Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

LT1109 Datasheet(PDF) 4 Page - Linear Technology

Part No. LT1109
Description  Micropower Low Cost DC/DC Converter Adjustable and Fixed 5V, 12V
Download  8 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  LINER [Linear Technology]
Homepage  http://www.linear.com
Logo 

LT1109 Datasheet(HTML) 4 Page - Linear Technology

   
Zoom Inzoom in Zoom Outzoom out
 4 / 8 page
background image
LT1109
4
I
DAGRA
BLOCK
S
LT1109-5, -12 Z Package
The LT1109Z-5 and LT1109Z-12 are fixed output voltage
step-up DC/DC converters in a 3-pin TO-92 package.
Power for internal regulator circuitry is taken from the
VOUT pin, a technique known as “bootstrapping.” Circuit
operation can be best understood by referring to the block
diagram. VOUT, attenuated by R1 and R2, is applied to the
negative input of comparator A1. When this voltage falls
below the 1.25V reference voltage, the oscillator is turned
on and the power switch Q1 cycles at the oscillator
frequency of 120kHz. Switch cycling alternately builds
current in the inductor, then dumps it into the output
capacitor, increasing the output voltage. When A1’s nega-
tive input rises above 1.25V, it turns off the oscillator. A
small amount of hysteresis in A1 obviates the need for
frequency compensation circuitry. When Q1 is off, current
into the VOUT pin drops to just 320µA. Quiescent current
from the battery will be higher because the device oper-
ates off the
stepped-up voltage.
LT1109-5, -12 N8, S8 Package
CC
HARA TERISTICS
A
TYPICALPERFOR
CE
LT1109Z
ATIO
OPER
Minimum/Maximum
Oscillator Frequency vs tON
Quiescent Current
Quiescent Current
INPUT VOLTAGE (V)
0
200
300
450
20
LT1109 • TPC09
210
400
18
250
4
8
12 14
350
TA = 25°C
616
TEMPERATURE (°C)
–50
200
280
400
100
LT1109 • TPC10
25
360
75
220
–25
0
50
320
240
260
300
340
380
IN
V
LT1109 • TA04
GND
1.25V
REFERENCE
A1
DRIVER
SW
120kHz
OSCILLATOR
COMPARATOR
R2
250k
R1
+
SENSE
SHUTDOWN
Q1
FB
ON FIXED VERSION PIN 8 IS SENSE
ON ADJUSTABLE VERSION PIN 8 IS FB AND R1 AND R2 ARE DISCONNECTED
OUT
V
LT1109 • TA03
GND
1.25V
REFERENCE
A1
DRIVER
SW
120kHz
OSCILLATOR
COMPARATOR
R2
250k
R1
+
Q1
LT1109-5: R1 = 83k
LT1109-12: R1 = 29k
TON (µs)
2.0
80
110
160
6.0
LT1109 • TPC08
2.5
4.0
140
120
5.5
150
90
3.0
3.5
4.5
5.0
130
100
TA = 25°C
0
°C ≤ T
A ≤ 70°C


Html Pages

1  2  3  4  5  6  7  8 


Datasheet Download




Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn