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Diodes Incorporated AP3421ADNTR-G1
- Part No.:
- AP3421ADNTR-G1
- Manufacturer:
- Diodes Incorporated
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
AP3421ADNTR-G1.pdf
- Description:
- IC REG BUCK ADJ 1A DL 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,668
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Product details
Overview
AP3421ADNTR-G1 from BCD Semiconductor is a dual-channel synchronous step-down DC-DC converter IC with integrated high-side and low-side MOSFETs, delivering up to 1.0A per output at adjustable voltages (VO1: 1.8–3.6V; VO2: 1.0–3.6V), operating at a fixed 1.3MHz switching frequency with 180° phase shift between channels, and featuring internal soft-start, power-on reset (POR), and discharge-before-turn-on sequencing-used in multi-rail power systems for set-top boxes and hard disk drives.
For engineers reviewing the AP3421ADNTR-G1 datasheet, AP3421ADNTR-G1 pinout, AP3421ADNTR-G1 application, or AP3421ADNTR-G1 equivalent, key selection considerations include dual-output sequencing control, 1.3MHz fixed-frequency operation with pulse-skipping at light load, 10µA shutdown current, open-drain POR monitoring of FB1/FB2/VMON, and DFN-3×3-10 package thermal performance (θJA = 33°C/W).
Technical Context
The AP3421ADNTR-G1 implements two independent current-mode synchronous buck regulators with internal compensation, each supporting resistor-programmable output voltage via FB1/FB2 feedback pins. The 180° phase-shifted switching reduces input ripple and eases EMI filtering requirements.
It integrates peak over-current protection (1.2–1.6A per channel), thermal shutdown (160°C), and under-voltage lockout (2.4–3.0V for AP3421A), with controlled power-up sequencing where VO1 initiates soft-start before VO2, and POR asserts low on any monitored rail drop below threshold (e.g., FB1 falling to 89% of VFB).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 1.0A per channel - supports dual-rail loads like SoC core + I/O rails without external current boosting. |
| Switching Frequency | 1.3MHz fixed - enables compact LC filter design with 3.3µH inductors and 10µF ceramic capacitors. |
| Feedback Voltage | 1.0V ±2.5% - sets precise output regulation accuracy across temperature and line/load variations. |
| Shutdown Current | <10µA - ensures ultra-low quiescent power in battery-backed or always-on standby modes. |
| Thermal Shutdown | 160°C with 10–30°C hysteresis - prevents latch-up during sustained overload while allowing safe recovery. |
| POR Threshold | FB1/FB2: 89% of VFB; VMON: 1.00V - provides robust system-level reset signaling for downstream logic. |
| Input Voltage Range | 3.0–5.5V - compatible with 3.3V and 5V intermediate bus architectures in consumer electronics. |
Pinout & Package
AP3421ADNTR-G1 is housed in a thermally enhanced DFN-3×3-10 package with exposed thermal pad (pin 5 PGND), supporting PCB heat dissipation and meeting RoHS/Green compliance (G1 suffix). Pin numbering follows top-view orientation with pin 1 marked.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 FB2 | VO2 feedback input | Connects to voltage divider on VO2 output side - sets regulated VO2 voltage with 1.0V reference. |
| 2 AVIN | Analog power supply | Provides clean bias for internal analog circuitry; requires 1µF ceramic capacitor to AGND. |
| 3 PVIN | Power switch supply | High-current input for MOSFET drivers; requires 10µF ceramic capacitor to PGND near IC. |
| 4 SW2 | VO2 synchronous switch node | Drives VO2 inductor; connects directly to high-side/low-side MOSFET drains/sources. |
| 5 PGND | Power ground return | Star grounding point for all power paths - critical for noise immunity and thermal performance. |
| 6 SW1 | VO1 synchronous switch node | Drives VO1 inductor; operates 180° out-of-phase with SW2 to reduce input ripple. |
| 7 E/S | Enable/synchronization input | Static high enables operation; static low disables (10µA IQ); external clock syncs at ½ fE/S. |
