Datasheet

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_______________General Description

The MAX1044 and ICL7660 are monolithic, CMOS

switched-capacitor voltage converters that invert, dou-

ble, divide, or multiply a positive input voltage. They are

pin compatible with the industry-standard ICL7660 and

LTC1044. Operation is guaranteed from 1.5V to 10V with

no external diode over the full temperature range. They

deliver 10mA with a 0.5V output drop. The MAX1044

has a BOOST pin that raises the oscillator frequency

above the audio band and reduces external capacitor

size requirements.

The MAX1044/ICL7660 combine low quiescent current

and high efficiency. Oscillator control circuitry and four

power MOSFET switches are included on-chip.

Applications include generating a -5V supply from a

+5V logic supply to power analog circuitry. For applica-

tions requiring more power, the MAX660 delivers up to

100mA with a voltage drop of less than 0.65V.

________________________Applications

-5V Supply from +5V Logic Supply

Personal Communications Equipment

Portable Telephones

Op-Amp Power Supplies

EIA/TIA-232E and EIA/TIA-562 Power Supplies

Data-Acquisition Systems

Hand-Held Instruments

Panel Meters

____________________________Features

♦ Miniature µMAX Package

♦ 1.5V to 10.0V Operating Supply Voltage Range

♦ 98% Typical Power-Conversion Efficiency

♦ Invert, Double, Divide, or Multiply Input Voltages

♦ BOOST Pin Increases Switching Frequencies

(MAX1044)

♦ No-Load Supply Current: 200µA Max at 5V

♦ No External Diode Required for Higher-Voltage

Operation

______________Ordering Information

Ordering Information continued at end of data sheet.

* Contact factory for dice specifications.

MAX1044/ICL7660

Switched-Capacitor Voltage Converters

________________________________________________________________

Maxim Integrated Products

Call toll free 1-800-998-8800 for free samples or literature.

19-4667; Rev 1; 7/94

MAX1044

ICL7660

CAP-

GND

CAP+

(N.C.) BOOST

OUT

OSC

V+

TOP VIEW

( ) ARE FOR ICL7660

DIP/SO/µMAX

TO-99

ICL7660

N.C.

CAP+

GND

CAP-

OUT

OSC

V+ AND CASE

_________________Pin Configurations

NEGATIVE VOLTAGE CONVERTER

CAP+

CAP-

V+

OUT

GND

INPUT

SUPPLY

VOLTAGE

NEGATIVE

OUTPUT

VOLTAGE

MAX1044

ICL7660

__________Typical Operating Circuit

Dice*

8 SO

8 Plastic DIP

PIN-PACKAGETEMP. RANGE

0°C to +70°C

0°C to +70°CMAX1044C/D

MAX1044CSA

MAX1044CPA

PART

8 Plastic DIP-40°C to +85°CMAX1044EPA

Summary of content (12 pages)

