LTC3815_15 Datasheet, PDF (1/42 Pages) Linear Technology – 6A Monolithic Synchronous DC/DC Step-Down Converter with Digital Power System Management

Electrical Specifications Subject to Change
LTC3815
6A Monolithic Synchronous
DC/DC Step-Down Converter with
Digital Power System Management
Features
Description
nn _{2.25V to 5.5V Input Voltage Range}
nn _{±1% Total Output Voltage Accuracy Over}
Temperature at V_IN = 3.3V or 5V
nn _{Single Resistor-Programmable Output Voltage}
nn _{PMBus Compliant Serial Interface:}
nn _{Programmable Output Voltage Margining:}
Up to ±25% V_OUT Range with 0.1% Resolution
nn _{Read back of Average and Peak Temperature,}
Current, and Voltage (25Hz Refresh Rate)
nn _{Fault Status}
nn _{Phase-Lockable Fixed Frequency Up to 3MHz}
nn _{Less Than 1ms Power-Up Time}
nn _{Integrated 13-Bit ADC}
nn _{Optional External Reference Input}
nn _{Pin Selectable Fast-Margining of the Output Voltage}
nn _{Power Good Flag with Pin Programmable Thresholds}
and Filter Delay
nn _{Differential Remote Output Voltage Sensing}
nn _{Master Shutdown Mode: <1μA Supply Current}
nn _{Clock Out for 2-Phase Operation (12A Output Current)}
nn _{Available in a Thermally-Enhanced 38-Lead}
4mm × 6mm QFN Package
Applications
nn _{Intelligent Energy Efficient Power Conversion}
nn _{ASIC/FPGA/Processor Power}
nn _{Distributed Power Systems}
nn _{Point of Load Power Conversion}
The LTC^®3815 is a high efficiency, 6A monolithic synchro-
nous buck regulator using a phase lockable controlled
on-time, current mode architecture. The output voltage
is programmable from 0.4V to 72% of V_IN with a single
external resistor or an external voltage reference through
the reference input (REF) pin. The output voltage can be
margined up or down up to 25% with 0.1% resolution via
a PMBus-compliant serial interface. The serial interface
can also be used to read back fault status and both time-
averaged (~4ms) and peak input/output current, input/
output voltage, and temperature. System configuration
and monitoring is supported by the LTpowerPlay™ de-
velopment system.
The architecture provides extremely fast transient response
and allows operation at the very low on-times required to
regulate low output voltages at high switching frequencies.
The operating frequency is programmable from 400kHz
to 3MHz with an external resistor or for noise sensitive
applications, it can be synchronized to an external clock
over the same range. The operating supply voltage range
is from 2.25V to 5.5V making it suitable for operation from
2.5V, 3.3V or 5V rails or Lithium-Ion batteries.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap and LTPowerPlay are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents including
5481178, 5705919, 5929620, 6144194, 6177787, 6580258, 5408150, 7420359. Licensed
under U.S. Patent 7000125 and other related patents worldwide.
Typical Application
V_IN
2.25V TO 5.5V
PMBUS
PV_IN
V_IN
LTC3815
MODE/SYNC
PGLIM
R_T
RUN_MSTR
TRACK/SS
RUN_STBY
SCL, SDA, ALERT
MARGIN
WP
PGOOD
CLKOUT
CSLEW
REF
ASEL
SW
V_{CC_SENSE}
V_{SS_SENSE}
DA_OUT
FB
I_TH
PGFD
C_IN
L
R_C1
R_{C2 CC2}
V_OUT
0.4V TO 0.72*V_IN
6A
C_OUT
3815 TA01a
Efficiency and Power Loss
vs Load Current
100
10
V_OUT = 1.8V
90
80
EFFICIENCY
70
1
60
50
40
POWER LOSS
30
0.1
20
10
0
10
V_IN = 2.8V
V_IN = 3.3V
V_IN = 5V ₀
100
1000
10000
LOAD CURRENT (mA)
3815 TA01b
For more information www.linear.com/LTC3815
3815p
1