Datasheet

ADP1621 Data Sheet
Rev. B | Page 4 of 32
Parameter Symbol Conditions Min Typ Max Unit
GATE DRIVER
GATE Rise Time
9
t
R
C
GAT E
= 3.3 nF 17 ns
GATE Fall Time
9
t
F
C
GAT E
= 3.3 nF 13 ns
1
The maximum input voltage is the shunt regulation voltage, which is typically 5.5 V and can range from 5.3 V to 6.0 V over the specified temperature range.
2
The ADP1621 is tested in a feedback servo loop, which servos V
FB
to the internal reference voltage. The voltage change in FB is measured while V
IN
is changed from
2.9 V to 5 V. The line regulation is calculated by (∆V
FB
/V
FB
) × 100%/∆V
IN
.
3
The ADP1621 is tested in a feedback servo loop, which servos V
FB
to the internal reference voltage, and V
COMP
is forced from 1.4 V to 1.5 V. The V
COMP
range is
(1.0 V ≤ V
COMP
≤ 2.0 V).
4
The peak slope-compensation current at the CS pin is typically 70 µA, and effectively clamped at 116 mV. Thus, R
S
should not exceed 1.6 kΩ (116 mV/70 µA).
5
Guaranteed by design for thermal shutdown. When the thermal junction temperature of the ADP1621 reaches approximately 150°C, the ADP1621 goes into thermal
shutdown and the GATE voltage is pulled low. When the junction temperature drops below about 140°C, the soft start sequence is initiated and the ADP1621 resumes
normal operation.
6
f
OSC
is the natural oscillation frequency, f
SYNC
is the synchronization frequency, and f
SW
is the switching frequency. If synchronization is used, then f
SW
= f
SYNC
; otherwise, f
SW
= f
OSC
.
7
Guaranteed by design and bench characterization.
8
To ensure proper synchronization operation, set the synchronization frequency, f
SYNC
, to 1.2× of the free-running frequency, f
OSC
. Although the switching frequency can
be synchronized to as high as 1.8 MHz, the peak slope-compensation current decreases at higher synchronization frequencies. It is recommended that the maximum
f
SYNC
be less than 1.4× of f
OSC
and should not exceed 1.8 MHz. The slope-compensation resistor, R
S
, should be chosen for the synchronization frequency (see the Slope
Compensation section in the Application Information: Boost Converter section).
9
GATE rise and fall times are measured from 10% to 90% levels.