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Diodes Incorporated AP3428WT-7
- Part No.:
- AP3428WT-7
- Manufacturer:
- Diodes Incorporated
- Package:
- SOT-23-5 Thin, TSOT-23-5
- Datasheet:
-
AP3428WT-7.pdf
- Description:
- IC REG BUCK ADJ 1A TSOT25
- Quantity:
- Payment:
- Shipping:
Inventory:183
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Product details
Overview
AP3428WT-7 from Diodes Incorporated is a 1.5MHz, 1A synchronous step-down DC-DC buck converter in TSOT25 (Type SM) package. It operates from 2.5V to 5.5V input, delivers adjustable output from 0.6V to VIN with ±2% reference accuracy, and achieves 40µA no-load quiescent current. Designed for single-cell Li+/Li-polymer and multi-cell alkaline/NiMH power rails, it integrates high- and low-side MOSFETs (RDS(ON) = 250mΩ / 170mΩ) and supports 100% duty cycle for low-dropout operation in portable computing and set-top box power regulation.
For engineers reviewing the AP3428WT-7 datasheet, AP3428WT-7 pinout, AP3428WT-7 application, or AP3428WT-7 equivalent, this page provides verified technical context, validated pin functions, confirmed thermal and electrical specifications, and real-world application constraints - including UVLO (2.4V–2.7V), OTP (+160°C), and hiccup-mode short-circuit protection - essential for battery-powered system design and BOM validation.
Technical Context
The AP3428WT-7 employs constant-frequency PWM control with internal soft-start and no external compensation required. Its synchronous rectification architecture uses integrated PFET and NFET switches with matched RDS(ON) characteristics optimized for efficiency across load range.
Functional block integration includes a 0.6V bandgap reference amplifier, slope-compensated current-mode control, UVLO with 0.1V hysteresis, and cycle-by-cycle overcurrent protection triggered at 1.3A peak inductor current. Shutdown disconnects VIN from VOUT with <1µA leakage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.5MHz fixed - enables compact external LC filter (e.g., 2.2µH + 10µF) and reduces output ripple in space-constrained PCB layouts. |
| Input Voltage Range | 2.5V to 5.5V - supports direct regulation from single Li+/Li-polymer cells (3.0–4.2V) and 3× alkaline/NiMH (4.5V nominal). |
| Output Voltage Range | 0.6V to VIN - adjustable via resistor divider; 0.6V reference with ±2% tolerance ensures ±12mV accuracy at 1.2V output. |
| Max Output Current | 1A continuous - sustained under thermal limits (θJA = 220°C/W in TSOT25) with internal OCP limiting peak inductor current to 1.3A. |
| Quiescent Current | 40µA typical at no load - extends battery runtime in always-on subsystems such as standby logic or sensor bias rails. |
| Shutdown Current | <1µA - isolates input from output during deep sleep, preventing battery drain in host-controlled power sequencing. |
| RDS(ON) (HS/Low-Side) | 250mΩ / 170mΩ - minimizes conduction loss at 1A, enabling >90% efficiency at mid-load (e.g., 5V→3.3V @ 500mA). |
Pinout & Package
AP3428WT-7 is packaged in TSOT25 (Type SM), a 5-pin, 2.92mm × 2.80mm × 0.75mm surface-mount package with exposed pad for thermal enhancement and moisture sensitivity level 3 (J-STD-020).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (EN) | Enable control input | Active-high logic: ≥1.5V enables regulation; ≤0.4V forces shutdown with <1µA supply current. |
| 2 (GND) | Power ground reference | Common return path for internal control circuitry, error amplifier, and power stage - must be low-impedance connection to PCB ground plane. |
| 3 (LX) | Switch node | Drain connection of internal high- and low-side MOSFETs - requires tight layout to minimize EMI and ringing; connects directly to inductor. |
| 4 (VIN) | Main power input | Bias supply for internal regulators and gate drivers - requires local 10µF ceramic capacitor placed within 2mm of pin. |
| 5 (FB) | Feedback voltage input | Connects to resistor divider output; internal 0.6V reference sets VOUT = 0.6V × (1 + R1/R2); FB leakage <0.2µA preserves accuracy. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous power stage | Eliminates external diode and reduces conduction loss - enables >92% peak efficiency at 5V→1.8V/1A without heatsinking. |
| 100% duty cycle operation | Supports VOUT ≈ VIN - critical for low-dropout applications like post-regulation of Li+ battery (3.0V→2.8V) with minimal voltage headroom. |
| Pulse-skip mode at light load | Maintains >80% efficiency down to 10mA load - avoids linear regulator inefficiency while preserving low-noise output for sensitive analog circuits. |
| Internal soft-start (2ms) | Prevents inrush current and output overshoot during power-up - eliminates need for external timing capacitor or sequencer coordination. |
| Comprehensive protection suite | UVLO (2.4V threshold), thermal shutdown (+160°C), hiccup-mode SCP, and cycle-by-cycle OCP - enables robust operation in unattended embedded systems. |
Applications
| Portable Notebook Core Rail | Set-Top Box SoC Power |
|---|---|
|
Use Scenario: Regulating 5V rail to 1.2V core voltage for ARM-based application processors in fanless notebooks. IC Role / Device Role / Timing Role: Primary synchronous buck controller delivering 1A continuous current with fast transient response to CPU DVFS events. Use Value: 40µA quiescent current extends battery life during idle; 100% duty cycle maintains stable 1.2V output as battery discharges from 4.2V to 3.0V. |
Use Scenario: Generating 3.3V I/O supply from 5V main rail in digital broadcast receivers with HDMI and USB interfaces. IC Role / Device Role / Timing Role: Secondary buck converter with pulse-skip mode ensuring low-noise 3.3V for PHY layers during standby and active states. Use Value: 1.5MHz switching frequency allows use of small 2.2µH inductors and 10µF ceramic capacitors - reducing board area by >30% vs. lower-frequency alternatives. |
| USB-Powered Portable Monitor | Smart Home Hub MCU Supply |
|
