Datasheet

ManualsBrandsMicrochip ManualsDC / DC ControllersDC/DC Converter -1.5 ... -10V 20mA SOIC

 2002-2011 Microchip Technology Inc. DS21465C-page 1

TC7660

Features

• Wide Input Voltage Range: +1.5V to +10V

• Efficient Voltage Conversion (99.9%, typ)

• Excellent Power Efficiency (98%, typ)

• Low Power Consumption: 80 µA (typ) @ V

= 5V

• Low Cost and Easy to Use

- Only Two External Capacitors Required

• Available in 8-Pin Small Outline (SOIC), 8-Pin

PDIP and 8-Pin CERDIP Packages

• Improved ESD Protection (3 kV HBM)

• No External Diode Required for High-Voltage

Operation

Applications

• RS-232 Negative Power Supply

• Simple Conversion of +5V to ±5V Supplies

• Voltage Multiplication V

OUT

= ± n V

• Negative Supplies for Data Acquisition Systems

and Instrumentation

Package Types

General Description

The TC7660 device is a pin-compatible replacement

for the industry standard 7660 charge pump voltage

converter. It converts a +1.5V to +10V input to a corre-

sponding -1.5V to -10V output using only two low-cost

capacitors, eliminating inductors and their associated

cost, size and electromagnetic interference (EMI).

The on-board oscillator operates at a nominal fre-

quency of 10 kHz. Operation below 10 kHz (for lower

supply current applications) is possible by connecting

an external capacitor from OSC to ground.

The TC7660 is available in 8-Pin PDIP, 8-Pin Small

Outline (SOIC) and 8-Pin CERDIP packages in

commercial and extended temperature ranges.

Functional Block Diagram

TC7660

CAP

GND

CAP

OUT

LOW

VOLTAGE (LV)

OSC

PDIP/CERDIP/SOIC

TC7660

GND

Internal

Voltage

Regulator

Oscillator

Voltage

Level

Translator

CAP

OSC

Logic

Network

OUT

CAP-



Internal

Voltage

Regulator

Charge Pump DC-to-DC Voltage Converter

Summary of content (20 pages)

PAGE 1
TC7660 Charge Pump DC-to-DC Voltage Converter Features Package Types • • • • • Wide Input Voltage Range: +1.5V to +10V Efficient Voltage Conversion (99.
PAGE 2
TC7660 1.0 ELECTRICAL CHARACTERISTICS * Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational sections of this specification is not intended. Exposure to maximum rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings* Supply Voltage ..............................................
PAGE 3
TC7660 2.0 TYPICAL PERFORMANCE CURVES Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
PAGE 4
TC7660 0 5 -1 4 -2 3 OUTPUT VOLTAGE (V) -3 -4 -5 -6 -7 -8 0 -1 -2 -3 SLOPE 55Ω LV OPEN -5 10 FIGURE 2-7: Current. 20 30 40 50 60 70 80 90 100 OUTPUT CURRENT (mA) 0 Output Voltage vs. Output 100 20 18 80 16 70 14 60 12 50 10 40 8 30 6 20 4 10 2 0 0 9.0 1.5 3.0 4.5 6.0 7.5 LOAD CURRENT (mA) SUPPLY CURRENT (mA) V+ = 2V 90 FIGURE 2-8: Supply Current and Power Conversion Efficiency vs. Load Current. 2 10 FIGURE 2-10: Current.
PAGE 5
TC7660 3.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 3-1. TABLE 3-1: 3.1 PIN FUNCTION TABLE Pin No. Symbol 1 NC 2 CAP+ Charge pump capacitor positive terminal 3 GND Ground terminal 4 CAP- Charge pump capacitor negative terminal 5 VOUT Output voltage 6 LV 7 OSC 8 V+ Description No connection Low voltage pin. Connect to GND for V+ < 3.5V Oscillator control input.
PAGE 6
TC7660 4.0 DETAILED DESCRIPTION 4.1 Theory of Operation 1 R OUT = ----------------------------- + 8R SW + 4ESR C1 + ESR C2 fPUMP  C1 The TC7660 charge pump converter inverts the voltage applied to the V + pin. The conversion consists of a twophase operation (Figure 4-1). During the first phase, switches S2 and S4 are open and switches S1 and S3 are closed. C1 charges to the voltage applied to the V + pin, with the load current being supplied from C2.
PAGE 7
TC7660 5.0 APPLICATIONS INFORMATION 5.2 5.1 Simple Negative Voltage Converter To reduce the value of ROUT, multiple TC7660 voltage converters can be connected in parallel (Figure 5-2). The output resistance will be reduced by approximately a factor of n, where n is the number of devices connected in parallel. Figure 5-1 shows typical connections to provide a negative supply where a positive supply is available. A similar scheme may be employed for supply voltages anywhere in the operating range of +1.
PAGE 8
TC7660 5.4 Changing the TC7660 Oscillator Frequency The operating frequency of the TC7660 can be changed in order to optimize the system performance. The frequency can be increased by over-driving the OSC input (Figure 5-4). Any CMOS logic gate can be utilized in conjunction with a 1 k series resistor. The resistor is required to prevent device latch-up. While TTL level signals can be utilized, an additional 10 k pull-up resistor to V+ is required.
PAGE 9
TC7660 V+ 1 2 3 + C1 VOUT = -V+ 8 TC7660 4 7 D1 6 + C3 VOUT = D2 (2 V+) - (2 VF) 5 + + C2 C4 FIGURE 5-7: Combined Negative Converter and Positive Multiplier. 5.7 Efficient Positive Voltage Multiplication/Conversion Since the switches that allow the charge pumping operation are bidirectional, the charge transfer can be performed backwards as easily as forwards. Figure 5-8 shows a TC7660 transforming -5V to +5V (or +5V to +10V, etc.).
PAGE 10
TC7660 6.0 PACKAGING INFORMATION 6.1 Package Marking Information 8-Lead PDIP (300 mil) XXXXXXXX XXXXXNNN YYWW 8-Lead CERDIP (.300”) XXXXXXXX XXXXXNNN YYWW 8-Lead SOIC (3.90 mm) NNN Legend: XX...
PAGE 11
TC7660 4 & ' !& " & 5 && 366*** ' '6 # * !( 5 ! ! & 5 % & & # & N NOTE 1 E1 1 3 2 D E A2 A L A1 c e eB b1 b 7 &! ' ! : ' &! 8"') % ! 8,9. 8 8 8; < = & 2 , & & > > 1 - 1 1 > > " # & " # ? #& . - - 1 # # 5 .
PAGE 12
TC7660 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging DS21465C-page 12  2002-2011 Microchip Technology Inc.
PAGE 13
TC7660 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging  2002-2011 Microchip Technology Inc.
PAGE 14
TC7660 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging DS21465C-page 14  2002-2011 Microchip Technology Inc.
PAGE 15
TC7660 ! " " ## $% &' !" ( 4 & ' !& " & 5 && 366*** ' '6  2002-2011 Microchip Technology Inc.
PAGE 16
TC7660 APPENDIX A: REVISION HISTORY Revision C (March 2012) The following is the list of modifications. 1. 2. Updated Figure 5-5. Added Appendix A. Revision B (March 2003) Undocumented changes. Revision A (May 2002) Original release of this document. DS21465C-page 16  2002-2012 Microchip Technology Inc.
PAGE 17
TC7660 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO.
PAGE 18
TC7660 NOTES: DS21465C-page 18  2002-2012 Microchip Technology Inc.
PAGE 19
Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature.
PAGE 20
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