LTC3834 Datasheet, PDF (1/28 Pages) Linear Technology – 30μA IQ Synchronous Step-Down Controller

FEATURES
n _{Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 10V}
n _{Low Operating Quiescent Current: 30μA}
n _OPTI-LOOP^® _{Compensation Minimizes COUT}
n _{±1% Output Voltage Accuracy}
n _{Wide VIN Range: 4V to 36V}
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 IQ: 4μA}
n _{Internal LDO Powers Gate Drive from VIN or VOUT}
n _{Selectable Continuous, Pulse Skipping or}
Burst Mode^® Operation at Light Loads
n _{Small 20-Lead TSSOP or 4mm × 5mm QFN Package}
APPLICATIONS
n _{Automotive Systems}
n _{Telecom Systems}
n _{Battery-Operated Digital Devices}
n _{Distributed DC Power Systems}
LTC3834
30µA I_Q Synchronous
Step-Down Controller
DESCRIPTION
The LTC^®3834 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 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.
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.
Comparison of LTC3834 and LTC3834-1
PART #
LTC3834
CLKOUT/
PHASMD
Yes
EXTV_CC
Yes
PGOOD
Yes
PACKAGES
FE20/4mm × 5mm QFN
LTC3834-1 No
No
No GN16/3mm × 5mm DFN
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.
TYPICAL APPLICATION
High Efficiency Synchronous Step-Down Converter
0.01μF
560pF
54.2k
68.1k
215k
150pF
CLKOUT
V_IN
PLLLPF
RUN
TG
PGOOD
TRACK/SS
BOOST
I_TH
LTC3834
SW
SGND
PLLIN/MODE
V_FB
SENSE^–
SENSE⁺
INTV_CC
EXTV_CC
BG
PGND
0.22μF
4.7μF
V_IN
4V TO 36V
10μF
3.3μH _0.012Ω
V_OUT
3.3V
5A
150μF
3834 TA01
100
90
80
70
60
50
40
30
20
10
0
0.000001
0.0001
0.01
OUTPUT CURRENT (A)
10000
1000
100
10
1
0.1
1
3834 TA01b
3834fb
1