LT1949-1EMS8#TRPBF Linear Technology, LT1949-1EMS8#TRPBF Datasheet

IC DC/DC CONV PWM 1A SWTCH 8MSOP

LT1949-1EMS8#TRPBF

Manufacturer Part Number
LT1949-1EMS8#TRPBF
Description
IC DC/DC CONV PWM 1A SWTCH 8MSOP
Manufacturer
Linear Technology
Type
Step-Up (Boost)r
Datasheet

Specifications of LT1949-1EMS8#TRPBF

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
Adj to 28V
Current - Output
1A
Frequency - Switching
1.1MHz
Voltage - Input
1.7 ~ 12 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LT1949-1EMS8#TRPBFLT1949-1EMS8
Manufacturer:
LT
Quantity:
10 000
Company:
Part Number:
LT1949-1EMS8#TRPBFLT1949-1EMS8#TR
Manufacturer:
LT
Quantity:
1 000
FEATURES
TYPICAL APPLICATIO
APPLICATIO S
1A, 0.5 , 30V Internal Switch
1.1MHz Fixed Frequency Operation
Operates with V
Low-Battery Detector Stays Active in Shutdown
Low V
Pin-for-Pin Compatible with the LT1317B
Uses Ceramic Capacitors
Small 8-Lead MSOP Package
LCD Bias Supplies
GPS Receivers
Battery Backup
Portable Electronic Equipment
Diagnostic Medical Instrumentation
3.3V
V
IN
Figure 1. 3.3V to 10V/175mA DC/DC Converter
C1, C2: TAIYO YUDEN LMK325BJ335MD
D1: MBRM120LT3
L1: SUMIDA CLQ4D10-4R7
CESAT
SHUTDOWN
C1
3.3 F
CERAMIC
Switch: 410mV at 800mA
IN
U
as Low as 1.5V
SHDN
V
V
IN
C
84.5k
LT1949-1
50pF
4.7 H
L1
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 represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
GND
SW
FB
U
R2
28k
1%
D1
196k
1%
R1
3pF
1949-1 F01
C2
3.3 F
CERAMIC
V
10V
175mA
OUT
DESCRIPTIO
The LT
verter with a 1A, 0.5 internal switch. Capable of gener-
ating 10V at 175mA from a 3.3V input, the LT1949-1 is
ideal for generating bias voltages for large screen LCD
panels. Constant frequency 1.1MHz operation results in a
low noise output that is easy to filter and the 30V switch
rating allows output voltage up to 28V using a single
inductor. The high switching frequency allows the use of
ceramic output capacitors. An external compensation pin
gives the user flexibility in optimizing loop compensation,
allowing small, low ESR ceramic capacitors to be used at
the output. The 8-lead MSOP package ensures a low
profile overall solution.
The LT1949-1 includes a low-battery detector that stays
alive when the device goes into shutdown. Quiescent
current in shutdown is 50 A, while operating current is
8mA.
, LTC and LT are registered trademarks of Linear Technology Corporation.
PWM DC/DC Converter
®
1949-1 is a fixed frequency step-up DC/DC con-
Figure 2. 3.3V to 10V Converter Efficiency
90
80
70
60
50
40
30
20
5
V
OUT
1.1MHz, 1A Switch
10
= 10V
U
LOAD CURRENT (mA)
Final Electrical Specifications
3.6V
50
IN
100
4.2V
IN
1949-1 F02
3V
LT1949-1
IN
June 2000
300
1

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LT1949-1EMS8#TRPBF Summary of contents

Page 1

... The LT 1949 fixed frequency step-up DC/DC con- verter with a 1A, 0.5 internal switch. Capable of gener- ating 10V at 175mA from a 3.3V input, the LT1949-1 is ideal for generating bias voltages for large screen LCD panels. Constant frequency 1.1MHz operation results in a low noise output that is easy to filter and the 30V switch rating allows output voltage up to 28V using a single inductor ...

Page 2

... SHDN Input Voltage Low Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT1949-1E is guaranteed to meet performance specifications from Specifications over the – operating temperature range are assured by design, characterization and correlation with statistical process controls. ...

Page 3

... TEMPERATURE ( C) 1949-1 G05 FB Pin Bias Current –50 – 100 TEMPERATURE ( C) 1949-1 G08 LT1949-1 Switch Current Limit, Duty Cycle = 30% 1.3 1.2 1.1 1.0 0.9 0.8 –50 – 100 TEMPERATURE ( C) 1949-1 G03 Quiescent Current, SHDN = 2V 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5 ...

Page 4

... LT1949 TYPICAL PERFOR A CE CHARACTERISTICS AC COUPLED CTIO S V (Pin 1): Compensation Pin for Error Amplifier. Con- C nect a series RC network from this pin to ground. Typical values for compensation are a 30k/330pF combination when using ceramic output capacitors. Minimize trace area (Pin 2): Feedback Pin. Reference voltage is 1.24V. ...

Page 5

... IN oscillation. The ground terminal of output capacitor C2 should tie close to Pin 4 of the LT1949-1. Doing this reduces dI/dt in the ground copper which keeps high frequency spikes to a minimum. The DC/DC converter ground should tie to the PC board ground plane at one place only, to avoid intro- ducing dI/dt in the ground plane ...

Page 6

... U APPLICATIO S I FOR ATIO Low-Battery Detector The LT1949-1’s low-battery detector is a simple PNP input gain stage with an open collector NPN output. The nega- tive input of the gain stage is tied internally to a 200mV 5% reference. The positive input is the LBI pin. Arrange- ment as a low-battery detector is straightforward ...

Page 7

... Plastic MSOP (LTC DWG # 05-08-1660) 0.118 0.004* (3.00 0.102) 0.193 0.006 (4.90 0.15) 0.040 0.006 (1.02 0.15) 0 – 6 TYP SEATING PLANE 0.012 0.021 0.006 (0.30) (0.53 0.015) 0.0256 REF LT1949 OUT 5V 250mA 100k 6.3V 33.2k 1% 1949-1 TA02 0.118 0.004** (3.00 0.102) ...

Page 8

... Low Profile Triple Output LCD Bias Generator 0 4 SHDN R2 LT1949-1 40. GND 30.1k 7.5k C3 330pF COMMENTS 5V/600mA from 2V, 2A Internal Switch, 200 A I Low-Battery Detector Active in Shutdown 3.3V at 75mA from 1 Cell, MSOP Package 36V Switch, Fixed Frequency Operation, SO-8 and TSSOP Packages 2 Cells to 3 ...

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