onsemi CAT661EVA

Overview

CAT661EVA from onsemi is a high-frequency CMOS charge-pump voltage converter capable of inverting +2.5 V to +5.5 V inputs to negative outputs or doubling inputs to 5 V–11 V positive outputs, with guaranteed 100 mA output current, 10 Ω max output resistance, and selectable 25 kHz or 135 kHz oscillator frequency - used in GaAs FET biasing, LCD contrast generation, and lithium battery-powered instrumentation.

For engineers reviewing the CAT661EVA datasheet, pinout, applications, or equivalent options, this device supports low-EMI power conversion without inductors, offers precise voltage splitting for symmetrical rail generation, and enables cascaded/parallel configurations for extended voltage range or reduced output impedance.

Technical Context

The CAT661EVA implements a switched-capacitor topology with dual-mode operation: in inverter mode (LV = GND), it generates −V_IN at OUT using CAP+ and CAP−; in doubler mode (LV = OUT), it produces 2×V_IN with V+ as output and GND as reference. Its internal oscillator supports four frequency control methods: BOOST/FC open (25 kHz), BOOST/FC tied to V+ (135 kHz), external capacitor at OSC, or external clock drive.

Output impedance is determined by internal switch resistance plus 4×C1 ESR + C2 ESR; efficiency reaches 98% at 1 kΩ load in doubler mode and 96% at 500 Ω in inverter mode. The device operates across −40°C to +85°C ambient and tolerates input voltages up to 6 V absolute maximum.

Key Specifications

Pinout & Package

Package: SOIC-8, 150-mil body, RoHS-compliant, Pb-free, halogen-free/BFR-free.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar charge-pump voltage converter applications.

Compared with MAX660CPA+ and LTC1044CS8#PBF, the CAT661EVA provides 2.5× higher output current, selectable high-frequency operation for miniaturized capacitors, and integrated LV pin for seamless mode switching - making it the only option supporting 100 mA loads in SOIC-8 without inductors.

Availability

CAT661EVA is available at Aetrix Electronics and suitable for GaAs FET biasing, LCD contrast generation, and portable instrumentation requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for CAT661EVA 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 specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, and portable applications.

The CAT661EVA belongs to onsemi's high-efficiency charge-pump converter product line, designed specifically to eliminate inductors in low-to-moderate power portable systems while maintaining precision voltage generation and low EMI.

FAQ

What is the maximum input voltage rating for the CAT661EVA?

The CAT661EVA has an absolute maximum V+ to GND rating of 6 V. Operation above 5.5 V violates recommended conditions and risks permanent damage. For reliable long-term performance, input voltage must remain within 2.5 V to 5.5 V across the full temperature range, as specified in Table 3 of the CAT661/D datasheet. Exceeding 6 V even momentarily may degrade internal switches or oxide layers in the CAT661EVA.

Can the CAT661EVA be used to generate both positive and negative outputs simultaneously from one device?

No, the CAT661EVA operates in either inverter mode (producing −V_IN) or doubler mode (producing 2×V_IN) - not both simultaneously. To achieve dual-rail outputs like ±V_IN, two CAT661EVA devices must be used: one in inverter mode for the negative rail and another in doubler mode with appropriate level-shifting, or a single CAT661EVA in battery-splitter configuration (Figure 27) which yields symmetrical ±V_BAT/2. The CAT661EVA itself does not integrate dual-output circuitry.

What capacitor types and values are recommended for stable CAT661EVA operation at 100 mA load?

For 100 mA operation, use low-ESR tantalum or polymer aluminum electrolytic capacitors: C1 = 100 μF (ESR ≤ 0.2 Ω) at CAP+ and CAP−, and C2 = 150 μF (ESR ≤ 0.2 Ω) at OUT. Ceramic capacitors are unsuitable due to insufficient capacitance and microphonic effects. AVX TPS series or Sanyo MV-AX series are validated suppliers per Table 6 in the CAT661/D datasheet. Using higher-ESR capacitors increases output resistance and ripple beyond specification in the CAT661EVA.

Is the CAT661EVA pin-compatible with the ICL7660S?

Yes, the CAT661EVA is pin-compatible with the ICL7660S and industry-standard 7660/1044 family in SOIC-8 package (Case 751BD), sharing identical pin numbering and basic function mapping. However, the CAT661EVA adds BOOST/FC and LV pins with enhanced functionality - LV must be tied to OUT in doubler mode, unlike the 7660S. No PCB redesign is needed for drop-in replacement, but firmware or external biasing may require review to leverage CAT661EVA's higher current and frequency capabilities.

How does the LV pin affect CAT661EVA operation below 3 V input?

When input voltage is below 3 V, the LV pin must be connected to GND to enable proper low-voltage switching thresholds inside the CAT661EVA - failure to do so causes erratic oscillation or failure to start. At inputs ≥3 V, LV may be left open or tied to GND with no functional impact. In doubler mode, LV is always tied to OUT regardless of input voltage, as required by the internal charge-transfer architecture of the CAT661EVA.