Diodes Incorporated AP7340-33FS4-7

Overview

AP7340-33FS4-7 from Diodes Incorporated is a fixed-output 3.3V, 150mA low-dropout linear regulator with ±1% output voltage accuracy, 75dB PSRR at 1kHz, and 60µV_rms output noise (10Hz–100kHz). Built on a CMOS process, it features enable control, low 35µA quiescent current, and operates from 1.7V to 5.25V input - optimized for RF supply rails in portable wireless communication devices.

For engineers reviewing the AP7340-33FS4-7 datasheet, AP7340-33FS4-7 pinout, AP7340-33FS4-7 application, or AP7340-33FS4-7 equivalent, key selection criteria include dropout voltage at 150mA (0.21–0.27V), thermal performance in X2-DFN1010-4, EN logic thresholds (0.5V_IL/1.3V_IH), and stability with 0.47µF ceramic capacitors.

Technical Context

The AP7340-33FS4-7 integrates a precision voltage reference, error amplifier, current-limit circuit, and CMOS pass transistor - enabling fast line/load transient response and high PSRR without external compensation. Its non-discharge architecture avoids automatic VOUT discharge during shutdown.

Operation requires only two 0.47µF ceramic capacitors (CIN/COUT), with layout-critical thermal pad connection to GND for thermal dissipation. Enable functionality supports controlled power sequencing, with EN pin leakage <±1.0µA and defined turn-on/off thresholds.

Key Specifications

Pinout & Package

The AP7340-33FS4-7 is housed in a 1.0mm × 1.0mm X2-DFN1010-4 package with exposed thermal pad, supporting ultra-dense PCB layouts in space-constrained handheld devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-3302E/TO and XC6206P332MR-G, the AP7340-33FS4-7 uniquely balances 75dB PSRR, 35µA IQ, and enable control in a 1.0mm² DFN - making it optimal for space-constrained, noise-sensitive RF and imaging subsystems.

Availability

AP7340-33FS4-7 is available at Aetrix Electronics and suitable for smartphone baseband power, RF transceiver bias supply, and portable camera sensor rail applications requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for AP7340-33FS4-7 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-reliability power management, signal integrity, and protection solutions for consumer, industrial, and communications markets.

The AP7340 belongs to Diodes' high-PSRR, low-noise LDO family designed specifically for noise-sensitive analog and RF power domains in portable wireless equipment - emphasizing small footprint, low IQ, and robust transient response.

FAQ

What is the minimum input voltage required for AP7340-33FS4-7 to maintain regulation at full 150mA load?

The minimum input voltage is determined by dropout voltage plus nominal output: 3.3V + 0.27V (max dropout at 150mA) = 3.57V. At ambient temperatures up to +85°C, the device sustains regulation down to 3.57V input. Below this, output voltage drops proportionally - verified per Electrical Characteristics Table, Note 5.

Can AP7340-33FS4-7 be used without an enable signal, and how should the EN pin be handled?

Yes - tie EN directly to VIN to maintain continuous operation. The EN pin must never float; its logic thresholds are 0.5V (max low) and 1.3V (min high). With VIN ≥1.7V, direct connection ensures reliable enablement. Do not connect EN to partial-voltage dividers - insufficient drive strength risks undefined state.

Is the thermal pad on the X2-DFN1010-4 package electrically connected, and how should it be routed?

The thermal pad is internally connected to GND and must be soldered to a PCB copper pour tied to the system ground plane. Per datasheet Figure 1 and Package Outline, this improves thermal resistance by ~30°C/W and prevents overheating at 150mA. Do not leave it unconnected or use it solely as a mechanical anchor - thermal performance degrades significantly without GND connection.

Does AP7340-33FS4-7 include short-circuit protection, and what is the trip threshold?

Yes - fold-back short-circuit protection activates when VOUT is pulled to GND, limiting output current to approximately 55–60mA (per Electrical Characteristics table, "Fold-back Short Current"). This protects the IC from thermal damage during sustained faults and is independent of EN state - active even in shutdown mode if VIN remains applied.