Use Scenario: Converting 5V USB-C PD input to 1.8V for display driver ICs and touch controller in compact monitors. IC Role / Device Role / Timing Role: High-efficiency step-down regulator operating across full USB voltage range (4.75–5.25V) with tight output tolerance. Use Value: ±2% feedback reference and internal compensation ensure ±18mV output stability over temperature and line/load variations - meeting display IC VDD requirements. |
Use Scenario: Providing clean 3.3V supply to wireless MCU (Wi-Fi/BLE) and sensors in battery-backed smart home hubs. IC Role / Device Role / Timing Role: Always-on buck converter with ultra-low shutdown current (<1µA) minimizing self-discharge of backup coin cell. Use Value: Thermal shutdown (+160°C) and hiccup-mode SCP prevent fault propagation during accidental short-circuit on sensor bus - enhancing field reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2153GQ-Z (Monolithic Power) | 2MHz switching frequency, 0.8V reference, 2.5V–5.5V input, 1A rating, QFN-8 (2mm×2mm) | Higher frequency enables smaller magnetics but increases EMI risk; lacks 100% duty cycle mode. | Select when board space is constrained and 2MHz operation aligns with system noise budget - verify thermal performance in TSOT25 vs. QFN-8. |
| TPS62231DRVR (Texas Instruments) | 3MHz frequency, 0.6V reference, 2.05V–6V input, 0.6A max, WSON-6 (2mm×2mm) | Lower current rating and higher minimum input limit restrict use to sub-600mA loads; superior light-load efficiency via DCS-Control. | Choose only for <600mA applications requiring tighter output accuracy (±1%) and faster transient response - not suitable for 1A continuous loads. |
Compared with MP2153GQ-Z and TPS62231DRVR, AP3428WT-7 uniquely combines 1A capability, 100% duty cycle, and TSOT25 footprint - making it optimal for cost-sensitive, battery-powered designs where dropout headroom and thermal simplicity outweigh the need for ultra-high switching frequencies or sub-1% reference tolerance.
Availability
AP3428WT-7 is available at Aetrix Electronics and suitable for portable notebook core rails, set-top box SoC power supplies, and USB-powered display modules requiring stable component supply, long-term lifecycle support, and RoHS/Green compliance.
Supply support for AP3428WT-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-efficiency power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.
The AP3428/A series belongs to Diodes' high-density DC-DC converter product line, engineered specifically for space-constrained, battery-operated devices requiring low quiescent current, wide input range, and integrated protection - targeting portable computing, digital entertainment, and IoT edge nodes.
FAQ
What is the maximum junction temperature and thermal shutdown behavior of AP3428WT-7?
The AP3428WT-7 features over-temperature protection that triggers at +160°C junction temperature, disabling the internal control circuit and power MOSFETs. Recovery occurs automatically when junction temperature falls to +145°C, initiating internal soft-start. This hysteresis prevents thermal cycling and ensures safe operation under sustained overload or poor PCB thermal design.
Does AP3428WT-7 require external compensation components?
No. The AP3428WT-7 uses an internally compensated current-mode control architecture that eliminates the need for external compensation networks. This simplifies design, reduces BOM count, and improves consistency across production units - confirmed in the functional block diagram and "No External Compensation Required" feature list of DS37417 Rev. 5-2.
How does the enable (EN) pin interface with microcontroller GPIOs?
The EN pin accepts standard 1.8V/3.3V/5V logic levels: voltage ≥1.5V enables regulation, while ≤0.4V forces shutdown with <1µA supply current. Its leakage current is ±1.0µA at 5V, allowing direct connection to most MCU GPIOs without pull-up/down resistors - verified in Electrical Characteristics table (IEN specification).
Can AP3428WT-7 operate with input voltage equal to desired output voltage?
Yes. AP3428WT-7 supports 100% duty cycle operation, enabling VOUT = VIN - critical for maintaining regulated output as battery voltage declines (e.g., 3.6V → 3.3V). This behavior is explicitly documented in the Features section and confirmed by the "Output Voltage: 0.6V to VIN" specification.
AP3428WT-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOT-23-5 Thin, TSOT-23-5
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 1A
- Frequency - Switching:
- 1.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-25
AP3428WT-7 FAQ
1.How can I place an order for AP3428WT-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for AP3428WT-7 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 AP3428WT-7 reliable?
The price and inventory of AP3428WT-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP3428WT-7 is usually 5 days.
3.What payment methods are accepted for AP3428WT-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP3428WT-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP3428WT-7?
AP3428WT-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP3428WT-7 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 AP3428WT-7?
For technical support, including AP3428WT-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP3428WT-7 requirements.
6.How does Aetrix verify that AP3428WT-7 is sourced from the original manufacturer or authorized distributors?
All AP3428WT-7 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 AP3428WT-7 meets industry standards.
7.What is the process for return or replacement of AP3428WT-7?
All AP3428WT-7 units undergo pre-shipment inspection (PSI). If there is an issue with AP3428WT-7, 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 AP3428WT-7 part is unused and in its original packaging.
Return procedure for AP3428WT-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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