V) placed adjacent to pin |
Key Features
| Feature | Design Value |
|---|---|
| Wide input range | 8–50 V operation eliminates need for pre-regulation in 24/36/48 V industrial systems |
| Integrated 450 mΩ switch | Reduces BOM count and board space vs. controller + external MOSFET solutions |
| Adjustable 0.8–24 V output | Single part supports multiple rail voltages (e.g., 1.5 V, 1.8 V, 3.3 V, 5 V, 12 V) via resistor selection |
| Internal 200 ns blanking | Suppresses false triggering from Schottky diode recovery noise without external RC snubbers |
| Exposed thermal pad | Enables RθJP = 2 °C/W path to PCB ground plane - essential for 2 A continuous operation |
Applications
| Printer Power Supplies | POS Terminal Power |
|---|---|
Use Scenario: Provides regulated 3.3 V and 5 V rails for thermal print head drivers, MCU, and communication interfaces in compact receipt printers. IC Role / Device Role / Timing Role: Primary buck regulator delivering 2 A peak current with fast transient response to handle print head pulse loads. Use Value: Eliminates need for discrete FET + controller; 50 V VIN rating accommodates 36 V battery backup inputs without derating. | Use Scenario: Powers 1.8 V FPGA I/O banks and 3.3 V USB/UART peripherals in point-of-sale kiosks operating from 24 V industrial bus. IC Role / Device Role / Timing Role: Adjustable-output DC/DC converter enabling single-BOM support across multiple POS models with varying rail requirements. Use Value: RTSET programmability allows optimization of switching frequency (e.g., ~123 kHz) to avoid EMI bands while maintaining >85% efficiency at 2 A. |
| Industrial PLC I/O Modules | Tape Drive Power Management |
Use Scenario: Generates isolated 5 V and 12 V auxiliary supplies for analog sensor front-ends and relay drivers in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: High-input-voltage buck regulator interfacing directly to 24/48 V backplane, with UVLO preventing brownout-induced resets. Use Value: 150°C junction temperature rating and cycle-skipping light-load mode ensure reliability in unventilated enclosures. | Use Scenario: Supplies 5 V to tape transport motor drivers and servo amplifiers in enterprise backup storage systems with 42 V nominal input. IC Role / Device Role / Timing Role: Main power stage converting 42 V bus to stable 5 V at up to 2 A, with short-circuit protection during tape jam events. Use Value: Internal 0.85 A short-circuit current limit prevents catastrophic failure during mechanical overloads without external current-sense circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MPQ4447GQ-AEC1-P | Automotive-grade (AEC-Q100), 40 V max VIN, 2.5 A rated, QFN-16 package with thermal pad | Requires re-layout due to different pinout and package; suited for automotive infotainment, not industrial | Select only if AEC-Q100 qualification and higher current margin are mandatory; verify thermal performance on target PCB |
| LM5164QPWPRQ1 | 42 V max VIN, 1 A rated, integrated high-side FET, 2.1 MHz fixed-frequency operation | Limited to 1 A output; higher frequency enables smaller magnetics but increases EMI filtering complexity | Choose when board space is constrained and 1 A suffices; not suitable for 2 A industrial loads without parallel design |
Compared with MPQ4447GQ-AEC1-P and LM5164QPWPRQ1, the APEK4447SLJ-01-T-DK offers optimal balance of 50 V input capability, 2 A output, SOIC-8LJ manufacturability, and industrial temperature range - making it ideal for cost-sensitive, high-reliability non-automotive applications where pin compatibility and thermal simplicity are prioritized.
Availability
APEK4447SLJ-01-T-DK is available at Aetrix Electronics and suitable for industrial automation, point-of-sale terminals, and printer power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for APEK4447SLJ-01-T-DK 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
Allegro MicroSystems is a U.S.-based designer and manufacturer of high-performance magnetic sensing and power IC solutions, headquartered in Manchester, NH.
The APEK4447SLJ-01-T-DK belongs to Allegro's high-voltage buck regulator product line, engineered specifically for industrial, computing, and commercial applications demanding robust 8–50 V input conversion with minimal external components.
FAQ
What is the maximum input voltage rating for the APEK4447SLJ-01-T-DK?
