Diodes Incorporated AP1661AP-G1

Overview

AP1661AP-G1 from BCD Semiconductor is a high-performance active power factor correction (PFC) controller IC designed for pre-converter stages in AC-DC adapters, off-line SMPS, and electronic ballasts. It implements zero-current detection for DCM boundary conduction mode, features a totem-pole gate driver (600 mA source / 800 mA sink), and meets IEC61000-3-2 with THD <10% at full load and high-line voltage.

For engineers reviewing the AP1661AP-G1 datasheet, AP1661AP-G1 pinout, AP1661AP-G1 application, or AP1661AP-G1 equivalent, key selection criteria include its 2.5 mA typical quiescent current, 2.5 V UVLO hysteresis, precision 2.5 V internal reference (±1%), adjustable OVP threshold, and DIP-8 package compatibility with legacy through-hole board layouts.

Technical Context

The AP1661AP-G1 employs a one-quadrant analog multiplier with 0.45–0.75 V⁻¹ gain and linear input range up to 3.5 V, enabling precise current shaping for near-unity PF. Its zero-current detector (ZCD) input triggers at 2.1 V with 0.5 V hysteresis and disables operation when pulled below 200 mV.

Control architecture integrates an error amplifier with 80 dB open-loop gain and 1 MHz GBW, internal 7 V zener clamp on VCC, and a dedicated restart timer (70–400 µs) activated after over-voltage or under-voltage events. The totem-pole output drives external MOSFETs directly without external buffers.

Key Specifications

Pinout & Package

DIP-8 package with 0.3 inch body width, 2.54 mm lead pitch, and RoHS-compliant green finish (G1 suffix). Designed for through-hole mounting and thermal dissipation up to 1 W at TA = 50 °C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PFC controller applications.

Compared with UCC28019DR and FAN7527B, the AP1661AP-G1 offers superior integration (internal ZCD, disable pin, startup timer), lower quiescent current, and tighter reference tolerance-making it optimal for compact, low-to-mid-power DCM PFC stages where component count and standby loss matter.

Availability

AP1661AP-G1 is available at Aetrix Electronics and suitable for AC-DC adapters, off-line SMPS, and electronic ballast designs requiring stable component supply, RoHS-compliant packaging, and long-term industrial availability.

Supply support for AP1661AP-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 analog and mixed-signal IC designer and foundry partner specializing in high-voltage, high-efficiency power management solutions.

The AP1661A product line targets cost-effective, discrete-component-compatible PFC controllers for universal-input offline power conversion, emphasizing integration, low-loss operation, and compliance with global harmonic standards.

FAQ

What is the function of Pin 5 (ZCD) on the AP1661AP-G1?

Pin 5 (ZCD) is the zero-current detection input that monitors inductor current zero-crossing to enable boundary-mode DCM operation. When pulled below 200 mV, it disables the gate driver and reduces supply current to 20–90 µA. Its 2.1 V trigger threshold and 0.5 V hysteresis ensure noise-immune timing for accurate conduction cycle termination.

Does the AP1661AP-G1 require an external startup resistor?

Yes-the AP1661AP-G1 requires an external high-voltage startup resistor connected between the AC rectified input and VCC (Pin 8) to charge the VCC capacitor until UVLO turn-on at 12.5 V. The 30 µA typical start-up current minimizes power loss in this network, and the internal 7 V zener clamps VCC during normal operation.

How is over-voltage protection implemented on the AP1661AP-G1?

OVP is implemented via the INV pin (Pin 1): when the feedback voltage exceeds 2.25 V (±0.15 V), the internal comparator triggers a shutdown sequence. This threshold is set by the internal 2.5 V reference and resistor divider ratio, allowing precise, adjustable protection of the DC bus without additional components.

Can the AP1661AP-G1 be used in continuous conduction mode (CCM)?

No-the AP1661AP-G1 is specifically designed for discontinuous conduction mode (DCM) boundary operation using zero-current detection. Its functional block diagram, pin configuration (dedicated ZCD input), and datasheet specifications confirm DCM-only operation; CCM requires different control architecture and is not supported.