Microchip Technology TC682COA

Overview

TC682COA from Microchip Technology is a CMOS charge pump voltage inverter that generates a regulated negative doubled output (VOUT = –2 × VIN) from a single positive input supply. It operates over 2.4V to 5.5V input, delivers up to 10 mA output current with 140 Ω typical source resistance, and achieves 99.9% voltage conversion efficiency and 92% power efficiency. It is used in portable instruments and LCD bias generation where compact dual-rail analog supplies are required.

For engineers reviewing the TC682COA datasheet, TC682COA pinout, TC682COA application, or TC682COA equivalent, key selection criteria include its fixed inverting doubler topology, 12 kHz internal oscillator, 8-pin SOIC package with NC pin, low 185 µA quiescent current, and compatibility with standard 3.3 µF ceramic pump capacitors for space-constrained negative rail generation.

Technical Context

The TC682COA implements a two-phase switched-capacitor charge pump using internal MOSFET switches clocked by a 12 kHz on-chip oscillator. Its functional block integrates charge transfer between C1 and C2 during Phase 1, then transfers stored energy to the reservoir capacitor COUT during Phase 2 to produce VOUT = –2 × VIN.

It features on-chip Zener clamping (VIN ≤ +5.8V, VOUT ≥ –11.6V), supports operation from 0°C to +70°C, and relies on external capacitor ESR and values to determine output resistance (ROUT) and ripple-e.g., ROUT = 140 Ω typ. with 3.3 µF/0.5 Ω ESR capacitors at +25°C.

Key Specifications

Pinout & Package

TC682COA is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package, 3.99 mm × 4.90 mm body size, with standard 1.27 mm pitch and gull-wing leads. Pin 1 is marked by a notch or dot; Pin 8 is NC (no connection) and must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar inverting voltage doubler applications.

Compared with MAX680ESA+ and ICL7660SCPAZ, the TC682COA offers superior efficiency (92% vs. ~85%), lower quiescent current (185 µA vs. 250–350 µA), and higher output drive capability (10 mA vs. 5–8 mA), making it optimal for medium-current portable analog power rails.

Availability

TC682COA is available at Aetrix Electronics and suitable for portable handheld instruments, LCD display bias generation, and operational amplifier power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TC682COA 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

Microchip Technology Inc. is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and power management ICs, with ISO/TS-16949 certified wafer fabrication and design centers worldwide.

The TC682COA belongs to Microchip's legacy charge pump converter product line, designed specifically for compact, inductorless negative voltage generation in battery-powered analog systems and portable instrumentation.

FAQ

What is the maximum input voltage the TC682COA can tolerate?

The TC682COA has absolute maximum ratings of +5.8V on VIN. Exceeding this voltage risks permanent damage due to internal Zener clamping action. The recommended operating range remains +2.4V to +5.5V per datasheet specifications. For reliable long-term operation, VIN should be kept within this range-especially under transient conditions-since sustained clamping dissipates excess power and degrades device reliability. The TC682COA does not include overvoltage shutdown, so external protection may be needed in noisy supply environments.

Can the TC682COA generate a regulated –5V output from a 3V battery?

Yes-the TC682COA outputs approximately –6V from a 3V input (VOUT ≈ –2 × VIN), which can be regulated to –5V using an external negative LDO such as the TC54VC2702Exx. This configuration is explicitly documented in Figure 4-3 of the TC682COA datasheet. With proper capacitor selection (e.g., 3.3 µF pump caps, 10–22 µF reservoir), the TC682COA maintains stable output under 10 mA load, enabling precise –5V bias for analog circuitry in handheld meters and sensors.

What external capacitors are required for basic operation of the TC682COA?

The TC682COA requires exactly three external capacitors: two 3.3 µF low-ESR ceramic pump capacitors (C1 and C2) rated for ≥6VDC (C1) and ≥12VDC (C2), plus one reservoir/output capacitor (COUT) typically 10–22 µF rated ≥12VDC. These values are validated in the datasheet test circuit (Figure 3-1) and ensure 140 Ω typical output resistance and <60 mVpp ripple at 10 mA. Electrolytic capacitors are discouraged due to high ESR, which directly increases ROUT and ripple.

Is the TC682COA pin-compatible with the TC682CPA?

Yes-the TC682COA (8-pin SOIC) and TC682CPA (8-pin PDIP) share identical pin numbering, pin functions, and electrical specifications. Both feature NC on Pin 8, GND on Pin 5, and identical C1+/C1–/C2+/C2– assignments. The only differences are package type (SOIC vs. PDIP), thermal performance (SOIC: 470 mW max power dissipation), and operating temperature grade (both rated 0°C to +70°C). Layout adaptation is required, but schematic and firmware remain unchanged.

How does output source resistance affect TC682COA performance under load?

Output source resistance (ROUT) directly determines voltage droop: VDROP = IOUT × ROUT. With 140 Ω typical ROUT, the TC682COA drops 1.4 V at 10 mA load-so a 3V input yields ~–4.6V instead of ideal –6V. ROUT varies with temperature, capacitor ESR, and pump capacitor value (e.g., 100 µF C1/C2 lowers ROUT to ~87 Ω). Designers must select capacitors with low ESR (<1 Ω) and verify VOUT under worst-case load and temperature to meet system rail tolerance requirements.