LTC3834
30µA I Synchronous
Q
Step-Down Controller
FEATURES
DESCRIPTION
TheLTC®3834isahighperformancestep-downswitching
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.
n
Wide Output Voltage Range: 0.8V ≤ V
≤ 10V
OUT
n
Low Operating Quiescent Current: 30μA
OPTI-LOOP® Compensation Minimizes C
1% Output Voltage Accuracy
n
n
n
n
n
n
n
n
n
n
n
n
n
n
OUT
Wide V Range: 4V to 36V
IN
Phase-Lockable Fixed Frequency 140kHz to 650kHz
Dual N-Channel MOSFET Synchronous Drive
Very Low Dropout Operation: 99% Duty Cycle
Adjustable Output Voltage Soft-Start or Tracking
Output Current Foldback Limiting
The 30μA 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
LTC3834 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.
Power Good Output Voltage Monitor
Clock Output for PolyPhase® Applications
Output Overvoltage Protection
The TRACK/SS pin ramps the output voltage during
start-up. Current foldback limits MOSFET heat dissipa-
tion during short-circuit conditions. A reduced feature set
version of the part (LTC3834-1) is available in a smaller,
lower pin count package.
Low Shutdown I : 4μA
Q
Internal LDO Powers Gate Drive from V or V
IN
OUT
Selectable Continuous, Pulse Skipping or
Burst Mode® Operation at Light Loads
n
Small 20-Lead TSSOP or 4mm × 5mm QFN Package
Comparison of LTC3834 and LTC3834-1
CLKOUT/
APPLICATIONS
PART #
PHASMD EXTV
PGOOD
Yes
PACKAGES
CC
LTC3834
LTC3834-1
Yes
No
Yes
No
FE20/4mm × 5mm QFN
GN16/3mm × 5mm DFN
n
Automotive Systems
No
n
Telecom Systems
L, LT, LTC, LTM, Burst Mode, PolyPhase and OPTI-LOOP are registered trademarks 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.
n
Battery-Operated Digital Devices
n
Distributed DC Power Systems
TYPICAL APPLICATION
High Efficiency Synchronous Step-Down Converter
V
IN
4V TO 36V
CLKOUT
PLLLPF
RUN
V
IN
10000
1000
100
10
100
90
10μF
TG
0.01μF
0.22μF
PGOOD
TRACK/SS
80
BOOST
SW
70
3.3μH
V
OUT
3.3V
5A
0.012Ω
I
TH
560pF
54.2k
60
50
LTC3834
150pF
150μF
40
30
20
10
SGND
PLLIN/MODE
INTV
EXTV
CC
CC
4.7μF
68.1k
1
V
BG
FB
–
+
SENSE
SENSE
0
0.1
215k
0.000001
0.0001
OUTPUT CURRENT (A)
0.01
1
PGND
3834 TA01b
3834 TA01
3834fb
1