LTC1872B
Constant Frequency
Current Mode Step-Up
DC/DC Controller in ThinSOT
Fea T Descrip T
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Burst Mode Operation Disabled for Lower Output The LTC 1872B is a constant frequency current mode
Ripple at Light Loads step-up DC/DC controller providing excellent AC and DC
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High Efficiency: Over 90% load and line regulation. The device incorporates an ac-
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High Output Currents Easily Achieved curate undervoltage lockout feature that shuts down the
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Wide V Range: 2.5V to 9.8V LTC1872B when the input voltage falls below 2.0V.
IN
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V Limited Only by External Components
OUT
The LTC1872B provides a 2.5% output voltage accuracy
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Constant Frequency 550kHz Operation
and consumes only 270A of quiescent current. In shut-
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Current Mode Operation for Excellent Line and Load
down, the device draws a mere 8A.
Transient Response
n High constant operating frequency of 550kHz allows the
Shutdown Mode Draws Only 8A Supply Current
n use of a small external inductor. The constant frequency
Low Profile (1mm) ThinSOT Package
operation is maintained down to very light loads, resulting
a T
in less low frequency noise generation over a wide load
current range.
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Optical Communications
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The LTC1872B is available in a 6-lead low profile (1mm)
Lithium-Ion-Powered Applications
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ThinSOT package. For a Burst Mode operation enabled
Cellular Telephones
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version of the LTC1872B, please refer to the LTC1872
Wireless Devices
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data sheet.
Portable Computers
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L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
Scanners
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Typical a T
Typical Efficiency vs Load Current*
V
IN
3.3V
100
C1
R1
V = 3.3V
10F IN
0.03
V = 5V
10V OUT
95
147k
1 5
L1
I /RUN V
TH IN
90
4.7H
LTC1872B
220pF
V
OUT
2 4
85
5V
GND SENSE
C2
80.6k
1A
3 6
D1
V NGATE M1 4 10F
FB
80
10V
422k
75
70
C1: TAIYO YUDEN CERAMIC EMK325BJ106MNT
C2: MURATA GRM42-2X5R106K010AL
D1: IR10BQ015
65
L1: MURATA LQN6C4R7M04
1 10 100 1000
M1: Si2302DS
LOAD CURRENT (mA)
1872B TA01
R1: DALE 0.25W
1872B TA01b
Figure 1. LTC1872B High Output Current 3.3V to 5V Boost Converter
*Output ripple waveforms for the circuit of Figure 1 appear in Figure 2.
1872bfa
1
For more information www.linear.com/LTC1872B
EFFICIENCY (%)
ion pplica
ions pplica
ion uresLTC1872B
a Te Maxi Mu M r a T p in c F T
(Note 1)
Input Supply Voltage (V ) ......................... 0.3V to 10V
TOP VIEW
IN
SENSE , NGATE Voltages ............. 0.3V to (V + 0.3V)
IN
I /RUN 1 6 NGATE
TH
V , I /RUN Voltages .............................. 0.3V to 2.4V
FB TH GND 2 5 V
IN
NGATE Peak Output Current (<10s) ........................ 1A
V 3 4 SENSE
FB
Storage Ambient Temperature Range ....65C to 150C
S6 PACKAGE
6-LEAD PLASTIC SOT-23
Operating Temperature Range (Note 2)....40C to 85C
T = 150C, = 230C/W
JMAX JA
Junction Temperature (Note 3) ............................. 150C
Lead Temperature (Soldering, 10 sec) ...................300C
o r Der i n F Ma T
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC1872BES6#PBF LTC1872BES6#TRPBF LTXY 16-Lead Plastic SOT-23 40C to 85C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: