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LTC1871EMS-7#TRPBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33P34-P34
LTC1871-7
1
18717fd
Typical applicaTion
FeaTures
applicaTions
DescripTion
High Input Voltage,
Current Mode Boost,
Flyback and SEPIC Controller
The LTC
®
1871-7 is a current mode, boost, flyback and
SEPIC controller optimized for driving 6V-rated MOSFETs
in high voltage applications. The LTC1871-7 works equally
well in low or high power applications and requires few
components to provide a complete power supply solution.
The switching frequency can be set with an external resistor
over a 50kHz to 1MHz range, and can be synchronized to
an external clock using the MODE/SYNC pin. Burst Mode
operation at light loads, a low minimum operating supply
voltage of 6V and a low shutdown quiescent current of
10µA make the LTC1871-7 well suited for battery-operated
systems. For applications requiring constant frequency
operation, Burst Mode operation can be defeated using
the MODE/SYNC pin. The LTC1871-7 is available in the
10-lead MSOP package.
PARAMETER LTC1871-7 LTC1871
INTV
CC
7.0V 5.2V
INTV
CC
UV
+
5.6V 2.1V
INTV
CC
UV
–
4.6V 1.9V
Figure 1. Small, Nonisolated 12V Flyback Telecom Housekeeping Supply
n
Optimized for High Input Voltage Applications
n
Wide Chip Supply Voltage Range: 6V to 36V
n
Internal 7V Low Dropout Voltage Regulator
Optimized for 6V-Rated MOSFETs
n
Current Mode Control Provides Excellent
Transient Response
n
High Maximum Duty Cycle (92% Typ)
n
±2% RUN Pin Threshold with 100mV Hysteresis
n
±1% Internal Voltage Reference
n
Micropower Shutdown: I
Q
= 10µA
n
Programmable Operating Frequency
(50kHz to 1MHz) with One External Resistor
n
Synchronizable to an External Clock Up to 1.3 × f
OSC
n
User-Controlled Pulse Skip or Burst Mode
®
Operation
n
Output Overvoltage Protection
n
Can be Used in a No R
SENSE
™ Mode for V
DS
< 36V
n
Small 10-Lead MSOP Package
n
Telecom Power Supplies
n
42V Automotive Systems
n
24V Industrial Controls
n
IP Phone Power Supplies
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. No R
SENSE
is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
RUN
I
TH
FB
FREQ
MODE/SYNC
SENSE
V
IN
INTV
CC
GATE
GND
LTC1871-7
120k
4.7µF
X5R
2.2µF
100V
X7R
M1
FDC2512
0.12Ω
V
IN
36V TO 72V
3.4k
2.2nF
26.7k
D3
10BQ060
47µF
16V
X5R
V
OUT
12V
0.4A
604k
12.4k
T1
VP1-0076
100k
10Ω
Q1
FMMT625
D2
4148
D1
9.1V
110k
0.1µF
X5R
3:1
18717 F01
•
•
LTC1871-7
2
18717fd
pin conFiguraTionabsoluTe MaxiMuM raTings
V
IN
Voltage ............................................... – 0.3V to 36V
INTV
CC
Voltage ........................................... –0.3V to 9V
INTV
CC
Output Current...........................................50mA
GATE Voltage ........................... –0.3V to V
INTVCC
+ 0.3V
I
TH
, FB Voltages ....................................... –0.3V to 2.7V
RUN Voltage................................................ –0.3V to 7V
MODE/SYNC Voltage ................................... –0.3V to 9V
FREQ Voltage ............................................ –0.3V to 1.5V
SENSE Pin Voltage .................................... –0.3V to 36V
Operating Temperature Range (Note 2)
LTC1871E-7 ..........................................–40°C to 85°C
LTC1871I-7 ......................................... –40°C to 125°C
Junction Temperature (Note 3) ............................. 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec) ................... 300°C
(Note 1)
1
2
3
4
5
RUN
I
TH
FB
FREQ
MODE/
SYNC
10
9
8
7
6
SENSE
V
IN
INTV
CC
GATE
GND
TOP VIEW
MS PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 125°C, θ
JA
= 120°C/W
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC1871EMS-7#PBF LTC1871EMS-7#TRPBF LTG4 10-Lead Plastic MSOP –40°C to 85°C
LTC1871IMS-7#PBF LTC1871IMS-7#TRPBF LTBTR 10-Lead Plastic MSOP –40°C to 125°C
LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC1871EMS-7 LTC1871EMS-7#TR LTG4 10-Lead Plastic MSOP –40°C to 85°C
LTC1871IMS-7 LTC1871IMS-7#TR LTBTR 10-Lead Plastic MSOP –40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loop
V
IN(MIN)
Minimum Input Voltage 6 V
I-Grade (Note 2)
●
6 V
I
Q
Input Voltage Supply Current (Note 4)
Continuous Mode V
MODE/SYNC
= 5V, V
FB
= 1.4V, V
ITH
= 0.75V 550 1000 µA
V
MODE/SYNC
= 5V, V
FB
= 1.4V, V
ITH
= 0.75V,
I-Grade (Note 2)
●
600 1100 µA
Burst Mode Operation, No Load V
MODE/SYNC
= 0V, V
ITH
= 0.2V (Note 5) 280 500 µA
V
MODE/SYNC
= 0V, V
ITH
= 0.2V (Note 5),
I-Grade (Note 2)
●
280 600 µA
Shutdown Mode V
RUN
= 0V 12 25 µA
V
RUN
= 0V, I-Grade (Note 2)
●
12 25 µA
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 8V, V
RUN
= 1.5V, R
FREQ
= 80k, V
MODE/SYNC
= 0V, unless otherwise specified.
