Rainbow Electronics MAX776 - Manual

_______________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.
________________________Applications
LCD-Bias Generators
High-Efficiency DC-DC Converters
Battery-Powered Applications
Data Communicators
____________________________Features
♦ 85% Efficiency for 5mA to 1A Load Currents
♦ Up to 5W Output Power
♦ 100µA Max Supply Current
♦ 5µA Max Shutdown Current
♦ 3V to 16.5V Input Range
♦ -5V (MAX774), -12V (MAX775), -15V (MAX776),
or Adjustable Output Voltage
♦ Current-Limited PFM Control Scheme
♦ 300kHz Switching Frequency
______________Ordering Information
Ordering Information continued on last page.
* Contact factory for dice specifications.
MAX774/MAX775/MAX776
-5V/-12V/-15V or Adjustable,
High-Efficiency, Low I
Q
Inverting DC-DC Controllers
________________________________________________________________ Maxim Integrated Products 1
1
2
3
4 5
8
7
6
MAX774
MAX775
MAX776
DIP/SO
TOP VIEW
GND
EXT
CS
V+
OUT
FB
SHDN
REF
__________________Pin Configuration
MAX774
OUTPUT
-5V
REF
SHDN
GND
V+
CS
EXT
OUT
ON/OFF
INPUT
3V TO 16V
P
FB
__________Typical Operating Circuit
Call toll free 1-800-998-8800 for free samples or literature.
PART TEMP. RANGE PIN-PACKAGE
MAX774 CPA 0°C to +70°C 8 Plastic DIP
MAX774CSA 0°C to +70°C 8 SO
MAX774C/D 0°C to +70°C Dice*
MAX774EPA -40°C to +85°C 8 Plastic DIP
MAX774ESA -40°C to +85°C 8 SO
MAX774MJA -55°C to +125°C 8 CERDIP
19-0191; Rev 1; 3/94
EVALUATION KIT
AVAILABLE