19-1334; Rev 0; 1/98
Regulated, 125mA-Output,
Charge-Pump DC-DC Inverter
________________General Description
The MAX1673 charge-pump inverter provides a low-
cost, compact means of generating a regulated nega-
tive output from a positive input at up to 125mA. It
requires only three small capacitors, and only two resis-
tors to set its output voltage. The input range is 2V to
5.5V. The regulated output can be set from 0V to -V
IN
in
Skip regulation mode or -1.5V to -V
IN
in Linear (LIN)
regulation mode.
In Skip mode, the MAX1673 regulates by varying its
switching frequency as a function of load current. This
On-Demand™ switching gives the MAX1673 two
advantages: very small capacitors and very low quies-
cent supply current. At heavy loads, it transfers energy
from the input to the output by switching at up to
350kHz. It switches more slowly at light loads, using
only 35µA quiescent supply current.
In Linear mode, the MAX1673 switches at a constant
350kHz at all loads and regulates by controlling
the current-path resistance. This provides constant-
frequency ripple, which is easily filtered for low-noise
applications.
This device also features a 1µA logic-controlled shut-
down mode and is available in a standard 8-pin SO
package. For a device that delivers about 10mA and
fits in a smaller package, refer to the MAX868.
____________________________Features
o
Regulated Negative Output Voltage
(up to -1 x V
IN
)
o
125mA Output Current
o
35µA Quiescent Supply Current
(Skip-mode regulation)
o
350kHz Fixed-Frequency, Low-Noise Output
(Linear-mode regulation)
o
2V to 5.5V Input Range
o
1µA Logic-Controlled Shutdown
MAX1673
_______________Ordering Information
PART
MAX1673ESA
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
8 SO
________________________Applications
Hard Disk Drives
Camcorders
Analog Signal-Processing
Applications
Measurement Instruments
Modems
Digital Cameras
Typical Operating Circuit
INPUT 2V TO 5.5V
___________________Pin Configuration
TOP VIEW
LIN/SKIP
CAP+
CAP-
1
2
8
7
IN
CAP+
GND
FB
OUT
CAP-
LIN/SKIP
GND
ON
OFF
SHDN
IN
FB
REGULATED
NEGATIVE
OUTPUT
(UP TO -1 x V
IN
,
UP TO 125mA)
MAX1673
OUT
MAX1673
3
6
5
SHDN
4
SO
On-Demand™ is a trademark of Maxim Integrated Products.
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
