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TC1044S

TC1044S-12 9/16/96

EVALUATION

KIT

AVAILABLE

Charge Pump DC-TO-DC Voltage Converter

FEATURES

■ Converts +5V Logic Supply to ±5V System

■ Wide Input Voltage Range ....................1.5V to 12V

■ Efficient Voltage Conversion.........................99.9%

■ Excellent Power Efficiency ...............................98%

■ Low Power Consumption ............ 80µA @ V

= 5V

■ Low Cost and Easy to Use

— Only Two External Capacitors Required

■ RS-232 Negative Power Supply

■ Available in 8-Pin Small Outline (SOIC) and 8-Pin

Plastic DIP Packages

■ Improved ESD Protection ..................... Up to 10kV

■ No External Diode Required for High Voltage

Operation

■ Frequency Boost Raises F

OSC

to 45kHz

GENERAL DESCRIPTION

The TC1044S is a pin-compatible upgrade to the Indus-

try standard TC7660 charge pump voltage converter. It

converts a +1.5V to +12V input to a corresponding –1.5V

to –12V output using only two low cost capacitors, eliminat-

ing inductors and their associated cost, size and EMI.

Added features include an extended supply range to 12V,

and a frequency boost pin for higher operating frequency,

allowing the use of smaller external capacitors.

The on-board oscillator operates at a nominal frequency

of 10kHz. Frequency is increased to 45kHz when pin 1 is

connected to V

. Operation below 10kHz (for lower supply

current applications) is possible by connecting an external

capacitor from OSC to ground (with pin 1 open).

The TC1044S is available in both 8-pin DIP and

8-pin small outline (SOIC) packages in commercial and

extended temperature ranges.

FUNCTIONAL BLOCK DIAGRAM

TC1044S

GND

INTERNAL

VOLTAGE

REGULATOR

OSCILLATOR

VOLTAGE–

LEVEL

TRANSLATOR

CAP

OSC

LOGIC

NETWORK

OUT

CAP

–

BOOST

ORDERING INFORMATION

Part No. Package Temp. Range

TC1044SCOA 8-Pin SOIC 0°C to +70°C

TC1044SCPA 8-Pin Plastic DIP 0°C to +70°C

TC1044SEOA 8-Pin SOIC – 40°C to +85°C

TC1044SEPA 8-Pin Plastic DIP – 40°C to +85°C

TC1044SIJA 8-Pin CerDIP – 25°C to +85°C

TC1044SMJA 8-Pin CerDIP – 55°C to +125°C

TC7660EV Charge Pump Family Evaluation Kit

PIN CONFIGURATION (DIP AND SOIC)

TC1044SCPA

TC1044SEPA

TC1044SIJA

TC1044SMJA

BOOST

CAP

GND

CAP

–

OUT

LOW

VOLTAGE (LV)

OSC

TC1044SCOA

TC1044SEOA

BOOST

CAP

GND

CAP

–

OUT

LOW

VOLTAGE (LV)

OSC

Summary of content (11 pages)

PAGE 1
EVALUATION KIT AVAILABLE TC1044S Charge Pump DC-TO-DC Voltage Converter FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ GENERAL DESCRIPTION Converts +5V Logic Supply to ±5V System Wide Input Voltage Range .................... 1.5V to 12V Efficient Voltage Conversion ......................... 99.9% Excellent Power Efficiency ............................... 98% Low Power Consumption ............
PAGE 2
Charge Pump DC-TO-DC Voltage Converter TC1044S Package Power Dissipation (TA ≤ 70°C) (Note 2) 8-Pin CerDIP .................................................. 800mW 8-Pin Plastic DIP ............................................. 730mW 8-Pin SOIC .....................................................470mW Operating Temperature Range C Suffix .................................................. 0°C to +70°C I Suffix ............................................... – 25°C to +85°C E Suffix ........................
PAGE 3
Charge Pump DC-TO-DC Voltage Converter TC1044S Circuit Description V+ The TC1044S contains all the necessary circuitry to implement a voltage inverter, with the exception of two external capacitors, which may be inexpensive 10 µF polarized electrolytic capacitors. Operation is best understood by considering Figure 2, which shows an idealized voltage inverter. Capacitor C1 is charged to a voltage, V+, for the half cycle when switches S1 and S3 are closed.
PAGE 4
Charge Pump DC-TO-DC Voltage Converter TC1044S Dos and Don'ts The output characteristics of the circuit in Figure 3 are those of a nearly ideal voltage source in series with 70Ω. Thus, for a load current of –10mA and a supply voltage of +5V, the output voltage would be – 4.3V. The dynamic output impedance of the TC1044S is due, primarily, to capacitive reactance of the charge transfer capacitor (C1). Since this capacitor is connected to the output for only 1/2 of the cycle, the equation is: 2 XC = = 3.
PAGE 5
Charge Pump DC-TO-DC Voltage Converter TC1044S V+ 1 8 2 7 1 TC1044S + 3 10µF 6 4 "1" 2 + 5 10µF 8 TC1044S 3 4 7 6 "n" 5 VOUT* + * NOTES: 1. VOUT = –n(V+) for 1.5V ≤ V+ ≤ 12V 10µF 10µF + Figure 5. Increased Output Voltage by Cascading Devices Cascading Devices situation where the designer has generated the external clock frequency using TTL logic, the addition of a 10kΩ pullup resistor to V+ supply is required.
PAGE 6
Charge Pump DC-TO-DC Voltage Converter TC1044S V C1 + 1 8 2 7 3 TC1044S 4 will bypass the other (D1 and D2 in Figure 9 would never turn on), or else the diode and resistor shown dotted in Figure 10 can be used to "force" the internal regulator on. + COSC Voltage Splitting 6 5 The same bidirectional characteristics used in Figure 10 can also be used to split a higher supply in half, as shown in Figure 11. The combined load will be evenly shared between the two sides.
PAGE 7
Charge Pump DC-TO-DC Voltage Converter TC1044S V+ VOUT = –V– + C1 10µF 1 8 2 7 3 TC1044S 4 + 1 MΩ 6 1 8 2 VOUT = + V + –V – 50 2 µF RL2 10µF + 50 µF RL1 3 100 kΩ 100 kΩ 7 1 MΩ TC1044S 6 4 5 5 50 µF V– INPUT + V– Figure 10. Positive Voltage Conversion Figure 11. Splitting a Supply in Half TYPICAL CHARACTERISTICS Unloaded Osc Freq vs. Temperature Unloaded Osc Freq vs.
PAGE 8
Charge Pump DC-TO-DC Voltage Converter TC1044S TYPICAL CHARACTERISTICS (Cont.) Output Source Resistance vs. Supply Voltage Output Source Resistance vs. Temperature 100 OUTPUT SOURCE RESISTANCE (Ω) OUTPUT SOURCE RESISTANCE (Ω) 100 70 50 30 IOUT = 20mA TA = 25°C 10 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12 VIN = 2.5V 80 60 VIN = 5.5V 40 20 0 -40 -20 SUPPLY VOLTAGE (V) 0 20 40 Output Voltage vs. Output Current 80 100 Power Conversion Efficiency vs.
PAGE 9
Charge Pump DC-TO-DC Voltage Converter TC1044S PACKAGE DIMENSIONS 8-Pin Plastic DIP PIN 1 .260 (6.60) .240 (6.10) .045 (1.14) .030 (0.76) .070 (1.78) .040 (1.02) .310 (7.87) .290 (7.37) .400 (10.16) .348 (8.84) .200 (5.08) .140 (3.56) .040 (1.02) .020 (0.51) .015 (0.38) .008 (0.20) .150 (3.81) .115 (2.92) .110 (2.79) .090 (2.29) 3° MIN. .400 (10.16) .310 (7.87) .022 (0.56) .015 (0.38) 8-Pin CerDIP .110 (2.79) .090 (2.29) PIN 1 .300 (7.62) .230 (5.84) .020 (0.51) MIN. .055 (1.40) MAX. .
PAGE 10
Charge Pump DC-TO-DC Voltage Converter TC1044S PACKAGE DIMENSIONS (CONT.) 8-Pin SOIC .157 (3.99) .150 (3.81) .244 (6.20) .228 (5.79) .050 (1.27) TYP. .197 (5.00) .189 (4.80) .069 (1.75) .053 (1.35) .010 (0.25) .007 (0.18) 8° MAX. .020 (0.51) .010 (0.25) .013 (0.33) .004 (0.10) .050 (1.27) .016 (0.40) Dimensions: inches (mm) TC1044S-12 9/16/96 10 © 2001 Microchip Technology Inc.
PAGE 11
Charge Pump DC-TO-DC Voltage Converter TC1044S WORLDWIDE SALES AND SERVICE AMERICAS New York ASIA/PACIFIC (continued) Corporate Office 150 Motor Parkway, Suite 202 Hauppauge, NY 11788 Tel: 631-273-5305 Fax: 631-273-5335 Singapore 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: 480-792-7627 Web Address: http://www.microchip.com Rocky Mountain 2355 West Chandler Blvd.