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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Diodes Incorporated AP1121ASL-13

Name: AP1121ASL-13
Brand: Diodes Incorporated
SKU: AP1121ASL-13
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AP1121ASL-13

Manufacturer:: Diodes Incorporated

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: AP1121ASL-13.pdf

Description:: IC REG LIN 2.5V/3.3V 1A/1A 8SOP

Quantity:: RFQ Add To RFQ list

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Inventory:2,657

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Product details

Overview

AP1121ASL-13 from Diodes Incorporated is a dual-channel, low-dropout positive voltage regulator delivering 1A per channel with fixed outputs of 3.3V (CH1) and 2.5V (CH2), maximum 1.3V dropout at full load, fast transient response, and independent thermal shutdown and current limiting per channel. It targets dual-rail logic supply in PC peripherals and communication equipment operating from up to 18V input.

For engineers reviewing the AP1121ASL-13 datasheet, AP1121ASL-13 pinout, AP1121ASL-13 application, or AP1121ASL-13 equivalent, key selection criteria include dual-output stability under dynamic load, dropout performance at 1A, thermal behavior in SOP-8L, and compatibility with 10µF/0.15–20Ω ESR output capacitors.

Technical Context

The AP1121ASL-13 integrates two independent LDO regulators sharing ground terminals but featuring separate input and output pins, each with dedicated current-limit and thermal-shutdown circuitry. Its internal architecture uses PNP pass transistors with 1.25V reference-based error amplifiers for regulation.

It operates across 0°C to +125°C junction temperature, supports input voltages up to 18V, and maintains ≤25mV load regulation on CH2 (2.5V) and ≤33mV on CH1 (3.3V) across 0–1A load range - critical for noise-sensitive digital ICs requiring stable dual-rail biasing.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage CH1	3.300 V ±1.9% (3.235–3.365 V); ensures TTL/CMOS-compatible 3.3V rail compliance at 10mA–1A loads
Output Voltage CH2	2.500 V ±2.0% (2.450–2.550 V); supplies standard 2.5V logic families without external feedback
Dropout Voltage	1.3 V max at 1A; enables regulation from 4.8V input on CH1 and 4.0V on CH2, extending usable input range
Load Regulation	≤33 mV (CH1), ≤25 mV (CH2); minimizes output sag during CPU/GPU burst currents in peripheral designs
Ripple Rejection	60–70 dB at 120 Hz; suppresses switching noise from upstream DC/DC converters feeding the LDO inputs
Thermal Resistance θ_JA	158 °C/W (dual-channel operation); requires PCB copper area ≥5.5 mm × 5.5 mm per output for safe 1A continuous operation

Pinout & Package

SOP-8L package (4.9 mm × 3.9 mm × 1.75 mm max height), lead-free and RoHS-compliant, with exposed thermal pad not connected internally - requires external copper pour for thermal management.

Pin/Terminal	Circuit Role	Design Meaning
1 - VOUT1	CH1 regulated output	3.3V rail; requires ≥10 µF capacitor (0.15–20 Ω ESR) to ground for stability
2 - VOUT2	CH2 regulated output	2.5V rail; same capacitor requirement as VOUT1; independent regulation loop
3 - VIN1	CH1 input supply	Accepts 4.8–18V; decoupling capacitor recommended between VIN1 and GND
4 - VIN2	CH2 input supply	Accepts 4.0–18V; electrically isolated from VIN1 for mixed-input systems
5–8 - GND	Common ground terminals	All four GND pins must be tied to low-impedance ground plane; shared return for both channels

Key Features

Feature	Design Value
Dual independent LDOs	Two fully isolated regulation paths with separate VIN/VOUT/GND connections - enables split-rail or differential input configurations
Fast transient response	Sub-10 µs recovery from 100 mA ↔ 1 A load steps - maintains logic rail integrity during processor wake/sleep transitions
Per-channel protection	Independent current limit (~1.1 A) and thermal shutdown per channel - prevents single-fault cascade failure
Low-noise operation	60–70 dB ripple rejection + <0.5% temperature drift - suitable for ADC reference or PLL supply rails

Applications

PC Peripheral Power

Communication Interface Supply

Use Scenario: Powering USB 3.0 hub controller, SATA bridge IC, and PCIe switch in desktop add-in cards.

IC Role / Device Role / Timing Role: Dual-rail LDO supplying 3.3V I/O and 2.5V core logic simultaneously from a shared 5V or 12V source.

Use Value: Eliminates need for two discrete regulators, reducing BOM count and PCB area while maintaining tight load regulation (<33 mV) across both rails.

Use Scenario: Providing clean 3.3V and 2.5V supplies to RS-485 transceivers, Ethernet PHYs, and optical module drivers.

IC Role / Device Role / Timing Role: Low-noise local regulation stage downstream of noisy DC/DC converters in industrial comms modules.

Use Value: 70 dB ripple rejection attenuates switching artifacts that could corrupt differential signaling integrity or increase bit error rate.

Embedded Controller Bias

FPGA I/O Bank Regulation

Use Scenario: Biasing ARM Cortex-M7 microcontroller with 3.3V I/O and 2.5V analog subsystem (ADC, DAC, op-amps).

