Diodes Incorporated AP1121BSG-13

Overview

AP1121BSG-13 from Diodes Incorporated is a dual-channel low-dropout linear regulator delivering 1A per channel with fixed outputs of 3.3V (CH1) and 1.8V (CH2), 1.3V max 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 interfaces operating from up to 18V input.

For engineers reviewing the AP1121BSG-13 datasheet, AP1121BSG-13 pinout, AP1121BSG-13 application, or AP1121BSG-13 equivalent, key selection criteria include verified dual-output voltage pairing, SOP-8L thermal resistance (158°C/W junction-to-ambient under dual-load), dropout compliance at 1A, ripple rejection (60–70dB at 120Hz), and RoHS-compliant green packaging.

Technical Context

The AP1121BSG-13 integrates two independent LDO regulators sharing a common ground plane but featuring separate VIN and GND terminals per channel - enabling decoupled input filtering and reduced crosstalk. Each channel employs a PNP pass transistor with internal 1.25V reference and current-sense circuitry for overcurrent protection.

Thermal shutdown activates independently per channel when junction temperature exceeds 150°C, and load regulation remains within ±25mV across 0–1A for CH2 (1.8V) and ±33mV for CH1 (3.3V). The device requires minimum 10µF output capacitance (ESR 0.15–20Ω) per channel for stability.

Key Specifications

Pinout & Package

SOP-8L package (4.9mm × 6.0mm × 1.75mm), lead-free, green molding compound, 1.27mm pitch, exposed thermal pad not present - thermal management relies on PCB copper area per channel.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A1633ADBVR and RT9013-33PB, AP1121BSG-13 uniquely delivers dual 1A outputs with per-channel protection in a single SOP-8L package - reducing component count, PCB area, and failure modes in space-constrained dual-rail systems.

Availability

AP1121BSG-13 is available at Aetrix Electronics and suitable for PC peripheral power delivery, industrial Ethernet PHY supply, and embedded camera module design requiring stable component supply and long-term obsolescence mitigation support.

Supply support for AP1121BSG-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 semiconductor company specializing in discrete, analog, and mixed-signal solutions, with design centers across Asia, Europe, and the US, serving industrial, computing, and communications markets.

The AP1121 series belongs to Diodes' precision dual-LDO product line, engineered specifically for high-speed bus termination and low-voltage logic supply in space-constrained applications where dual-rail independence and robust thermal behavior are essential.

FAQ

What are the exact output voltage tolerances for AP1121BSG-13?

The AP1121BSG-13 specifies CH1 (3.3V) output as 3.235–3.365V and CH2 (1.8V) as 1.764–1.836V at 10mA load and 25°C ambient, corresponding to ±2% tolerance for both channels per datasheet DS31011 Rev. 6–4.

Can AP1121BSG-13 operate with a 15V input supply?

Yes - the absolute maximum VIN rating is 18V, and the device guarantees ≤1.3V dropout at full 1A load. At 15V input, CH1 delivers 3.3V with 11.7V differential drop, dissipating up to 11.7W per channel under worst-case conditions, requiring appropriate PCB copper area per thermal guidelines.

Is external compensation required for stability?

No - the AP1121BSG-13 is internally compensated and stable with ≥10µF output capacitance per channel using capacitors with ESR between 0.15Ω and 20Ω, as verified in the typical application circuit and stability test data on page 4 of DS31011.

Does AP1121BSG-13 support power sequencing between its two outputs?

No - both channels power up simultaneously with no built-in sequencing control; however, external RC delay networks on VIN1/VIN2 can be used to stagger turn-on, and the independent enable functionality is not present - sequencing must be implemented externally if required.