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LTC3835EUFD#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30
LTC3835
1
3835fe
For more information www.linear.com/LTC3835
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
Low I
Q
Synchronous
Step-Down Controller
The LT C
®
3835 is a high performance step-down switching
regulator controller that drives an all N-channel synchro-
nous power MOSFET stage. A constant-frequency current
mode architecture allows a phase-lockable frequency of
up to 650kHz.
The 80µA no-load quiescent current extends operating
life in battery powered systems. OPTI-LOOP compensa-
tion allows the transient
response to be optimized over
a wide range of output capacitance and ESR values. The
LTC3835 features a precision 0.8V reference and a power
good output indicator. The 4V to 36V input supply range
encompasses a wide range of battery chemistries.
The TRACK/SS pin ramps the output voltage during start-
up. Current foldback limits MOSFET heat dissipation during
short-circuit conditions.
High Efficiency Synchronous Step-Down Converter
n
Wide Output Voltage Range: 0.8V ≤ V
OUT
≤ 10V
n
Low Operating Quiescent Current: 80µA
n
OPTI-LOOP
®
Compensation Minimizes C
OUT
n
±1% Output Voltage Accuracy
n
Wide V
IN
Range: 4V to 36V Operation
n
Phase-Lockable Fixed Frequency 140kHz to 650kHz
n
Dual N-Channel MOSFET Synchronous Drive
n
Very Low Dropout Operation: 99% Duty Cycle
n
Adjustable Output Voltage Soft-Start or Tracking
n
Output Current Foldback Limiting
n
Power Good Output Voltage Monitor
n
Clock Output for PolyPhase
®
Applications
n
Output Overvoltage Protection
n
Low Shutdown I
Q
: 10µA
n
Internal LDO Powers Gate Drive from V
IN
or V
OUT
n
Selectable Continuous, Pulse-Skipping or
Burst Mode
®
Operation at Light Loads
n
Small 20-Lead TSSOP or 4mm × 5mm QFN Package
n
Automotive Systems
n
Telecom Systems
n
Battery-Operated Digital Devices
n
Distributed DC Power Systems
L, LT , LT C , LT M , Burst Mode, PolyPhase, OPTI-LOOP, Linear Technology and the Linear logo
are registered trademarks and No R
SENSE
is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents
including 5408150, 5481178, 5705919, 5929620, 6304066, 6498466, 6580258, 6611131.
Comparison of LTC3835 and LTC3835-1
PART #
CLKOUT/
PHASMD
EXTV
CC
PGOOD
PACKAGES
LTC3835 YES YES YES FE20/4 × 5 QFN
LTC3835-1 NO NO NO GN16/3 × 5 DFN
V
OUT
3.3V
5A
150µF
0.01µF
V
IN
4V TO
36V
I
TH
SGND
PLLIN/MODE
V
FB
SENSE
+
SENSE
–
CLKOUT
PLLLPF
RUN
PGOOD
TRACK/SS
INTV
CC
EXTV
CC
BG
PGND
LTC3835
3.3µH
0.012Ω
20k
3835 TA01
100pF
330pF
33k
62.5k
4.7µF
0.22µF
TG
V
IN
BOOST
SW
10µF
LOAD CURRENT (mA)
EFFICIENCY (%)
POWER LOSS (mW)
0.01 0.1 1 10 100 1000 10000
3835 TA01b
0.001
1
10
1000
100
0.1
100000
10000
40
50
60
70
80
30
20
10
0
90
100
POWER LOSS
EFFICIENCY
V
IN
= 12V; V
OUT
= 3.3V
Efficiency and Power Loss
vs Load Current
LTC3835
2
3835fe
For more information www.linear.com/LTC3835
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage (V
IN
) ......................... 36V to –0.3V
Top Side Driver Voltage (BOOST)
............... 42V to –0.3V
Switch Voltage (SW)
..................................... 36V to –5V
INTV
CC
, (BOOST-SW), CLKOUT, PGOOD .. 8.5V to –0.3V
RUN, TRACK/SS
........................................ 7V to –0.3V
SENSE
+
, SENSE
–
Voltages .........................11V to –0.3V
PLLIN/MODE, PHASMD, PLLLPF
.........INTV
CC
to –0.3V
EXTV
CC
..................................................... 10V to –0.3V
I
TH
, V
FB
Voltages ...................................... 2.7V to –0.3V
(Note 1)
FE PACKAGE
20-LEAD PLASTIC TSSOP
1
2
3
4
5
6
7
8
9
10
TOP VIEW
20
19
18
17
16
15
14
13
12
11
CLKOUT
PLLLPF
I
TH
TRACKS/SS
V
FB
SGND
PGND
BG
INTV
CC
EXTV
CC
PHASMD
PLLIN/MODE
PGOOD
SENSE
+
SENSE
