LTC3115-2_15 Datasheet, PDF (1/42 Pages) Linear Technology – 40V, 2A Synchronous Buck-Boost DC/DC Converter

LTC3115-2
40V, 2A Synchronous
Buck-Boost DC/DC Converter
Features
n _{Wide VIN Range: 2.7V to 40V}
n _{Wide VOUT Range: 2.7V to 40V}
n _{0.8A Output Current for VIN ≥ 3.6V, VOUT = 5V}
n _{2A Output Current in Step-Down Operation}
for V_IN ≥ 6V
n _{Programmable Frequency: 100kHz to 2MHz}
n _{Synchronizable Up to 2MHz with an External Clock}
n _{Up to 95% Efficiency}
n _{30µA No-Load Quiescent Current in Burst Mode}^®
Operation
n _{Ultralow Noise Buck-Boost PWM}
n _{Internal Soft-Start}
n _{3µA Supply Current in Shutdown}
n _{Programmable Input Undervoltage Lockout}
n _{Small 4mm × 5mm × 0.75mm DFN Package}
n _{Thermally Enhanced 20-Lead TSSOP Package}
Applications
n _{24V/28V Industrial Applications}
n _{Automotive Power Systems}
n _{Telecom, Servers and Networking Equipment}
n _{FireWire Regulator}
n _{Multiple Power Source Supplies}
Description
The LTC^®3115-2 is a high voltage monolithic synchronous
buck-boost DC/DC converter optimized for applications
subject to fast (<1ms) input voltage transients. For all other
applications, the LTC3115-1 is recommended. With its wide
2.7V to 40V input and output voltage ranges, the LTC3115-2
is well suited for use in a wide variety of automotive and
industrial power supplies. A proprietary low noise switch-
ing 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 value in-
ductors for miniaturization of the application circuit. Pin se-
lectable Burst Mode operation reduces standby current and
improves light load efficiency which, combined with a 3µA
shutdown current, make the LTC3115-2 ideally suited for
battery-powered applications. Additional features include
output disconnect in shutdown, short-circuit protection
and internal soft-start. The LTC3115-2 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.
Typical Application
5V, 750kHz Wide Input Voltage Range Buck-Boost Regulator
10µH
Efficiency vs V_IN
95
I_LOAD = 0.5A
0.1µF
0.1µF
90
2.7V TO
40V
4.7µF
BST1 SW1
PV_IN
V_IN
SW2 BST2
PV_OUT
47µF × 2
5V
0.8A V_IN > 3.6V
85
2A V_IN ≥ 6V
LTC3115-2
3300pF ^1M
33pF
80
137k
BURST PWM PWM/SYNC
VC
15k
I_LOAD = 1A
OFF ON RUN
RT
47.5k
GND
PGND
FB
PV_CC
V_CC
4.7µF
249k
(OPTIONAL)
31152 TA01a
75
70
2
V_OUT = 5V
10
40
INPUT VOLTAGE (V)
31152 TA01b
For more information www.linear.com/LTC3115-2
31152fa
1