PAGE 1
9-4667; Rev 1; 7/94 Switched-Capacitor Voltage Converters ________________________Applications -5V Supply from +5V Logic Supply Personal Communications Equipment Portable Telephones Op-Amp Power Supplies EIA/TIA-232E and EIA/TIA-562 Power Supplies Data-Acquisition Systems Hand-Held Instruments Panel Meters __________Typical Operating Circuit ____________________________Features ♦ Miniature µMAX Package ♦ 1.5V to 10.
PAGE 2
MAX1044/ICL7660 Switched-Capacitor Voltage Converters ABSOLUTE MAXIMUM RATINGS Supply Voltage (V+ to GND, or GND to VOUT)....................10.5V Input Voltage on Pins 1, 6, and 7 .........-0.3V ≤ VIN ≤ (V+ + 0.3V) LV Input Current ..................................................................20µA Output Short-Circuit Duration (V+ ≤ 5.5V)..................Continuous Continuous Power Dissipation (TA = +70°C) Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW SO (derate 5.
PAGE 3
Switched-Capacitor Voltage Converters 150 C V+ = 2V LV = GND -0.5 100 50 OUTPUT RIPPLE 0 0 1 2 3 4 5 6 7 8 9 480 400 C 320 -2.0 C -1.5 V+ = 5V LV = OPEN B 240 -0.
PAGE 4
____________________________Typical Operating Characteristics (continued) (V+ = 5V; CBYPASS = 0.1µF; C1 = C2 = 10µF; LV = open; OSC = open; TA = +25°C; unless otherwise noted.) OSCILLATOR FREQUENCY vs. TEMPERATURE QUIESCENT CURRENT vs.
PAGE 5
Switched-Capacitor Voltage Converters PIN NAME FUNCTION BOOST (MAX1044) Frequency Boost. Connecting BOOST to V+ increases the oscillator frequency by a factor of six. When the oscillator is driven externally, BOOST has no effect and should be left open. N.C. (ICL7660) No Connection 1 2 CAP+ Connection to positive terminal of Charge-Pump Capacitor 3 GND Ground. For most applications, the positive terminal of the reservoir capacitor is connected to this pin.
PAGE 6
S1 current is: I = f x ∆Q = f x C1(V+ - VOUT). Rewriting this equation in Ohm’s law form defines an equivalent resistance synthesized by the switched-capacitor circuit where: S2 V+ (V+ - VOUT ) 1 / (f x C1) and 1 REQUIV = f x C1 I= C1 S3 C2 S4 VOUT = -(V+) where f is one-half the oscillator frequency. This resistance is a major component of the output impedance of switched-capacitor circuits like the MAX1044/ICL7660.
PAGE 7
Switched-Capacitor Voltage Converters C1 10µF 2 3 4 V+ 8 1 MAX1044 ICL7660 7 6 VOUT = -(V+) 1 V+ 8 CBYPASS * C2 10µF 2 MAX1044 7 10µF 3 COSC 6 VOUT = -(V+) 5 4 5 10µF *REQUIRED FOR V+ < 3.5V Figure 5. Basic Negative Voltage Converter Figure 6. Negative Voltage Converter with COSC and BOOST and allow operation down to 1.5V.
PAGE 8
MAX1044/ICL7660 Switched-Capacitor Voltage Converters V+ 1 2 10µF 10kΩ REQUIRED FOR TTL CMOS or V+ TTL GATE 8 MAX1044 ICL7660 7 3 6 4 5 VOUT = -(V+) 10µF switching noise and EMI may be generated. To reduce these effects: 1) Power the MAX1044/ICL7600 from a low-impedance source. 2) Add a power-supply bypass capacitor with low effective series resistance (ESR) close to the IC between the V+ and ground pins. 3) Shorten traces between the IC and the charge-pump capacitors.
PAGE 9
Switched-Capacitor Voltage Converters 1 2 PCONV.LOSS =  C1  (V+ ) 2 − VOUT  +   2  1 2 C2  VRIPPLE − 2VOUT VRIPPLE   x fOSC / 2   2 Increasing Efficiency Efficiency can be improved by lowering output voltage ripple and output impedance. Both output voltage ripple and output impedance can be reduced by using large capacitors with low ESR. The output voltage ripple can be calculated by noting that the output current is supplied solely from capacitor C2 during one-half of the charge-pump cycle.
PAGE 10
MAX1044/ICL7660 Switched-Capacitor Voltage Converters V+ V+ C1 10µF 1 8 1 2 7 2 3 MAX1044 ICL7660 LV 4 C3 LV 4 5 VOUT = -(V+) 7 MAX1044 ICL7660 3 C1 6 8 6 5 VOUT = 2(V+) - 2VD VOUT = 1 V+ 2 C2 10µF C2 Figure 10. Voltage Divider Figure 11. Combined Positive and Negative Converter capacitors for the doubled positive voltage. This circuit has higher output impedances resulting from the use of a common charge-pump driver.
PAGE 11
Switched-Capacitor Voltage Converters 1 2 C1 V+ 8 7 MAX1044 ICL7660 3 6 4 ROUT = 5 ROUT (of MAX1044 or ICL7660) n (number of devices) 1 Shutdown Schemes 1 8 2 C1 7 MAX1044 ICL7660 3 VOUT = -(V+) 6 4 C2 5 n Figures 14a–14c illustrate three ways of adding shutdown capability to the MAX1044/ICL7660. When using these circuits, be aware that the additional capacitive loading on the OSC pin will reduce the oscillator frequency.
PAGE 12
MAX1044/ICL7660 Switched-Capacitor Voltage Converters __________________________________________________________Chip Topographies MAX1044 GND CAP+ ICL7660 BOOST V+ 0.084" (2.1mm) CAP+ 0.076" (1.930mm) GND OSC CAPCAPV+ LV V OUT V OUT LV OSC 0.060" (1.5mm) 0.076" (1.930mm) TRANSISTOR COUNT: 72 SUBSTRATE CONNECTED TO V+ TRANSISTOR COUNT: 71 SUBSTRATE CONNECTED TO V+ ________________________________________________________Package Information DIM E A A1 B C D E e H L α H INCHES MAX MIN 0.