Electronic Components Datasheet Search
  English  ▼

X  

Preview PDF HTML

LT1302CS8 Datasheet(PDF) 6 Page - Linear Technology

Part # LT1302CS8
Description  Micropower High Output Current Step-Up Adjustable and Fixed 5V DC/DC Converters
PDF  16 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  LINER [Linear Technology]
Direct Link  http://www.linear.com
Logo LINER - Linear Technology

LT1302CS8 Datasheet(HTML) 6 Page - Linear Technology

Back Button LT1302CS8 Datasheet HTML 2Page - Linear Technology LT1302CS8 Datasheet HTML 3Page - Linear Technology LT1302CS8 Datasheet HTML 4Page - Linear Technology LT1302CS8 Datasheet HTML 5Page - Linear Technology LT1302CS8 Datasheet HTML 6Page - Linear Technology LT1302CS8 Datasheet HTML 7Page - Linear Technology LT1302CS8 Datasheet HTML 8Page - Linear Technology LT1302CS8 Datasheet HTML 9Page - Linear Technology LT1302CS8 Datasheet HTML 10Page - Linear Technology Next Button
Zoom Inzoom in Zoom Outzoom out
 6 / 16 page
background image
6
LT1302/LT1302-5
BLOCK DIAGRA SM
The LT1302’s operation can best be understood by
examining the block diagram in Figure 2. The LT1302
operates in one of two modes, depending on load. With
light loads, comparator CMP1 controls the output; with
heavy loads, control is passed to error amplifier A1.
Burst Mode operation consists of monitoring the FB pin
voltage with hysteretic comparator CMP1. When the FB
voltage, related to the output voltage by external attenu-
ator R1 and R2, falls below the 1.24V reference voltage,
the oscillator is enabled. Switch Q4 alternately turns on,
causing current buildup in inductor L1, then turns off,
allowing the built-up current to flow into output capaci-
tor C3 via D1. As the output voltage increases, so does
the FB voltage; when it exceeds the reference plus
OPERATIO
CMP1’s hysteresis (about 5mV) CMP1 turns the oscilla-
tor off. In this mode, peak switch current is limited to
approximately 1A by A2, Q2, and Q3. Q2’s current, set at
34
µA, flows through R5, causing A2’s negative input to
be 25mV lower than VIN. This node must fall more than
36mV below VIN for A2 to trip and turn off the oscillator.
The remaining 11mV is generated by Q3’s current flow-
ing through R4. Emitter-area scaling sets Q3’s collector
current to 0.625% of switch Q4’s current. When Q4’s
current is 1A, Q3’s current is 6.25mA, creating an 11mV
drop across R4 which, added to R5’s 25mV drop, is
enough to trip A2.
When the output load is increased to the point where the
1A peak current cannot support the output voltage,
1302 F03
–
+
–
+
–
+
VOS
15mV
36mV
CMP1
OFF
VIN
2
µA
ENABLE
A2
VIN
SW
PGND
IT
VC
GND
SHDN
SHUTDOWN
SENSE
ERROR
AMPLIFIER
HYSTERETIC
COMPARATOR
DRIVER
A1
4
3
5
8
7
2
1
1.24V
REFERENCE
220kHz
OSCILLATOR
300
Ω
3.6k
Q3
R4
1.75
Ω
R5
730
Ω
VIN
BIAS
R1
315k
R2
105k
6
Q4
160X
A3
Q1
Q2
Q5
Figure 3. LT1302-5 Block Diagram



Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16


Datasheet Download

Go To PDF Page


Link URL



Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link to Datasheet    |   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
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com