19-0191; Rev 1; 3/94
TION KIT
EVALUA
LE
AVAILAB
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
Inverting DC-DC Controllers
_______________General Description
The MAX774/MAX775/MAX776 inverting switching
regulators deliver high efficiency over three decades of
load current. A unique current-limited, pulse-
frequency-modulated (PFM) control scheme provides
the benefits of pulse-width modulation (high efficiency
with heavy loads), while using less than 100µA of sup-
ply current (vs. 2mA to 10mA for PWM converters). The
result is high efficiency over a wide range of loads.
These ICs also use tiny external components; their high
switching frequency (up to 300kHz) allows for less than
5mm diameter surface-mount magnetics.
The MAX774/MAX775/MAX776 accept input voltages from
3V to 16.5V, and have preset output voltages of
-5V, -12V, and -15V, respectively. Or, the output voltage
can be user-adjusted with two resistors. Maximum
V
IN
- V
OUT
differential voltage is limited only by the break-
down voltage of the chosen external switch transistor.
These inverters use external P-channel MOSFET switch-
es, allowing them to power loads up to 5W. If less
power is required, use the MAX764/MAX765/MAX766
inverting switching regulators with on-board MOSFETs.
____________________________Features
o
85% Efficiency for 5mA to 1A Load Currents
o
Up to 5W Output Power
o
100µA Max Supply Current
o
5µA Max Shutdown Current
o
3V to 16.5V Input Range
o
-5V (MAX774), -12V (MAX775), -15V (MAX776),
or Adjustable Output Voltage
o
Current-Limited PFM Control Scheme
o
300kHz Switching Frequency
MAX774/MAX775/MAX776
______________Ordering Information
PART
MAX774CPA
MAX774CSA
MAX774C/D
MAX774EPA
MAX774ESA
MAX774MJA
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP
________________________Applications
LCD-Bias Generators
High-Efficiency DC-DC Converters
Battery-Powered Applications
Data Communicators
Ordering Information continued on last page.
* Contact factory for dice specifications.
__________Typical Operating Circuit
INPUT
3V TO 16V
V+
__________________Pin Configuration
TOP VIEW
MAX774
ON/OFF
SHDN
CS
EXT
P
OUT
FB
1
2
3
4
8
GND
EXT
CS
V+
OUTPUT
-5V
SHDN
REF
FB
REF
GND
OUT
MAX774
MAX775
MAX776
7
6
5
DIP/SO
________________________________________________________________
Maxim Integrated Products
1
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