LTC3115-1
40V, 2A Synchronous
Buck-Boost DC/DC
Converter
FEATURES
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DESCRIPTION
The LTC
®
3115-1 is a high voltage monolithic synchronous
buck-boost DC/DC converter. Its wide 2.7V to 40V input and
output voltage ranges make it well suited to a wide variety
of automotive and industrial applications. A proprietary
low noise switching algorithm optimizes efficiency with
input voltages that are above, below or even equal to the
output voltage and ensures seamless transitions between
operational modes.
Programmable frequency PWM mode operation provides
low noise, high efficiency operation and the ability to syn-
chronize switching to an external clock. Switching frequen-
cies up to 2MHz are supported to allow use of small valued
inductors for miniaturization of the application circuit. Pin
selectable Burst Mode operation reduces standby current
and improves light load efficiency which combined with a
3µA shutdown current make the LTC3115-1 ideally suited for
battery-powered applications. Additional features include
output disconnect in shutdown, short-circuit protection
and internal soft-start. The LTC3115-1 is available in ther-
mally enhanced 16-lead 4mm
×
5mm
×
0.75mm DFN and
20-lead TSSOP packages.
L,
LT, LTC, LTM, Burst Mode, LTspice, 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
6404251, 6166527 and others pending.
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Wide V
IN
Range: 2.7V to 40V
Wide V
OUT
Range: 2.7V to 40V
1A Output Current for V
IN
≥ 3.6V, V
OUT
= 5V
2A Output Current in Step-Down Operation
for V
IN
≥ 6V
Programmable Frequency: 100kHz to 2MHz
Synchronizable Up to 2MHz with an External Clock
Up to 95% Efficiency
30µA No-Load Quiescent Current in Burst Mode
®
Operation
Ultralow Noise Buck-Boost PWM
Internal Soft-Start
3µA Supply Current in Shutdown
Programmable Input Undervoltage Lockout
Small 4mm
×
5mm
×
0.75mm DFN Package
Thermally Enhanced 20-Lead TSSOP Package
APPLICATIONS
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24V/28V Industrial Applications
Automotive Power Systems
Telecom, Servers and Networking Equipment
FireWire Regulator
Multiple Power Source Supplies
TYPICAL APPLICATION
10µH
0.1µF
2.7V TO
40V
BST1 SW1
4.7µF
PV
IN
V
IN
SW2 BST2
PV
OUT
LTC3115-1
VC
FB
PV
CC
V
CC
GND
PGND
4.7µF
249k
(OPTIONAL)
70
3115 TA01a
Efficiency vs V
IN
95
0.1µF
5V
1A V
IN
> 3.6V
2A V
IN
≥ 6V
1M
33pF
15k
90
EFFICIENCY (%)
85
I
LOAD
= 0.5A
I
LOAD
= 1A
47µF
60.4k
3300pF
BURST PWM
OFF ON
PWM/SYNC
RUN
RT
80
75
47.5k
2
10
INPUT VOLTAGE (V)
40
31151 TA01b
31151f
1
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
