LTC1775C 반도체 회로 부품 판매점
High Power No RSENSE TM Current Mode Synchronous Step-Down Switching Regulator
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 Linear Technology |
FEATURES
s Highest Efficiency Current Mode Controller
s No Sense Resistor Required
s 300mV Maximum Current Sense Voltage
s Stable High Current Operation
s Dual N-Channel MOSFET Synchronous Drive
s Wide VIN Range: 4V to 36V
s Wide VOUT Range: 1.19V to VIN
s ±1% 1.19V Reference
s Programmable Fixed Frequency with Injection Lock
s Very Low Drop Out Operation: 99% Duty Cycle
s Forced Continuous Mode Control Pin
s Optional Programmable Soft Start
s Pin Selectable Output Voltage
s Foldback Current Limit
s Output Overvoltage Protection
s Logic Controlled Micropower Shutdown: IQ < 30µA
s Available in 16-Lead Narrow SSOP and SO Packages
U
APPLICATIO S
s Notebook Computers
s Automotive Electronics
s Battery Chargers
s Distributed Power Systems
LTC1775
High Power
No RSENSETM Current Mode
Synchronous Step-Down
Switching Regulator
DESCRIPTIO
The LTC®1775 is a synchronous step-down switching
regulator controller that drives external N-channel power
MOSFETs using few external components. Current mode
control with MOSFET VDS sensing eliminates the need for
a sense resistor and improves efficiency. Largely similar
to the LTC1625, the LTC1775 has twice the maximum
sense voltage for high current applications. The frequency
of a nominal 150kHz internal oscillator can be synchro-
nized to an external clock over a 1.5:1 frequency range.
Burst ModeTM operation at low load currents reduces
switching losses and low dropout operation extends oper-
ating time in battery-powered systems. A forced continu-
ous mode control pin can assist secondary winding
regulation by disabling Burst Mode operation when the
main output is lightly loaded.
Fault protection is provided by foldback current limiting
and an output overvoltage comparator. An external ca-
pacitor attached to the RUN/SS pin provides soft start
capability for supply sequencing. A wide supply range
allows operation from 4V (4.3V for LTC1775I) to 36V at the
input and 1.19V to VIN at the output.
, LTC and LT are registered trademarks of Linear Technology Corporation.
No RSENSE and Burst Mode are trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
CC
2.2nF
CSS 0.1µF
LTC1775
SYNC
VIN
TK
RUN/SS TG
VPROG
SW
BOOST
RC
10k
ITH INTVCC
SGND
BG +
VOSENSE PGND
CB 0.33µF
DB
CMDSH-3
CVCC
4.7µF
+
M1
SUD50N03-10 L1
6µH
D1
MBRS340
M2
SUD50N03-10
CIN
22µF
VIN
5V TO
28V
30V
×4
VOUT
3.3V
+ COUT 10A
680µF
6.3V
1775 F01
Figure 1. High Efficiency Step-Down Converter
Efficiency vs Load Current
100
VIN = 10V
f = 150kHz
95 FCB = INTVCC
VOUT = 5V
90 VOUT = 3.3V
85
80
75
70
0.01
0.1 1
LOAD CURRENT (A)
10
1775 F01b
1
LTC1775
ABSOLUTE AXI U RATI GS
(Note 1)
Input Supply Voltage (VIN, TK) ................. 36V to – 0.3V
Boosted Supply Voltage (BOOST) ............. 42V to – 0.3V
Boosted Driver Voltage (BOOST – SW) ...... 7V to – 0.3V
Switch Voltage (SW) ....................................36V to – 5V
EXTVCC Voltage ...........................................7V to – 0.3V
ITH Voltage ................................................2.7V to – 0.3V
FCB, RUN/SS, SYNC Voltages .....................7V to – 0.3V
VOSENSE, VPROG Voltages ........(INTVCC + 0.3V) to – 0.3V
Peak Driver Output Current < 10µs (TG, BG) ............ 2A
INTVCC Output Current ........................................ 50mA
Operating Ambient Temperature Range
LTC1775C .............................................. 0°C to 70°C
LTC1775I (Note 5) .............................. – 40°C to 85°C
Junction Temperature (Note 2) ............................. 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
EXTVCC 1
SYNC 2
RUN/SS 3
FCB 4
ITH 5
SGND 6
VOSENSE 7
VPROG 8
16 VIN
15 TK
14 SW
13 TG
12 BOOST
11 INTVCC
10 BG
9 PGND
GN PACKAGE
16-LEAD NARROW
PLASTIC SSOP
S PACKAGE
16-LEAD PLASTIC SO
TJMAX = 125°C, θJA = 130°C/W (GN)
TJMAX = 125°C, θJA = 110°C/W (S)
ORDER PART
NUMBER
LTC1775CGN
LTC1775CS
LTC1775IGN
LTC1775IS
GN PART MARKING
1775
1775I
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS The q denotes specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VIN = 15V unless otherwise noted.
SYMBOL
PARAMETER
Main Control Loop
IINVOSENSE
VOUT
Feedback Current
Regulated Output Voltage
1.19V (Adjustable) Selected
3.3V Selected
5V Selected
VLINEREG
Reference Voltage Line Regulation
VLOADREG
Output Voltage Load Regulation
VFCB
IFCB
VOVL
IPROG
IQ
Forced Continuous Threshold
Forced Continuous Bias Current
Output Overvoltage Lockout
VPROG Input Current
3.3V VOUT
5V VOUT
Input DC Supply Current
Normal Mode
Shutdown
VRUN/SS
IRUN/SS
∆VSENSE(MAX)
RUN/SS Pin Threshold
Soft Start Current Source
Maximum Current Sense Threshold
CONDITIONS
VPROG Pin Open, ITH = 1.19V (Note 3)
ITH = 1.19V (Note 3)
VPROG Pin Open
VPROG = 0V
VPROG = INTVCC
VIN = 4V to 20V, ITH = 1.19V (Note 3),
VPROG Pin Open
ITH = 2V (Note 3)
ITH = 0.5V (Note 3)
VFCB Ramping Negative
VFCB = 1.19V
VPROG Pin Open
VPROG = 0V
VPROG = 5V
EXTVCC = 5V (Note 4)
VRUN/SS = 0V, 4V < VIN < 15V
VRUN/SS = 0V
VOSENSE = 1V, VPROG Pin Open
MIN TYP MAX
10 50
q 1.178
q 3.220
q 4.900
1.190
3.300
5.000
0.001
1.202
3.380
5.100
0.01
q
q
q 1.16
1.24
– 0.020
0.035
1.19
–1
1.28
– 0.2
0.2
1.22
–2
1.32
– 3.5 – 7
3.5 7
q 0.8
–1.2
260
500
15 30
1.4 2
–2.5 –4
300 340
UNITS
nA
V
V
V
%/V
%
%
V
µA
V
µA
µA
µA
µA
V
µA
mV
2
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( linear )
LTC1775C regulator
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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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전력반도체 문의 : 010-3582-2743
관련 데이터시트
LTC1775
High Power No RSENSE TM Current Mode Synchronous Step-Down Switching Regulator - Linear Technology
LTC1775C
High Power No RSENSE TM Current Mode Synchronous Step-Down Switching Regulator - Linear Technology
LTC1775CGN
High Power No RSENSE TM Current Mode Synchronous Step-Down Switching Regulator - Linear Technology
LTC1775CS
High Power No RSENSE TM Current Mode Synchronous Step-Down Switching Regulator - Linear Technology
LTC1775I
High Power No RSENSE TM Current Mode Synchronous Step-Down Switching Regulator - Linear Technology
LTC1775IGN
High Power No RSENSE TM Current Mode Synchronous Step-Down Switching Regulator - Linear Technology
LTC1775IS
High Power No RSENSE TM Current Mode Synchronous Step-Down Switching Regulator - Linear Technology