LT1109_15 Datasheet, PDF (1/8 Pages) Linear Technology – Micropower Low Cost DC/DC Converter Adjustable and Fixed 5V, 12V

FEATURES
s _{Uses Off-the-Shelf Inductors}
s _{Only 33µH Inductor Required}
s _{Low Cost}
s _{3-Lead TO-92, SO8, or 8-Pin DIP}
s _{Adjustable or Fixed 5V or 12V Output}
s _{120kHz Oscillator}
s _{Only Three External Components Required}
s _{320µA IQ}
s _{1.6V Minimum Start-Up Voltage}
s _{Logic Controlled Shutdown}
APPLICATI S
s _{Flash Memory VPP Generators}
s _{3V to 5V Converters}
s _{5V to 12V Converters}
s _{Disk Drives}
s _{PC Plug-In Cards}
s _Peripherals
s _{Battery-Powered Equipment}
LT110 9
Micropower Low Cost
DC/DC Converter
Adjustable and Fixed 5V, 12V
DESCRIPTIO
The LT1109 is a simple step-up DC/DC converter. Avail-
able in 8-pin SO, 3-lead TO-92 (fixed output only) or
miniDIP packages, the devices require only three external
components to construct a complete DC/DC converter.
Current drain is just 320µA at no load, making the device
ideal for cost-sensitive applications where standby cur-
rent must be kept to a minimum.
The LT1109-5 can deliver 5V at 100mA from a 3V input
and the LT1109-12 can deliver 12V at 60mA from a 5V
input. The 8-pin versions also feature a logic controlled
SHUTDOWN pin that turns off the oscillator when taken
low. The gated-oscillator design requires no frequency
compensation components. The high frequency 120kHz
oscillator permits the use of small surface mount induc-
tors and capacitors. For a 5V to 12V at 120mA converter,
see the LT1109A. Foa a 5V to 12V at 200mA converter
with 20µA shutdown current, see the LT1301.
TYPICAL APPLICATI
All Surface Mount
Flash Memory VPP Generator
L1^¦
33µH
MBRS120T3
V_IN
5V
SHUTDOWN
1
V_IN
3
SW
8
SENSE
LT1109CS8-12
7
+
SHUTDOWN*
GND
4
PROGRAM
V_OUT
12V
80mA
C1**
22µF
16V
* 8-PIN PACKAGE ONLY
¦ _{L1 = SUMIDA CD54-330LC (IOUT = 80mA)}
COILTRONICS CTX33-1 (80mA)
MURATA-ERIE LQH4N330K (I
OUT ^{= 50mA)}
ISI LCS2414-330K (I_OUT = 50mA)
**C1 = MATSUO 267M1602226 OR EQUIVALENT
LT1109 • TA01
Output Voltage
15
V_IN = 5V
12
Flash Memory Program Output
V_OUT
5V/DIV
OV
9
SHUTDOWN
5V/DIV
6
1ms/DIV
LT1109 • TA02
3
0
0 10 20 30 40 50 60 70 80 90 100
OUTPUT CURRENT (mA)
LT1109 • TPC01
1