LT1109A Datasheet, PDF (1/8 Pages) Linear Technology – Micropower DC/DC Converter Flash Memory VPP Generator Adjustable and Fixed 5V, 12V

LT1109A
Micropower
DC/DC Converter
Flash Memory VPP Generator
Adjustable and Fixed 5V, 12V
FEATURES
s _{Uses Off-the-Shelf Inductors}
s _{Low Cost}
s _{8-Pin DIP or SO Package}
s _{Fixed 5V or 12V Output or Adjustable Version}
s _{Only Four External Components Required}
s _{360µA Standby Current}
s _{Logic-Controlled Shutdown}
APPLICATI S
s _{Flash Memory VPP Generators}
s _{5V to 12V Converters}
s _{3.3V to 12V Converters}
s _{Disk Drives}
s _{PC Plug-In Cards}
s _Peripherals
s _{Battery-Powered Equipment}
DESCRIPTIO
The LT1109A is a simple step-up DC/DC converter. The 8-
pin DIP or SOIC devices require only four external compo-
nents to construct a complete DC/DC converter. Current
drain is just 360µA at no load, making the device ideal for
cost-sensitive applications where standby current must
be kept to a minimum.
The LT1109A-12 can deliver 12V at over 150mA from a 5V
supply, enough power to program four flash memory
chips simultaneously. The LT1109A-5 can deliver 5V at up
to 110mA from a 2V input. The devices feature a shutdown
pin that turns off the oscillator when taken low. The gated-
oscillator design requires no frequency compensation
components. High frequency 120kHz operation permits
the use of small surface mount inductors and capacitors.
TYPICAL APPLICATI
All Surface Mount
Flash Memory VPP Generator
+V_IN
5V
C1
22µF
10V
L1*
33µH
MBRS130T3
1 _VIN
3
SW
8
SENSE
+
LT1109ACS8-12 ₊
7 _SHUTDOWN
PGND GND
**
4
5
V_OUT
12V
C2
47µF
20V
* COILTRONICS CTX33-2
SUMIDA CD54-330LC
** 1 = PROGRAM
0 = SHUTDOWN
1109A TA01
Output Current
13.0
12V
12.5
V_OUT
V_IN = 5V
2V/DIV
12.0
11.5
SHUTDOWN
V_IN = 4.5V
5V/DIV
11.0
10.5
10.0
0
50 100 150 200 250 300
OUTPUT CURRENT (mA)
1109A TA02
Output Voltage
500µs/DIV
1109A TA03
1