LT1111CN8-12 Linear Technology, LT1111CN8-12 Datasheet

IC DC/DC CONV FIXED OUT 12V 8DIP

LT1111CN8-12

Manufacturer Part Number
LT1111CN8-12
Description
IC DC/DC CONV FIXED OUT 12V 8DIP
Manufacturer
Linear Technology
Type
Step-Down (Buck), Step-Up (Boost), Invertingr
Datasheet

Specifications of LT1111CN8-12

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
12V
Current - Output
400mA
Frequency - Switching
72kHz
Voltage - Input
2 ~ 30 V
Operating Temperature
0°C ~ 70°C
Mounting Type
Through Hole
Package / Case
8-DIP (0.300", 7.62mm)
Power - Output
500mW
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LT1111CN8-12
Manufacturer:
MOT
Quantity:
1 825
3V INPUT
FEATURES
APPLICATIO S
TYPICAL APPLICATIO
Operates at Supply Voltages from 2V to 30V
Works with Surface Mount Inductors
72kHz Oscillator
Only Three External Components Required
Step-Up or Step-Down Mode
Low-Battery Detector Comparator On-Chip
User Adjustable Current Limit
Internal 1A Power Switch
Fixed or Adjustable Output Voltage Versions
Space Saving 8-Pin MiniDIP or SO-8 Package
3V to 5V, 5V to 12V Converters
9V to 5V, 12V to 5V Converters
Remote Controls
Peripherals and Add-On Cards
Battery Backup Supplies
Uninterruptible Supplies
Laptop and Palmtop Computers
Cellular Telephones
Portable Instruments
Flash Memory VPP Generators
+
*OPTIONAL
All Surface Mount 3V to 5V Step-Up Converter
10 F*
I
GND
LT1111CS8-5
LIM
U
V
SW2
SENSE
IN
SW1
CD54-220M
SUMIDA
22 H
U
MBRS120T3
+
LT1111 • TA01
33 F
5V
100mA
Adjustable and Fixed 5V, 12V
The LT
The device requires only three external components to
deliver a fixed output of 5V or 12V. Supply voltage ranges
from 2V to 12V in step-up mode and to 30V in step-down
mode. The LT1111 functions equally well in step-up, step-
down, or inverting applications.
The LT1111 oscillator is set at 72kHz, optimizing the
device to work with off-the-shelf surface mount inductors.
The device can deliver 5V at 100mA from a 3V input in
step-up mode or 5V at 200mA from a 12V input in step-
down mode.
Switch current limit can be programmed with a single
resistor. An auxiliary open-collector gain block can be
configured as a low-battery detector, linear post regulator,
undervoltage lock-out circuit, or error amplifier.
For input sources of less than 2V use the LT1110.
DESCRIPTIO
, LTC and LT are registered trademarks of Linear Technology Corporation
®
1111 is a versatile micropower DC/DC converter.
6
5
4
3
2
1
0
0
25
Typical Load Regulation
DC/DC Converter
V
IN
U
50
= 2V 2.2 2.4
LOAD CURRENT (mA)
75
100
Micropower
125
2.6
150
LT1111 • TA02
2.8 3V
175
200
LT11 11
1111fd
1

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LT1111CN8-12 Summary of contents

Page 1

... Switch current limit can be programmed with a single resistor. An auxiliary open-collector gain block can be configured as a low-battery detector, linear post regulator, undervoltage lock-out circuit, or error amplifier. For input sources of less than 2V use the LT1110. , LTC and LT are registered trademarks of Linear Technology Corporation MBRS120T3 5V 100mA + 33 F LT1111 • ...

Page 2

... Operating Temperature Range LT1111C ............................................... LT1111I ......................................... – 105 C IN LT1111M (OBSOLETE) ............. – 125 C Storage Temperature Range ................ – 150 C Lead Temperature (Soldering, 10 sec)................. 300 ORDER PART NUMBER TOP VIEW LT1111CN8 LT1111CN8 LIM LT1111CN8- SW1 3 SW2 4 S8 PACKAGE 8-LEAD PLASTIC SO *FIXED VERSION LT1111MJ8 LT1111MJ8-5 JMAX LT1111MJ8-12 ...

Page 3

ELECTRICAL C HARA TERISTICS C temperature range, otherwise specifications are at T SYMBOL PARAMETER I Feedback Pin Bias Current FB I Set Pin Bias Current SET V Gain Block Output Low OL Reference Line Regulation A Gain Block Gain V ...

Page 4

LT1111 W U TYPICAL PERFOR A Oscillator Frequency 100 –50 – 100 TEMPERATURE ( C) LT1111 • TPC01 Duty Cycle ...

Page 5

W U TYPICAL PERFOR A Quiescent Current 400 380 360 340 320 300 280 260 240 220 200 INPUT VOLTAGE (V) LT1111 • TPC10 Set Pin Bias Current 100 ...

Page 6

LT1111 AGRA S BLOCK LT1111 + SET A2 A0 – GAIN BLOCK/ ERROR AMP + 1.25V REFERENCE OSCILLATOR A1 – COMPARATOR GND FB U OPERATIO The LT1111 is a gated oscillator switcher. This type architecture ...

Page 7

PPLICATI S I FOR ATIO A Inductor Selection — General A DC/DC converter operates by storing energy as mag- netic flux in an inductor core, and then switching this energy into the load. Since it is flux, ...

Page 8

LT1111 PPLICATI S I FOR ATIO A Picking an inductor value with 0.2 DCR results in a peak switch current of: – • ...

Page 9

PPLICATI S I FOR ATIO switch closes, current in the inductor builds according to – – where R = 0.65 + DCR ...

Page 10

LT1111 PPLICATI S I FOR ATIO Diode Selection Speed, forward drop, and leakage current are the three main considerations in selecting a catch diode for LT1111 converters. General purpose rectifiers such as the 1N4001 are unsuitable ...

Page 11

PPLICATI S I FOR ATIO When the switch turns off, the SW2 pin falls rapidly and actually goes below ground. D1 turns on when SW2 reaches 0.4V below ground. D1 MUST BE A SCHOTTKY DIODE . ...

Page 12

LT1111 PPLICATI S I FOR ATIO LIM IN SW1 + LT1111 GND SW2 R2 –V IN Figure 8. Negative-to-Positive Converter Using the I Pin LIM The LT1111 switch can be ...

Page 13

PPLICATI S I FOR ATIO Using the Gain Block The gain block (GB) on the LT1111 can be used as an error amplifier, low-battery detector or linear post regulator. The gain block itself is a very ...

Page 14

LT1111 O TYPICAL A PPLICATI 2 1.5V CELLS * L1 = SUMIDA CD54-270K FOR 5V INPUT CHANGE CONVERTER WILL DELIVER –22V AT 40mA Step-Down Converter 100 LIM SW1 9V LT1111-5 ...

Page 15

... FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...

Page 16

... OUT 65V/75V 6mA <100 A, Can be Used for OUT 28V A/1mA 28V 100 A/4.8mA A/28 A OUT 35V/42V 4.5mA <12 A, Can be Used for OUT 35V/42V 4mA <12 A, Can be Used for OUT Q SD LT/TP 0103 1K REV D • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1994 1111fd ...

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