LTC3617_15 Datasheet, PDF (1/20 Pages) Linear Technology – 6A Monolithic Synchronous Step-Down Regulator for DDR Termination

LTC3617
±6A Monolithic Synchronous
Step-Down Regulator
for DDR Termination
Features
n _{±6A Output Current}
n _{2.25V to 5.5V Input Voltage Range}
n _{±10mV Output Voltage Accuracy}
n _{Optimized for Low Output Voltages Down to 0.5V}
n _{High Efficiency}
n _{Integrated Buffer for VTTR = VDDQIN • 0.5}
n _{Shutdown Current: <1µA}
n _{Adjustable Switching Frequency: Up to 4MHz}
n _{Optional Internal Compensation}
n _{Internal Soft-Start}
n _{Power Good Status Output}
n _{Input Overvoltage Protected}
n _{Thermally Enhanced 24-Pin 3mm × 5mm}
QFN Package
Applications
n _{DDR Termination}
n _{Supports DDR, DDR2 and DDR3 Standards}
n _{Tracking Supplies}
Description
The LTC^®3617 is a high efficiency monolithic synchronous
buck regulator utilizing a current mode, constant frequency
architecture. It operates from an input voltage range of
2.25V to 5.5V and provides a regulated output voltage
equal to 0.5 • VDDQIN while sourcing and sinking up to
6A of load current. An internal amplifier provides a VTTR
output voltage equal to 0.5 • VDDQIN with an output cur-
rent capability of ±10mA.
The operating frequency is externally programmable up to
4MHz, allowing the use of small surface mount inductors.
For switching-noise-sensitive applications, the LTC3617
can be synchronized to an external clock up to 4MHz.
Forced continuous mode operation in the LTC3617 reduces
noise and RF interference. Adjustable external compensa-
tion allows the transient response to be optimized over a
wide range of loads and output capacitors.
The internal synchronous switch increases efficiency and
eliminates the need for an external catch diode, minimizing
external component count and board space. The LTC3617
is offered in a leadless 24-pin 3mm × 5mm thermally
enhanced QFN package.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners. Protected by U.S. Patents, including 6580258, 5481178, 6498466, 6611131.
Typical Application
V_IN
2.5V
22µF
SV_IN
PV_IN
×4
RUN
VTTR
V_REF
1.25V
VDDQIN
0.1µF ±10mA
RT
LTC3617
0.15µH
VTT
SW
1.25V
PGOOD
SGND
47µF ^±6A
ITH
PGND
×2
SYNC
V_FB
3617 TA01a
100
90
80
70
60
50
40
30
20
10
0
0.1
Efficiency and Power Loss
vs Load Current
10
1
0.1
1
LOAD CURRENT (A)
0.01
10
3617 TA01b
3617fa
1