LTC3833
Fast Accurate Step-Down
DC/DC Controller with
Differential Output Sensing
FEATURES DESCRIPTION
n
Wide V Range: 4.5V to 38V
The LTC 3833 is a synchronous step-down DC/DC
IN
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V Range: 0.6V to 5.5V
switching regulator controller targeted for high power
OUT
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Output Accuracy: 0.25% at 25C and 0.67%
applications. It drives all N-channel power MOSFETs. The
over Temperature
controlled on-time valley current mode architecture allows
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Differential Output Sensing Allowing Up to 500mV
for both fast transient response and constant frequency
Line Loss
switching in steady-state operation, independent of V ,
IN
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Fast Load Transient Response
V and load current.
OUT
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t = 20ns, t = 90ns
ON(MIN) OFF(MIN)
Differential output voltage sensing along with a precision
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Controlled On-Time Valley Current Mode
internal reference combine to offer 0.67% output regula-
Architecture
tion and the ability to correct for up to 500mV variations
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Frequency Programmable from 200kHz to 2MHz
in the output terminals due to line losses. The operating
and Synchronizable to External Clock
frequency can be programmed from 200kHz to 2MHz with
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R or Inductor DCR Current Sensing
SENSE
an external resistor and can be synchronized to an external
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Overvoltage Protection and Current Limit Foldback
clock for noise and EMI sensitive applications.
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Power Good Output Voltage Monitor
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Very low t and t times allow for near 0% and near
Output Tracking or Adjustable Soft-Start
ON OFF
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100% duty cycles, respectively. Programmable soft-start or
External V Input for Bypassing Internal LDO
CC
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output voltage tracking is available. Safety features include
20-Pin QFN (3mm 4mm) and TSSOP Packages
output overvoltage protection, programmable current limit
APPLICATIONS
with foldback, and a power good output signal.
n L, LT, LTC, LTM, OPTI-LOOP, PolyPhase, Module, Linear Technology and the Linear logo
Distributed Power Systems
are registered trademarks and Hot Swap, No R and UltraFast are trademarks of Linear
SENSE
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Point-of-Load Converters Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 5481178, 5487554, 6580258, 6304066, 6476589,
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Computing Systems
6774611.
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Datacomm Systems
TYPICAL APPLICATION
1.5V, 20A, 300kHz High Current Step-Down Converter
INTV
CC Efficiency
V
IN
V V
RNG IN
100
4.5V TO 14V
V 180F PULSE-SKIPPING
OUT
MODE
SENSE
100k
90
+
PGOOD
SENSE
0.1F
3.24k
RUN TG
FORCED
80
LTC3833
CONTINUOUS
0.1F SW
0.47H
V
OUT
MODE
TRACK/SS 1.5V
BOOST 70
20A
470pF
15k
0.1F
10k
I INTV INTV
TH CC CC 330F 60
137k 4.7F
2
RT
10k
50
EXTV
CC BG
V = 12V
IN
V = 1.5V
OUT
SGND PGND
40
300kHz
MODE/PLLIN 0.1 1 10 100
+
V
OSNS
LOAD CURRENT (A)
3833 TA01a
V
OSNS
3833 TA01b
3833f
1
EFFICIENCY (%)LTC3833
ABSOLUTE MAXIMUM RATINGS (Note 1)
V Voltage ................................................ 0.3V to 40V Operating Junction Temperature Range
IN
BOOST Voltage .......................................... 0.3V to 46V (Notes 2, 3, 4) ........................................ 40C to 125C
SW Voltage ................................................... 5V to 40V Storage Temperature Range .................. 65C to 150C
INTV , EXTV , (BOOST-SW), PGOOD, RUN, Lead Temperature (Soldering, 10 sec)
CC CC
MODE/PLLIN, V Voltages ....................... 0.3V to 6V FE Package .......................................................300C
RNG
+
V , SENSE , SENSE Voltages .................. 0.6V to 6V
OUT
+
V , V Voltages ........ 0.6V to (INTV + 0.3V)
OSNS OSNS CC
RT, ITH Voltages ..................... 0.3V to (INTV + 0.3V)
CC
TRACK/SS Voltages ..................................... 0.3V to 5V
PIN CONFIGURATION
TOP VIEW
TOP VIEW
PGOOD 1
20 BOOST
20 19 18 17
+
SENSE 2
19 TG
V 1 16 BOOST
OSNS
SENSE 3 SW
18
+
V 2 15 TG
OSNS
V 4 BG
17
OUT
TRACK/SS 3 14 SW
21
V 5 PGND
16
OSNS
21
SGND
ITH 4 13 BG
+
SGND
V 6 INTV
15
OSNS CC
V 5 12 PGND
RNG
TRACK/SS 7
14 V
IN
RT 6 11 INTV
CC
ITH 8
13 MODE/PLLIN
7 8 9 10
V 9
12 EXTV
RNG CC
RT 10
11 RUN
FE PACKAGE
20-LEAD PLASTIC TSSOP
UDC PACKAGE
T = 125C, = 38C/W
JMAX JA
20-LEAD (3mm 4mm) PLASTIC QFN
EXPOSED PAD (PIN 21) IS SGND, MUST BE SOLDERED TO PCB
T = 125C, = 43C/W
JMAX JA
EXPOSED PAD (PIN 21) IS SGND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3833EUDC#PBF LTC3833EUDC#TRPBF LFGT 20-Lead (3mm 4mm) Plastic QFN 40C to 125C
LTC3833IUDC#PBF LTC3833IUDC#TRPBF LFGT 20-Lead (3mm 4mm) Plastic QFN 40C to 125C
LTC3833EFE#PBF LTC3833EFE#TRPBF LTC3833FE 20-Lead Plastic TSSOP 40C to 125C
LTC3833IFE#PBF LTC3833IFE#TRPBF LTC3833FE 20-Lead Plastic TSSOP 40C to 125C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: