19-0191; Rev 1; 3/94
-5V/-12V/-15V or Adjus ta ble ,
High-Effic ie nc y, Low I Inve rting DC-DC Controlle rs
Q
45/MAX76
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
♦ 85% Efficiency for 5mA to 1A Load Currents
♦ Up to 5W Output Power
The MAX774/MAX775/MAX776 inve rting s witc hing
regulators deliver high efficiency over three decades of
loa d c urre nt. A uniq ue c urre nt-limite d , p uls e -
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.
♦ 100µA Max Supply Current
♦ 5µA Max Shutdown Current
♦ 3V to 16.5V Input Range
♦ -5V (MAX774), -12V (MAX775), -15V (MAX776),
or Adjustable Output Voltage
These ICs also use tiny external components; their high
switching frequency (up to 300kHz) allows for less than
5mm diameter surface-mount magnetics.
♦ Current-Limited PFM Control Scheme
♦ 300kHz Switching Frequency
The MAX774/MAX775/MAX776 accept input voltages from
3V to 16.5V, a nd ha ve p re s e t outp ut volta g e s of
-5V, -12V, and -15V, respectively. Or, the output voltage
c a n b e us e r-a d jus te d with two re s is tors . Ma ximum
______________Ord e rin g In fo rm a t io n
V
- V
differential voltage is limited only by the break-
IN
OUT
down voltage of the chosen external switch transistor.
PART
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
8 Plastic DIP
8 SO
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.
MAX774CPA
MAX774CSA
MAX774C/D
MAX774EPA
MAX774ESA
MAX774MJA
0°C to +70°C
0°C to +70°C
Dice*
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
8 Plastic DIP
8 SO
________________________Ap p lic a t io n s
LCD-Bias Generators
8 CERDIP
Ordering Information continued on last page.
* Contact factory for dice specifications.
High-Efficiency DC-DC Converters
Battery-Powered Applications
Data Communicators
__________Typ ic a l Op e ra t in g Circ u it
__________________P in Co n fig u ra t io n
INPUT
3V TO 16V
TOP VIEW
V+
MAX774
CS
1
2
3
4
OUT
FB
8
GND
EXT
SHDN
ON/OFF
7
P
MAX774
MAX775
MAX776
EXT
OUTPUT
-5V
SHDN
REF
6
5
CS
V+
FB
REF
DIP/SO
OUT
GND
________________________________________________________________ Maxim Integrated Products
1
Ca ll t o ll fre e 1 -8 0 0 -9 9 8 -8 8 0 0 fo r fre e s a m p le s o r lit e ra t u re .