Analog Devices Inc./Maxim Integrated MAX680CSA+T

Overview

The MAX680CSA+T from Maxim Integrated is a monolithic CMOS dual charge-pump voltage converter that generates ±10V outputs from a single +5V input supply. It requires four external capacitors, delivers up to 10mA output current per rail, exhibits 150Ω typical positive output source resistance and 90Ω negative output source resistance at +25°C, and operates with an internal 8kHz oscillator - commonly used in op-amp power supplies and data-acquisition systems requiring bipolar rails from a single logic supply.

For engineers reviewing the MAX680CSA+T datasheet, MAX680CSA+T pinout, MAX680CSA+T application, or MAX680CSA+T equivalent, key selection criteria include input voltage range (+2V to +6V), output source impedance temperature dependence, ±10V load droop behavior under asymmetric loading, and SO-8 package compatibility with space-constrained analog front-ends.

Technical Context

The MAX680CSA+T implements two independent switched-capacitor charge pumps: a positive doubler (VCC → V+) and an inverting pump (V+ → V−), with non-overlapping 8kHz clock phases driving eight CMOS power MOSFET switches (four P-channel, four N-channel). The positive pump charges C1 during phase one and transfers charge to C3; the negative pump uses V+ as its input source to charge C2 and transfer to C4.

It is not a regulated device: output voltages droop linearly with load current per rail (VDROP+ = (IL+ + IL−) × RS+, VDROP− = IL− × RS−), and ripple is governed by VRIPPLE = ½ × IOUT × (1/8kHz) × (1/CR), where CR is the reservoir capacitor value - requiring careful capacitor selection for <30mVpp ripple at 5mA.

Key Specifications

Pinout & Package

MAX680CSA+T is housed in an 8-pin narrow SO (SOIC-8) package, 3.9mm × 4.9mm body, 1.27mm pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX680CSA+T, MAX681CPD removes external component dependency at the cost of larger package and fixed capacitance, while MAX864ESA+ improves dynamic performance and miniaturization but shifts design toward higher-frequency layout practices.

Availability

MAX680CSA+T is available at Aetrix Electronics and suitable for operational amplifier power supplies, data-acquisition systems, and panel meters requiring stable component supply with long-term industrial availability.

Supply support for MAX680CSA+T 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

Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX680 product line delivers compact, capacitor-based dual-rail voltage conversion for space- and power-constrained analog systems - designed specifically for replacing bulky inductor-based solutions in portable and embedded instrumentation.

FAQ

What is the maximum continuous output current supported by the MAX680CSA+T?

The MAX680CSA+T supports up to 10mA per output rail (V+ and V−) under typical conditions (VCC = 5V, TA = +25°C). At this load, V+ droops ~1.5V (due to 150Ω source resistance) and V− droops ~0.9V (due to 90Ω source resistance), resulting in ~+8.5V and ~−9.1V output. Derating is required at elevated temperatures or lower input voltages.

Can the MAX680CSA+T generate ±10V from a 3V input?

No - the MAX680CSA+T requires a minimum +2V input but cannot reliably produce ±10V from 3V. Its architecture doubles VCC for V+ and inverts V+ for V−, so 3V input yields only ~+6V and ~−6V. For ±6V from 3V, the MAX680CSA+T is explicitly validated and commonly used in handheld instruments and battery-powered meters.

What capacitor values are recommended for stable operation of the MAX680CSA+T?

For stable ±10V operation from +5V, use four 10µF polarized electrolytic capacitors rated ≥6V (C1, C3) and ≥12V (C2, C4). At 5mA load, this yields <30mVpp ripple. For low-current applications (<1mA), 1µF (C1, C2) and 4.7µF (C3, C4) suffice. All capacitors must have low ESR (<1Ω) to maintain efficiency and minimize droop.

Is the MAX680CSA+T pin-compatible with the MAX681 series?

No - the MAX680CSA+T uses an 8-pin SO package with four external capacitor terminals (C1+, C1−, C2+, C2−), while the MAX681CPD uses a 14-pin DIP with no external capacitor pins. Their pinouts, package footprints, and capacitor interface architectures are fundamentally incompatible; PCB redesign is required for substitution.

Does the MAX680CSA+T include overcurrent or thermal protection?

No - the MAX680CSA+T has no internal overcurrent, short-circuit, or thermal shutdown circuitry. Its absolute maximum ratings specify continuous V− short-circuit tolerance, but sustained overload causes unregulated droop and potential overheating. External current limiting (e.g., series resistors or dedicated supervisors like MAX663) is required for robust system-level protection.