IC Role / Device Role / Timing Role: Primary linear regulator delivering precision analog and digital domain supplies from a single input rail.

Use Value: <0.5% temperature stability and <25 mV load regulation ensure ADC reference accuracy remains within ±1 LSB over full operating temperature range.

Use Scenario: Powering multiple FPGA I/O banks requiring 3.3V and 2.5V simultaneously on compact carrier boards.

IC Role / Device Role / Timing Role: Compact dual-output LDO replacing discrete solutions to meet tight board space constraints in modular FPGA systems.

Use Value: SOP-8L footprint with integrated dual regulation reduces layout complexity and improves power delivery symmetry across adjacent I/O banks.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output LDO regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TPS7A4700RGWR	Single-channel, ultra-low-noise (4.7 µV_RMS), adjustable output; no dual fixed-voltage option	Requires external resistors for 3.3V/2.5V; lacks per-channel current limit and thermal shutdown	Preferred only when sub-10 µV noise is mandatory and dual outputs can be implemented discretely
RT9013-33PB	Single 3.3V LDO (300 mA), no 2.5V channel; different package (SOT-23-5)	Cannot replace dual-output function without adding second regulator and associated passives	Only viable for CH1-only replacement where CH2 is removed or sourced elsewhere

Compared with TPS7A4700RGWR and RT9013-33PB, AP1121ASL-13 uniquely delivers matched, protected dual outputs in one SOP-8L package - eliminating design overhead for coordination, sequencing, and layout symmetry required by discrete dual-LDO implementations.

Availability

AP1121ASL-13 is available at Aetrix Electronics and suitable for PC peripheral power, communication interface supply, and embedded controller bias applications requiring stable component supply and long-term production continuity.

Supply support for AP1121ASL-13 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-reliability power management, signal integrity, and protection solutions for industrial, computing, and communications markets.

The AP1121 series belongs to Diodes' precision dual-LDO product line, engineered specifically for space-constrained, multi-rail digital systems needing simultaneous 3.3V/2.5V or 3.3V/1.8V regulation with robust fault protection.

FAQ

What is the minimum output capacitor value required for stability on AP1121ASL-13?

A minimum 10 µF tantalum or ceramic capacitor with ESR between 0.15 Ω and 20 Ω is required on each output (VOUT1 and VOUT2) to ensure loop stability across all load and temperature conditions. Lower ESR values may cause oscillation; higher ESR degrades transient response and increases output ripple.

Can AP1121ASL-13 operate with an input voltage lower than 4.8V on CH1?

No - CH1 requires VIN1 ≥ 4.8V to guarantee 3.3V regulation at full 1A load due to its 1.3V dropout specification. At 4.5V input, output drops below 3.2V under full load, violating datasheet limits. Operation below 4.8V is only permissible at reduced load currents, calculated via VOUT = VIN − V_DO(IOUT).

How are the four GND pins used in the SOP-8L package?

All four GND pins (pins 5–8) are internally connected to the same substrate ground node and must be soldered to a common low-impedance PCB ground plane. They serve to reduce thermal resistance and improve current-handling capability - splitting them across separate ground nets compromises thermal performance and may trigger premature thermal shutdown.

Is AP1121ASL-13 still in active production?

AP1121ASL-13 is marked obsolete in Diodes' official documentation (DS31011 Rev. 6-4, October 2021), but Aetrix Electronics maintains legacy inventory and offers controlled-life-cycle support including last-time-buy planning, cross-reference assistance, and engineering consultation for migration paths to active alternatives.

AP1121ASL-13 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Discontinued at Digi-Key

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 2

Voltage - Input (Max):: 18V

Voltage - Output (Min/Fixed):: 2.5V, 3.3V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 1.4V @ 1A, 1.4V @ 1A

Current - Output:: 1A, 1A

Current - Quiescent (Iq):: 10 mA

Current - Supply (Max):: -

PSRR:: 60dB (120Hz)

Control Features:: -

Protection Features:: Over Current, Over Temperature

Operating Temperature:: 0°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOP

AP1121ASL-13 FAQ

1.How can I place an order for AP1121ASL-13 through Aetrix?

Please submit a Request for Quotation (RFQ) for AP1121ASL-13 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 AP1121ASL-13 reliable?

The price and inventory of AP1121ASL-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP1121ASL-13 is usually 5 days.

3.What payment methods are accepted for AP1121ASL-13?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP1121ASL-13 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AP1121ASL-13?

AP1121ASL-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AP1121ASL-13 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 AP1121ASL-13?

For technical support, including AP1121ASL-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP1121ASL-13 requirements.

6.How does Aetrix verify that AP1121ASL-13 is sourced from the original manufacturer or authorized distributors?

All AP1121ASL-13 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 AP1121ASL-13 meets industry standards.

7.What is the process for return or replacement of AP1121ASL-13?

All AP1121ASL-13 units undergo pre-shipment inspection (PSI). If there is an issue with AP1121ASL-13, 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 AP1121ASL-13 part is unused and in its original packaging.

Return procedure for AP1121ASL-13:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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