The APEK4447SLJ-01-T-DK has an absolute maximum VIN rating of 50 V, with typical operation supported from 8 to 50 V. Its undervoltage lockout activates at 6.9 V (typical), ensuring reliable startup across wide industrial bus voltages. This makes the APEK4447SLJ-01-T-DK well-suited for 24 V and 36 V systems where transient spikes may exceed nominal ratings.
Does the APEK4447SLJ-01-T-DK require an external catch diode?
Yes, the APEK4447SLJ-01-T-DK requires an external Schottky catch diode (e.g., NSQ03A06) connected between LX and GND. It is not a synchronous buck regulator - the internal DMOS switch operates as a high-side FET only, and the diode provides the return path during the off-time. Diode selection must account for 1.2× load current and voltage rating exceeding maximum VIN.
How is the output voltage set on the APEK4447SLJ-01-T-DK?
The output voltage of the APEK4447SLJ-01-T-DK is set using a resistor divider from VOUT to GND, connected to the FB pin. With a precise 0.8 V ±2% internal reference, VOUT = 0.8 V × (1 + R1/R2). For example, R1 = 2.87 kΩ and R2 = 910 Ω yields 3.3 V. Low-impedance dividers (<100 kΩ total) are recommended to minimize noise susceptibility.
What thermal considerations apply to the APEK4447SLJ-01-T-DK in continuous 2 A operation?
For continuous 2 A operation, the APEK4447SLJ-01-T-DK requires its exposed thermal pad to be soldered to a ≥0.8 in² copper area on a 4-layer PCB with ≥6 thermal vias. Under these conditions, RθJA = 35 °C/W enables operation up to 85°C ambient while keeping junction temperature below 150°C. Without adequate copper and vias, derating is necessary per the thermal characteristics table.
Can the APEK4447SLJ-01-T-DK operate with VOUT below 0.8 V?
No, the APEK4447SLJ-01-T-DK cannot regulate below 0.8 V because its internal feedback reference is fixed at 0.8 V ±2%. The minimum output is therefore constrained by this reference voltage - even with R2 = 0, VOUT cannot drop below 0.8 V. For sub-0.8 V outputs, a different regulator architecture (e.g., LDO or current-mode controller with external reference) is required.
APEK4447SLJ-01-T-DK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Main Purpose:
- DC/DC, Step Down
- Outputs and Type:
- 1 Non-Isolated Output
- Voltage - Output:
- -
- Current - Output:
- 0.8V ~ 24V
- Voltage - Input:
- 2A
- Regulator Topology:
- 8V ~ 50V
- Frequency - Switching:
- Buck
- Contents:
- -
- Utilized IC / Part:
- Board(s)
- Power - Output:
- A4447
APEK4447SLJ-01-T-DK FAQ
1.How can I place an order for APEK4447SLJ-01-T-DK through Aetrix?
Please submit a Request for Quotation (RFQ) for APEK4447SLJ-01-T-DK 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 APEK4447SLJ-01-T-DK reliable?
The price and inventory of APEK4447SLJ-01-T-DK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for APEK4447SLJ-01-T-DK is usually 5 days.
3.What payment methods are accepted for APEK4447SLJ-01-T-DK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for APEK4447SLJ-01-T-DK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for APEK4447SLJ-01-T-DK?
APEK4447SLJ-01-T-DK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your APEK4447SLJ-01-T-DK 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 APEK4447SLJ-01-T-DK?
For technical support, including APEK4447SLJ-01-T-DK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your APEK4447SLJ-01-T-DK requirements.
6.How does Aetrix verify that APEK4447SLJ-01-T-DK is sourced from the original manufacturer or authorized distributors?
All APEK4447SLJ-01-T-DK 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 APEK4447SLJ-01-T-DK meets industry standards.
7.What is the process for return or replacement of APEK4447SLJ-01-T-DK?
All APEK4447SLJ-01-T-DK units undergo pre-shipment inspection (PSI). If there is an issue with APEK4447SLJ-01-T-DK, 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 APEK4447SLJ-01-T-DK part is unused and in its original packaging.
Return procedure for APEK4447SLJ-01-T-DK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
APEK4447SLJ-01-T-DK Tags
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DFR0571
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DC2468A
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