TC7660 Charge Pump DC-to-DC Voltage Converter

TC7660 is an 8 pin IC used as the voltage regulator. The ICL7660 is an industry-standard replacement of 7660 operating pump voltage converters that is pin compatible. The signal is transformed into an impedance of + 1.5V to+ 10V, using only two low-cost ceramic capacitors to reduce costs, sizes and electromagnetic interference (EMI) related to inductors. It is also available in the market with the name of ICL7660.

TC7660 Pinout Diagram

TC7660 charge pump dc to dc voltage converter IC has 8 pins.  Pin7 is used only when lowers than 10KHz frequency operation required.

TC7660 voltage regulator pinout diagram

Pin configuration Description

Pin1: NC

NC pins mean no connection pin. The pins on separate integrated circuit packs are Not Connected terminals. Such pins are not meant for the outside circuit (though their functionalities may not be exposed). The chip factory suppliers manufacturing plant can only accommodate several different packages, so no one can be available with the right number of pins so that you can raise a size. Such pins should not be attached to any of the circuit links, i.e. should be left floating.

Pin2: Cap+

The CAP+ pin is basically a positive terminal of charge pump capacitor pin. This is a positive terminal of the charge pump capacitor which handles the charge transference between the input and output terminal. While using this IC as the voltage regulator, the CAP+ is calibrated to the input voltage for the first half of the switching phase. The CAP is inverted, and load and charge are passed to the capacitor at the output during the second half of the switching phase.

Pin3: GND

It is the ground pin.

Pin4: CAP-

This pin is the negative output source of the charge pump capacitor.  It functions while voltage regulation. During the first half of the switching phase, the CAP capacitor provides the charge at output source. The load is returned to the output CAP capacitor pin during the second half of the switching process.

Pin5: Vout

It provides a negative source to the CAP capacitor source.

Pin6: LV

The low voltage pin guarantees that the internal oscillator is working properly with input voltages below 3.5V.

Pin7: OSC

It is the oscillator control input pin. Its main purpose is to slow or speed up the operation of the TC7660, the oscillator control input can be used. Bypass to interrupt the oscillator by an active capacitor.

Pin8: V+

It is the pin used for supplying power to IC. Low equivalent resistor connected in series is recommended to be used for bypassing the power supply provided at input towards the output source.

Operating Frequency Selection

The on-board oscillator currently operates at a peak frequency of 10 kHz. An external capacitor can be attached from OSC to operate below 10 kHz (for the lower power supply applications).

TC7660 DC to DC Converter Features

Following are the main features of the TC7660:

  • Maximum and minimum Input Voltage is 1.5V and 10V
  • The adjustable output voltage range is from -10V to -1.5V
  • Power consumption is very low and is typically 80 µA
  • Improved ESD protection of up to 3kV.
  • Only two external capacitors are required therefore it is easy to use
  • Voltage Conversion efficiency is 99.9%

Where to use it?

As it is Voltage Converter IC therefore, it is used in voltage conversion applications. It is very efficient for use in linear circuits due to the capability of performing voltage regulation through switching. You can use it in designing DC to DC converters and voltage inversion circuits.

How to use TC7660?

It can be used as a simple negative voltage regulator. The following connections show how we can obtain a negative voltage by providing a positive voltage on the input terminal. The pin connections are discussed in detail in the above section.

TC7660 voltage regulator Example circuit

For the supply voltages of + 1.5V to + 10V, a similar system may be used, considering that pin 6 (LV) is connected to a negative power supply (DC) only with supply voltages less than 3.5 volts. Multiple IC’s can be cascaded to achieve larger negative multiplication of the initial supply voltage.

Example Circuit with Proteus simulation

This circuit shows TC7660 -12 volts supply example circuit. We use a proteus simulator to design this circuit. As you can see fro the diagram that we get the same exact voltage at the output but having an opposite polarity.

TC7660 -12 volts supply example circuit with proteus simulation


  • Positive and Negative voltage multiplication
  • Simple Conversion of +5V to ±5V Supplies
  • RS-232 Negative Power Supply
  • Data Acquisition Systems and Instrumentation

ICL7660 Equivalents

  • LM27762
  • LM2776
  • TPS60401

2D Diagram

The two-dimensional diagram of the SOIC package is given. For other packages detail, refer to the datasheet.

Negative voltage regulator 2D diagram


TC7660 charge pump DC to DC Converter datasheet

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