LTC1871 반도체 회로 부품 판매점
Wide Input Range/ No RSENSE Current Mode Boost/ Flyback and SEPIC Controller
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 Linear Technology |
LTC1871
Wide Input Range, No RSENSETM
Current Mode Boost, Flyback and SEPIC Controller
FEATURES
s High Efficiency (No Sense Resistor Required)
s Wide Input Voltage Range: 2.5V to 36V
s Current Mode Control Provides Excellent
Transient Response
s High Maximum Duty Cycle (92% Typ)
s ±2% RUN Pin Threshold with 100mV Hysteresis
s ±1% Internal Voltage Reference
s Micropower Shutdown: IQ = 10µA
s Programmable Operating Frequency
(50kHz to 1MHz) with One External Resistor
s Synchronizable to an External Clock Up to 1.3 × fOSC
s User-Controlled Pulse Skip or Burst Mode® Operation
s Internal 5.2V Low Dropout Voltage Regulator
s Output Overvoltage Protection
s Capable of Operating with a Sense Resistor for High
Output Voltage Applications
s Small 10-Lead MSOP Package
U
APPLICATIO S
s Telecom Power Supplies
s Portable Electronic Equipment
DESCRIPTIO
The LTC®1871 is a wide input range, current mode, boost,
flyback and SEPIC controller that drives an N-channel
power MOSFET and requires very few external compo-
nents. Intended for low to medium power applications, it
eliminates the need for a current sense resistor by utiliz-
ing the power MOSFET’s on-resistance, thereby maximiz-
ing efficiency.
The IC’s operating frequency can be set with an external
resistor over a 50kHz to 1MHz range, and can be synchro-
nized to an external clock using the MODE/SYNC pin.
Burst Mode operation at light loads, a low minimum
operating supply voltage of 2.5V and a low shutdown
quiescent current of 10µA make the LTC1871 ideally
suited for battery-operated systems.
For applications requiring constant frequency operation,
Burst Mode operation can be defeated using the MODE/
SYNC pin. Higher output voltage boost, SEPIC and fly-
back applications are possible with the LTC1871 by
connecting the SENSE pin to a resistor in the source of the
power MOSFET.
The LTC1871 is available in the 10-lead MSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation.
No RSENSE is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
L1
1µH
D1
VIN
3.3V
RC
22k
CC1
6.8nF
CC2
47pF
R2
37.4k
1%
R1
12.1k
1%
RT
80.6k
1%
RUN SENSE
ITH VIN
LTC1871
FB
FREQ
INTVCC
GATE
MODE/SYNC GND
CVCC +
4.7µF
X5R
CIN
22µF
6.3V
×2
M1
CIN: TAIYO YUDEN JMK325BJ226MM
COUT1: PANASONIC EEFUEOJ151R
COUT2: TAIYO YUDEN JMK325BJ226MM
D1: MBRB2515L
L1: SUMIDA CEP125-H 1R0MH
M1: FAIRCHILD FDS7760A
VOUT
5V
+ COUT1
150µF
7A
(10A PEAK)
6.3V
×4 COUT2
22µF
6.3V
X5R
×2
GND
1871 F01a
Figure 1. High Efficiency 3.3V Input, 5V Output Boost Converter (Bootstrapped)
Efficiency of Figure 1
100
90
Burst Mode
80 OPERATION
70
PULSE-SKIP
60 MODE
50
40
30
0.001
0.01 0.1
1
OUTPUT CURRENT (A)
10
1871 F01b
1
LTC1871
ABSOLUTE AXI U RATI GS
(Note 1)
VIN Voltage ............................................... – 0.3V to 36V
INTVCC Voltage ........................................... – 0.3V to 7V
INTVCC Output Current ........................................ 50mA
GATE Voltage ........................... – 0.3V to VINTVCC + 0.3V
ITH, FB Voltages ....................................... – 0.3V to 2.7V
RUN, MODE/SYNC Voltages ....................... – 0.3V to 7V
FREQ Voltage ............................................– 0.3V to 1.5V
SENSE Pin Voltage ................................... – 0.3V to 36V
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Junction Temperature (Note 3) ............................ 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
RUN 1
10 SENSE
ITH 2
FB 3
FREQ 4
9 VIN
8 INTVCC
7 GATE
MODE/ 5
6 GND
SYNC
MS PACKAGE
10-LEAD PLASTIC MSOP
TJMAX = 125°C, θJA = 120°C/ W
ORDER PART
NUMBER
LTC1871EMS
MS PART MARKING
LTSX
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
VIN = VINTVCC = 5V, VRUN = 1.5V, RFREQ = 80k, VMODE/SYNC = 0V, unless otherwise specified.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Main Control Loop
VIN(MIN)
IQ
VRUN+
VRUN–
Minimum Input Voltage
Input Voltage Supply Current
Continuous Mode
Burst Mode Operation, No Load
Shutdown Mode
Rising RUN Input Threshold Voltage
Falling RUN Input Threshold Voltage
(Note 4)
VMODE/SYNC = 5V, VFB = 1.4V, VITH = 0.75V
VMODE/SYNC = 0V, VITH = 0.2V (Note 5)
VRUN = 0V
2.5
1.223
q 1.198
550
250
10
1.348
1.248
1000
500
20
1.273
1.298
V
µA
µA
µA
V
V
V
VRUN(HYST)
IRUN
VFB
RUN Pin Input Threshold Hysteresis
RUN Input Current
Feedback Voltage
VITH = 0.2V (Note 5)
50
1.218
q 1.212
100
1
1.230
150
60
1.242
1.248
mV
nA
V
V
IFB
∆VFB
∆VIN
∆VFB
∆VITH
∆VFB(OV)
gm
VITH(BURST)
VSENSE(MAX)
ISENSE(ON)
ISENSE(OFF)
FB Pin Input Current
Line Regulation
Load Regulation
∆FB Pin, Overvoltage Lockout
Error Amplifier Transconductance
Burst Mode Operation ITH Pin Voltage
Maximum Current Sense Input Threshold
SENSE Pin Current (GATE High)
SENSE Pin Current (GATE Low)
VITH = 0.2V (Note 5)
2.5V ≤ VIN ≤ 30V
VMODE/SYNC = 0V, VTH = 0.5V to 0.90V (Note 5) q
VFB(OV) – VFB(NOM) in Percent
ITH Pin Load = ±5µA (Note 5)
Falling ITH Voltage (Note 5)
Duty Cycle < 20%
VSENSE = 0V
VSENSE = 30V
–1
2.5
120
18
0.002
60
0.02
– 0.1
6 10
650
0.3
150 180
35 50
0.1 5
nA
%/V
%
%
µmho
V
mV
µA
µA
2
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제조업체: Linear Technology
( linear )
LTC1871 controller
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국내 전력반도체 판매점
상호 : 아이지 인터내셔날
전화번호 : 051-319-2877
[ 홈페이지 ]
IGBT, TR 모듈, SCR, 다이오드모듈, 각종 전력 휴즈
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