–
RUN
BOOST
TG
SW
V
IN
21
SGND
T
JMAX
= 125°C, q
JA
= 35°C/W
EXPOSED PAD (PIN 21) IS SGND MUST BE SOLDERED TO PCB
20 19 18 17
7 8
TOP VIEW
UFD PACKAGE
20-PIN (4mm × 5mm) PLASTIC QFN
9 10
6
5
4
3
2
1
11
12
13
14
15
16
I
TH
TRACK/SS
V
FB
SGND
PGND
BG
PGOOD
SENSE
+
SENSE
–
RUN
BOOST
TG
PLLLPF
CLKOUT
PHASMD
PLLIN/MODE
INTV
CC
EXTV
CC
V
IN
SW
21
SGND
T
JMAX
= 125°C, q
JA
= 37°C/W
EXPOSED PAD (PIN 21) IS SGND MUST BE SOLDERED TO PCB
PIN CONFIGURATION
Peak Output Current <10µs (TG,BG) ...........................3A
INTV
CC
Peak Output Current ................................. 50mA
Operating Temperature Range (Note 2)....–40°C to 85°C
Junction Temperature (Note 3)
............................. 125°C
Storage Temperature Range
FE Package ........................................ –65°C to 150°C
Storage Temperature Range
UFD Package .................................... –65°C to 125°C
Lead Temperature (FE Package, Soldering, 10 sec)
... 300°C
LTC3835
3
3835fe
For more information www.linear.com/LTC3835
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loops
V
FB
Regulated Feedback Voltage (Note 4); I
TH
Voltage = 1.2V
l
0.792 0.800 0.808 V
I
VFB
Feedback Current (Note 4) –5 –50 nA
V
REFLNREG
Reference Voltage Line Regulation V
IN
= 4V to 30V (Note 4) 0.002 0.02 %/V
V
LOADREG
Output Voltage Load Regulation (Note 4)
Measured in Servo Loop; ∆I
TH
Voltage = 1.2V to 0.7V
Measured in Servo Loop; ∆I
TH
Voltage = 1.2V to 2V
l
l
0.1
–0.1
0.5
–0.5
%
%
g
m
Transconductance Amplifier g
m
I
TH
= 1.2V; Sink/Source 5µA (Note 4) 1.55 mmho
I
Q
Input DC Supply Current
Sleep Mode
Shutdown
(Note 5)
RUN = 5V, V
FB
= 0.83V (No Load)
V
RUN
= 0V
80
10
125
20
µA
µA
UVLO Undervoltage Lockout V
IN
Ramping Down
l
3.5 4 V
V
OVL
Feedback Overvoltage Lockout Measured at V
FB
Relative to Regulated V
FB
8 10 12 %
I
SENSE
Sense Pins Total Source Current V
SENSE
– = V
SENSE
+ = 0V –660 µA
DF
MAX
Maximum Duty Factor In Dropout 98 99.4 %
I
TRACK/SS
Soft-Start Charge Current V
TRACK
= 0V 0.75 1.0 1.35 µA
V
RUN
ON RUN Pin ON Threshold V
RUN
Rising 0.5 0.7 0.9 V
V
SENSE(MAX)
Maximum Current Sense Threshold V
FB
= 0.7V, V
SENSE
– = 3.3V
V
FB
= 0.7V, V
SENSE
– = 3.3V
l
90
80
100
100
110
115
mV
mV
TG t
r
TG t
f
TG Transition Time:
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
50
50
90
90
ns
ns
BG t
r
BG t
f
BG Transition Time:
Rise Time
Fall Time
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
40
40
90
80
ns
ns
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
RUN
= 5V unless otherwise noted.
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3835EFE#PBF LTC3835EFE#TRPBF LTC3835EFE 20-Lead Plastic TSSOP –40°C to 85°C
LTC3835IFE#PBF LTC3835IFE#TRPBF LTC3835IFE 20-Lead Plastic TSSOP –40°C to 85°C
LTC3835EUFD#PBF LTC3835EUFD#TRPBF 3835 20-Pin (4mm × 5mm) Plastic DFN –40°C to 85°C
LTC3835IUFD#PBF LTC3835IUFD#TRPBF 3835 20-Pin (4mm × 5mm) Plastic DFN –40°C to 85°C
LEAD BASED FINISH TAPE
AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3835EFE LTC3835EFE#TR LTC3835EFE 20-Lead Plastic TSSOP –40°C to 85°C
LTC3835IFE LTC3835IFE#TR LTC3835IFE 20-Lead Plastic TSSOP –40°C to 85°C
LTC3835EUFD LTC3835EUFD#TR 3835 20-Pin (4mm × 5mm) Plastic DFN –40°C to 85°C
LTC3835IUFD LTC3835IUFD#TR 3835 20-Pin (4mm × 5mm) Plastic DFN –40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature
ranges. *The temperature grade is identified by a label on the shipping container.
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/
(Note 2)
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LTC3835EUFD#PBF

Mfr. #:
Buy LTC3835EUFD#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators L IQ Sync Buck Cntr
Lifecycle:
New from this manufacturer.
Delivery:
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