| 8 POR | Open-drain power-on reset output | Pulls low if FB1, FB2, or VMON drops below threshold; Hi-Z during normal operation. |
| 9 VMON | External voltage monitor input | Monitors auxiliary rail (e.g., VIN); triggers POR when falling below 1.00V threshold. |
| 10 FB1 | VO1 feedback input | Connects to voltage divider on VO1 output side - sets regulated VO1 voltage with 1.0V reference. |
Key Features
| Feature | Design Value |
|---|---|
| Discharge-Before-Turn-On | Forces full discharge of VO1/VO2 before soft-start - ensures reliable sequencing after POR or restart. |
| 180° Phase-Shifted Switching | Reduces RMS input current ripple by ~30% vs. in-phase operation - lowers input capacitor stress. |
| Internal Soft-Start | 1.0ms typical ramp time - limits inrush current and prevents overshoot beyond ±1% of target voltage. |
| Light-Load Pulse Skipping | Automatically enters PSM mode below ~200mA load - improves efficiency at standby without external control. |
| Open-Drain POR Monitoring | Simultaneously watches FB1, FB2, and VMON - delivers system-level reset signal with deglitched assertion. |
Applications
| Set-Top Box Power Management | Hard Disk Drive Dual-Rail Supply |
|---|---|
|
Use Scenario: Powers SoC core (1.2V) and interface I/O (2.5V) from single 5V input in compact STB designs. IC Role / Device Role / Timing Role: Dual synchronous buck regulator providing sequenced, low-noise, high-efficiency DC-DC conversion with POR coordination. Use Value: Eliminates need for discrete sequencing ICs; 1.3MHz operation allows small 3.3µH inductors and 10µF ceramics. |
Use Scenario: Supplies HDD spindle motor driver (3.3V) and servo controller (1.8V) from 5V bus with tight start-up timing. IC Role / Device Role / Timing Role: Dual-output PMIC with VO1-first soft-start and discharge-before-turn-on to prevent backfeed during power cycling. Use Value: Ensures safe spin-up sequence and avoids voltage reversal on shared bus lines during hot-plug events. |
| Industrial Camera Sensor Bias | Embedded Network Router Core/I/O Rails |
|
Use Scenario: Generates clean 2.8V analog sensor bias and 1.2V digital logic rail from 3.3V intermediate supply in low-noise imaging modules. IC Role / Device Role / Timing Role: Dual buck converter with 180° phase shift minimizing conducted EMI into sensitive analog front-end circuits. Use Value: Reduces input ripple-induced noise coupling; POR monitors both rails to halt image capture on undervoltage. |
Use Scenario: Delivers 1.1V CPU core and 3.3V PHY interface voltages in space-constrained network edge devices. IC Role / Device Role / Timing Role: Compact dual-regulator with E/S pin enabling synchronization to system clock domain for deterministic EMI placement. Use Value: Enables co-location of switching noise with less-sensitive clock edges - simplifies FCC/CE compliance testing. |
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 |
|---|---|---|---|
| MP2491DS-LF-Z (Monolithic Power) | Fixed 1.2V/3.3V outputs; no resistor programming; 2.2MHz switching; no POR or VMON pin. | Lacks programmability and system monitoring - suitable only for fixed-voltage, non-critical sequencing use cases. | Choose when board space is tighter and output voltages are invariant; avoid if POR or sequencing control is required. |
| TPS65261RHBR (Texas Instruments) | Dual 1.5A/1.5A outputs; integrated LDO; I²C programmability; 2.25MHz; larger QFN-32 package. | Higher integration but significantly larger footprint and cost - targets high-end industrial, not consumer STB/HDD. | Prefer for designs needing dynamic voltage scaling or multi-rail coordination via I²C; not cost-optimized for AP3421A's segment. |
Compared with MP2491DS-LF-Z and TPS65261RHBR, AP3421ADNTR-G1 offers resistor-programmable outputs, integrated POR/VMON supervision, and DFN-3×3-10 compactness - making it optimal for cost-sensitive, space-constrained dual-rail consumer applications requiring robust power sequencing.
