LTC3616 Datasheet, PDF (8/28 Pages) Linear Technology – 6A, 4MHz Monolithic Synchronous Step-Down DC/DC Converter

LTC3616
TYPICAL PERFORMANCE CHARACTERISTICS V_IN = 3.3V, RT/SYNC = SV_IN unless otherwise noted.
Start-Up from Shutdown with
Prebiased Output
(Forced Continuous Mode)
PGOOD
5V/DIV
Output Voltage During Sinking
vs Input Voltage (V_OUT = 1.8V,
0.47μH Inductor)
1.88
1.86
V_OUT
500mV/DIV
I_L
5A/DIV
1.84
1.82
–3A, 2MHz, 120°C
1.80
–3A, 2MHz, 25°C
1.78
1.76
50μs/DIV
PREBIASED V_OUT = 2.2V
V_OUT = 1.2V, I_OUT = 0A
V_MODE = 1.5V
3616 G31
1.74
2.25
2.75 3.25 4
4.5
INPUT VOLTAGE (V)
5.25
3616 G32
PIN FUNCTIONS
SRLIM/DDR (Pin 1): Slew Rate Limit. Tying this pin to
ground selects maximum slew rate. Minimum slew rate
is selected when the pin is open. Connecting a resistor
from SRLIM/DDR to ground allows the slew rate to be
continuously adjusted. If SRLIM/DDR is tied to S_VIN, DDR
mode is selected. In DDR mode the slew rate limit is set
to maximum.
RT/SYNC (Pin 2): Oscillator Frequency. This pin provides
three ways of setting the constant switching frequency:
1. Connecting a resistor from RT/SYNC to ground will set
the switching frequency based on the resistor value.
2. Driving the RT/SYNC pin with an external clock signal
will synchronize the LTC3616 to the applied frequency.
The slope compensation is automatically adapted to the
external clock frequency.
3. Tying the RT/SYNC pin to SV_IN enables the internal
2.25MHz oscillator frequency.
SGND (Pin 3): Signal Ground. All small-signal and compen-
sation components should connect to this ground, which
in turn should connect to PGND at a single point.
PV_IN (Pins 4, 10, 11, 17): Power Input Supply. PV_IN con-
nects to the source of the internal P-channel power MOSFET.
This pin is independent of SV_IN and may be connected to
the same voltage or to a lower voltage supply.
SW (Pins 5, 6, 7, 8, 13, 14, 15, 16): Switch Node. Con-
nection to the inductor. These pins connect to the drains
of the internal synchronous power MOSFET switches.
NC (Pins 9, 12): Can be connected to ground or left
open.
SV_IN (Pin 18): Signal Input Supply. This pin powers the
internal control circuitry and is monitored by the under-
voltage lockout comparator.
3616f
8