Diodes Incorporated AP8800EV1

Overview

AP8800 from Diodes Incorporated is a 350mA constant-current step-down DC/DC LED driver IC operating from 8V to 28V input, supporting up to seven series-connected LEDs with 92% peak efficiency, 600kHz max switching frequency, and dual-mode (PWM/analog) dimming via the CTRL pin. It is used in commercial lighting and LCD backlighting where uniform current distribution and compact layout are critical.

For engineers reviewing the AP8800 datasheet, AP8800 pinout, AP8800 application, or AP8800 equivalent, key selection criteria include its hysteretic control architecture, external R_SET-programmed output current, open-circuit LED protection, SO-8/MSOP-8/U-DFN3030-10 package options, and thermal derating behavior across ambient temperatures.

Technical Context

The AP8800 employs a hysteretic (constant-on-time) control topology that regulates LED current by sensing voltage across an external R_SET resistor and comparing it to an internal 100mV threshold. Its switching cycle self-adjusts based on input voltage and LED string voltage, maintaining stable average current without requiring compensation networks.

It integrates a 1.7Ω typical R_DS(ON) internal N-channel MOSFET switch, supports analog dimming via 0.3–2.5V CTRL input (24–200% I_LED), and accepts PWM signals for precise low-current dimming. The device enters ultra-low-quiescent standby (<30μA) when CTRL ≤ 0.2V.

Key Specifications

Pinout & Package

AP8800 is available in three RoHS-compliant, lead-free packages: SO-8 (92°C/W θ_JA), MSOP-8 (120°C/W), and U-DFN3030-10 (46°C/W). Thermal performance varies significantly-U-DFN3030-10 offers best power dissipation for high-current designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED driver applications.

Compared with AP8800, AL8860 offers higher current but sacrifices analog dimming, while AL8861 adds topology flexibility at the cost of increased design complexity-AP8800 remains optimal for cost-sensitive, fixed-input, medium-current LED lighting with dual dimming modes.

Availability

AP8800 is available at Aetrix Electronics and suitable for commercial lighting, LCD backlighting, architectural detail lighting, and appliance interior lighting requiring stable component supply, RoHS compliance, and long-term manufacturability.

Supply support for AP8800 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 ICs, specializing in high-efficiency power management, signal integrity, and lighting solutions for industrial, consumer, and automotive markets.

The AP8800 belongs to Diodes' LED driver product line, designed specifically for cost-effective, thermally robust constant-current regulation in medium-power DC-powered lighting systems with stringent size and efficiency requirements.

FAQ

What is the minimum input voltage required for AP8800 to regulate 350mA into a 7-LED string?

The AP8800 requires sufficient headroom between VIN and total LED forward voltage (V_F). For a 7×3.2V (22.4V) string, minimum VIN is ~23.5V to maintain regulation-well within its 8–28V range. At lower VIN, output current drops due to reduced duty cycle; datasheet Figure 3 confirms stable operation down to 8V only for shorter LED strings (e.g., 1–2 LEDs).

How does the AP8800 handle shorted LED faults?

When one or more LEDs short, the AP8800 continues switching but exhibits altered dynamics: ramp-up time shortens (higher dI/dt), ramp-down time lengthens, and switching frequency shifts downward. Unlike open-circuit faults, no automatic shutdown occurs-designers must rely on system-level monitoring or thermal limits to detect abnormal operation.

Can the RSVD pin be left floating?

No-the RSVD pin must be connected directly to GND with the shortest possible trace. Leaving it floating risks instability, erratic switching, or failure to start. This requirement is explicitly stated in the datasheet Pin Descriptions section and verified in application note DS31764 Rev. 8–3, page 5.

What is the recommended capacitor type and value for the CTRL pin soft-start function?

A ceramic capacitor (X5R or X7R) from CTRL to GND is recommended. Soft-start time is 0.5ms per nanofarad (e.g., 2.2nF yields ~1.1ms delay). This capacitor slows the rise of CTRL voltage during startup, limiting inrush current and preventing overshoot in LED current-critical for reliability in high-volume lighting assemblies.