LTC1871-7
3
18717fd
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 8V, V
RUN
= 1.5V, R
FREQ
= 80k, V
MODE/SYNC
= 0V, unless otherwise specified.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
RUN
+
Rising RUN Input Threshold Voltage 1.348 V
V
RUN
–
Falling RUN Input Threshold Voltage
●
1.223
1.198
1.248 1.273
1.298
V
V
V
RUN(HYST)
RUN Pin Input Threshold Hysteresis 50 100 150 mV
I-Grade (Note 2)
●
35 100 175 mV
I
RUN
RUN Input Current 5 60 nA
V
FB
Feedback Voltage V
ITH
= 0.2V (Note 5)
●
1.218
1.212
1.230 1.242
1.248
V
V
V
ITH
= 0.2V (Note 5), I-Grade (Note 2)
●
1.205 1.255 V
I
FB
FB Pin Input Current V
ITH
= 0.2V (Note 5) 18 60 nA
∆V
FB
∆V
IN
Line Regulation 6V ≤ V
IN
≤ 30V 0.002 0.02 %/V
6V ≤ V
IN
≤ 30V, I-Grade (Note 2)
●
0.002 0.02 %/V
∆V
FB
∆V
ITH
Load Regulation V
MODE/SYNC
= 0V, V
ITH
= 0.5V to 0.9V (Note 5)
●
–1 –0.1 %
V
MODE/SYNC
= 0V, V
ITH
= 0.5V to 0.9V (Note 5)
I-Grade (Note 2)
●
–1 –0.1 %
∆V
FB(OV)
∆FB Pin, Overvoltage Lockout
V
FB(OV)
– V
FB(NOM)
in Percent 2.5 6 10 %
g
m
Error Amplifier Transconductance I
TH
Pin Load = ±5µA (Note 5) 600 µmho
V
ITH(BURST)
Burst Mode Operation I
TH
Pin Voltage Falling I
TH
Voltage (Note 5) 0.3 V
V
SENSE(MAX)
Maximum Current Sense Input Threshold Duty Cycle < 20% 120 150 180 mV
Duty Cycle < 20%, I-Grade (Note 2)
●
100 200 mV
I
SENSE(ON)
SENSE Pin Current (GATE High) V
SENSE
= 0V 35 70 µA
I
SENSE(OFF)
SENSE Pin Current (GATE Low) V
SENSE
= 30V 0.1 5 µA
Oscillator
f
OSC
Oscillator Frequency R
FREQ
= 80k 250 300 350 kHz
R
FREQ
= 80k, I-Grade (Note 2)
●
250 300 350 kHz
Oscillator Frequency Range 50 1000 kHz
I-Grade (Note 2)
●
50 1000 kHz
D
MAX
Maximum Duty Cycle 87 92 97 %
I-Grade (Note 2)
●
87 92 98.5 %
f
SYNC/
f
OSC
Recommended Maximum Synchronized
Frequency Ratio
f
OSC
= 300kHz (Note 6) 1.25 1.30
f
OSC
= 300kHz (Note 6), I-Grade (Note 2)
●
1.25 1.30
t
SYNC(MIN)
MODE/SYNC Minimum Input Pulse Width V
SYNC
= 0V to 5V 25 ns
t
SYNC(MAX)
MODE/SYNC Maximum Input Pulse Width V
SYNC
= 0V to 5V 0.8/f
OSC
ns
V
IL(MODE)
Low Level MODE/SYNC Input Voltage 0.3 V
I-Grade (Note 2)
●
0.3 V
V
IH(MODE)
High Level MODE/SYNC Input Voltage 1.2 V
I-Grade (Note 2)
●
1.2 V
R
MODE/SYNC
MODE/SYNC Input Pull-Down Resistance 50 kΩ
V
FREQ
Nominal FREQ Pin Voltage 0.62 V
Low Dropout Regulator
V
INTVCC
INTV
CC
Regulator Output Voltage V
IN
= 8V 6.5 7 7.5 V
V
IN
= 8V, I-Grade (Note 2)
●
6.5 7 7.5 V
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LTC1871EMS-7#TRPBF

Mfr. #:
Buy LTC1871EMS-7#TRPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Controllers No Rsense DC/DC Controller Boost, Flyback & SEPIC
Lifecycle:
New from this manufacturer.
Delivery:
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