onsemi CMPWR330SF

Overview

CMPWR330SF from onsemi is a dual-input 3.3 V SmartOR regulator with integrated VAUX switch, delivering up to 400 mA continuously. It selects power from VCC (5 V), VSBY (5 V), or VAUX (3.3 V) in strict priority order and provides low-impedance VAUX-to-VOUT pass-through (0.25 Ω typ.) when only VAUX is active. Used in PCI adapter cards with Wake-on-LAN for seamless standby-to-active transitions.

For engineers reviewing the CMPWR330SF datasheet, pinout, applications, or equivalent options, key selection criteria include input supply prioritization logic, 0.25 Ω VAUX switch R_DS(ON), foldback current limiting, thermal shutdown at 160°C, and compatibility with 8-pin Power SOIC layout constraints.

Technical Context

The CMPWR330SF implements automatic input source selection using comparator-based control with 4.4 V VCC select threshold and 4.2 V deselect threshold, yielding 0.2 V hysteresis to prevent chatter. Its internal regulator delivers regulated 3.3 V ±5% over 0–400 mA load, while the VAUX path operates as a low-R_DS(ON) MOSFET switch-not a linear regulator-enabling direct 3.3 V pass-through.

Power sequencing is fully autonomous: VCC takes precedence; if VCC drops below 4.2 V and VSBY is present, VSBY powers the regulator; if both VCC and VSBY are absent, VAUX connects directly to VOUT. All transitions maintain uninterrupted VOUT via internal charge management and 10 µF output capacitance requirement.

Key Specifications

Pinout & Package

CMPPWR330SF is housed in an 8-pin Power SOIC package (Case 751BD), thermally enhanced with pins 5–8 tied to the exposed leadframe for GND and heat dissipation. The package complies with JEDEC MS-012 and features RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-input power management applications.

Compared with TPS2113AIDGQR and RT9711CGQW, the CMPWR330SF uniquely integrates both 400 mA 3.3 V regulation and true three-tier priority (VCC→VSBY→VAUX) with low-R_DS(ON) VAUX pass-through-enabling single-component solutions for systems requiring auxiliary 3.3 V sourcing without external regulators or switches.

Availability

CMPWR330SF is available at Aetrix Electronics and suitable for PCI adapter cards with Wake-on-LAN, network interface cards (NICs), and systems with standby capabilities requiring stable component supply across automotive-grade temperature ranges and long-lifecycle production programs.

Supply support for CMPWR330SF 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient innovation for automotive, industrial, cloud, and intelligent edge applications.

The CMPWR330SF belongs to onsemi's SmartOR™ family of power-path controllers, designed specifically for seamless multi-rail power management in systems requiring reliable wake-from-standby operation without software intervention.

FAQ

What is the exact function of the VAUX pin on the CMPWR330SF?

The VAUX pin on the CMPWR330SF serves as the third-priority 3.3 V input source. When both VCC and VSBY are absent or below their respective thresholds, the CMPWR330SF enables an internal low-R_DS(ON) switch (0.25 Ω typical) to connect VAUX directly to VOUT. This pass-through mode avoids regulation losses and preserves VAUX rail accuracy, making it ideal for battery-backed or auxiliary 3.3 V domains. The CMPWR330SF does not regulate VAUX-it routes it.

Does the CMPWR330SF require external components for stable operation?

Yes-the CMPWR330SF requires a 10 µF ceramic capacitor at VOUT for loop stability and transient suppression during input source transitions. Bypass capacitors (1–10 µF) are recommended at VCC and VSBY if traces exceed a few inches from the main input filter. No external compensation or feedback resistors are needed, as regulation and switching logic are fully integrated. The CMPWR330SF operates autonomously with these minimal external parts.

How does the CMPWR330SF handle simultaneous presence of VCC and VSBY?

The CMPWR330SF gives absolute priority to VCC over VSBY. If VCC exceeds 4.4 V, it powers the regulator regardless of VSBY status. VSBY only becomes active when VCC falls below 4.2 V. The 0.2 V hysteresis between select (4.4 V) and deselect (4.2 V) thresholds prevents oscillation during marginal VCC conditions. VSBY never powers the device while VCC is valid-even if VSBY voltage is higher-ensuring deterministic behavior. This logic is hardwired and requires no configuration.

What thermal design considerations apply to the CMPWR330SF?

The CMPWR330SF uses an 8-pin Power SOIC package with pins 5–8 internally connected to the leadframe as GND and thermal paths. To achieve the specified 50°C/W junction-to-ambient thermal resistance, at least 2 in² of copper area must be connected to these GND pins on a double-sided PCB. Without this, θ_JA rises to 70°C/W, limiting safe power dissipation. The CMPWR330SF includes thermal shutdown at 160°C with 20°C hysteresis, but proper board-level heatsinking is required for continuous 400 mA operation at 70°C ambient.

Can the CMPWR330SF be used in automotive applications?

The CMPWR330SF is specified for 0°C to +70°C ambient operation and is not qualified to AEC-Q100 standards. While its electrical characteristics (e.g., 6 V absolute max input, ±2 kV HBM ESD) provide margin beyond typical automotive requirements, onsemi does not certify or recommend the CMPWR330SF for automotive use. For automotive infotainment or body control modules requiring multi-rail power management, onsemi offers AEC-Q100-qualified alternatives such as the NCV8853. The CMPWR330SF targets industrial, computing, and networking applications.