LTC3613 Datasheet, PDF (1/36 Pages) Linear Technology – 24V, 15A Monolithic Step Down Regulator

LTC3613
FEATURES
24V, 15A Monolithic
Step Down Regulator with
Differential Output Sensing
DESCRIPTION
n _{Wide VIN Range: 4.5V to 24V;}
V_OUT Range: 0.6V to 5.5V at up to 15A
n _{0.67% Output Voltage Accuracy}
n _{Controlled On-Time Valley Current Mode Architecture,}
Excellent Current Sharing Capability
n _{Frequency Programmable from 200kHz to 1MHz}
and Synchronizable to External Clock
n _{RSENSE or Inductor DCR Current Sensing With}
Accurate Current Limit
n _{Fast Transient Response}
n _{Differential Output Voltage Sensing Allowing 500mV}
Common Mode Remote Ground
n _{tON(MIN) = 65ns; tOFF(MIN) = 105ns}
n _{Overvoltage Protection and Current Limit Foldback}
n _{Power Good Output Voltage Monitor}
n _{Voltage Tracking Start-Up}
n _{External VCC Input for Bypassing Internal LDO}
n _{Micropower Shutdown: IQ = 15μA}
n _{7mm × 9mm 56-pin QFN Package}
APPLICATIONS
n _{Distributed Power System}
n _{Point-of-Load Converters}
n _Servers
The LTC^®3613 is a monolithic synchronous step-down
switching regulator capable of regulating outputs from 0.6V
to 5.5V with up to 15A output current. The controlled on-time
constant frequency valley current mode architecture allows for
both fast transient response and constant frequency switch-
ing in steady-state operation, independent of V_IN, V_OUT and
load. This also provides excellent current sharing capability.
Differential output voltage sensing along with a precision
internal reference combine to offer ±0.67% output regula-
tion, even if the output ground reference deviates from
local ground by 500mV. The switching frequency can be
programmed from 200kHz to 1MHz with an external resis-
tor. The switching frequency is also phase synchronizable
to an external clock in applications where switching noise/
EMI reduction is crucial.
Very low t_ON and t_OFF times allow for near 0% and near 100%
duty cycles, respectively. Voltage tracking soft start-up is
provided for tracking and sequencing applications. Safety fea-
tures include output overvoltage protection, programmable
current limit with foldback, and power good monitoring.
L, LT, LTC, LTM, OPTI-LOOP, Linear Technology and the Linear logo are registered trademarks
and Hot Swap 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
5481178, 5487554, 6580258, 6304066, 6476589, 6774611.
TYPICAL APPLICATION
High Efficiency High Power Step-Down Converter
INTV_CC
PV_IN
SV_IN
100k
0.1μF
47pF
LTC3613
PGOOD
V_OUT
RUN
V_RNG
SENSE^–
SENSE⁺
MODE/PLLIN SW
EXTV_CC
TRACK/SS BOOST
270pF
21k
115k
ITH
RT
SGND
INTV_CC
PGND
V_OSNS+
V_OSNS–
3613 TA01
V_IN
+
4.5V TO 24V
0.1μF
82μF
10Ω
1000pF 10Ω
0.47μH _1.5mΩ
0.1μF
15k
10k
4.7μF
+
V_OUT
1.5V
15A
330μF
×2
Efficiency and Power Loss
vs Load Current
100
3.5
90 ^{PULSE-SKIPPING MODE}
3.0
80
70
2.5
60
FORCED
2.0
50
CONTINUOUS
40
MODE
1.5
30
20
10
0
0.01
1.0
V_IN = 12V ^0.5
V_OUT = 1.5V
0
0.1
1
10
LOAD CURRENT (A)
3613 TA01a
3613fa
1