Availability
AP3421ADNTR-G1 is available at Aetrix Electronics and suitable for set-top box power management, hard disk drive dual-rail supply, and embedded network router core/I/O rail applications requiring stable component supply, RoHS-compliant green packaging, and production-ready DFN-3×3-10 thermal performance.
Supply support for AP3421ADNTR-G1 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
BCD Semiconductor Manufacturing Limited is a Shanghai-based fabless analog IC designer specializing in high-performance power management, LED drivers, and mixed-signal solutions for consumer, industrial, and computing markets.
The AP3421 series belongs to BCD's dual-output synchronous buck regulator product line, engineered specifically for compact, low-cost multi-rail power delivery in set-top boxes, storage devices, and embedded systems with strict thermal and sequencing requirements.
FAQ
What is the minimum input voltage required for AP3421ADNTR-G1 to operate?
The AP3421ADNTR-G1 has an under-voltage lockout (UVLO) threshold of 2.4V (rising edge, typical) for the AP3421A variant. Operation begins only when VIN exceeds this value, and the device remains enabled until VIN falls below 2.1V (2.4V – 0.3V hysteresis). This ensures stable startup from 3.3V intermediate buses without brownout risk.
How does the POR function respond to a drop in VO1 voltage?
When VO1 drops such that FB1 voltage falls below 89% of its 1.0V reference (i.e., ≤0.89V), the POR pin pulls low within 10–40µs. It remains asserted for 10–30ms after the fault clears, then releases to high-impedance state. This delay prevents chatter during marginal voltage recovery and ensures downstream logic resets cleanly.
Can AP3421ADNTR-G1 synchronize to an external clock, and what frequency range is supported?
Yes - applying a square wave to the E/S pin synchronizes both SW1 and SW2 to half the external clock frequency (fSW = 0.5 × fE/S). The lock-in range is 1.5MHz to 3.0MHz, meaning the external clock must be 3.0–6.0MHz to achieve 1.3MHz nominal switching. This enables EMI spread-spectrum alignment in noise-sensitive systems.
What is the purpose of the Discharge-Before-Turn-On feature in AP3421ADNTR-G1?
Discharge-Before-Turn-On actively discharges VO1 and VO2 through internal switches before initiating soft-start. This prevents reverse current flow, eliminates pre-bias startup issues, and guarantees monotonic voltage ramp-up - essential for powering FPGAs, ASICs, or memory that cannot tolerate back-driven outputs during power-up or POR recovery.
AP3421ADNTR-G1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1V, 1.8V
- Voltage - Output (Max):
- 3.6V
- Current - Output:
- 1A
- Frequency - Switching:
- 1.3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
AP3421ADNTR-G1 FAQ
1.How can I place an order for AP3421ADNTR-G1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AP3421ADNTR-G1 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 AP3421ADNTR-G1 reliable?
The price and inventory of AP3421ADNTR-G1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP3421ADNTR-G1 is usually 5 days.
3.What payment methods are accepted for AP3421ADNTR-G1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP3421ADNTR-G1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP3421ADNTR-G1?
AP3421ADNTR-G1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP3421ADNTR-G1 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 AP3421ADNTR-G1?
For technical support, including AP3421ADNTR-G1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP3421ADNTR-G1 requirements.
6.How does Aetrix verify that AP3421ADNTR-G1 is sourced from the original manufacturer or authorized distributors?
All AP3421ADNTR-G1 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 AP3421ADNTR-G1 meets industry standards.
7.What is the process for return or replacement of AP3421ADNTR-G1?
All AP3421ADNTR-G1 units undergo pre-shipment inspection (PSI). If there is an issue with AP3421ADNTR-G1, 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 AP3421ADNTR-G1 part is unused and in its original packaging.
Return procedure for AP3421ADNTR-G1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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