AAT1152 Advanced Analogic Technologies, AAT1152 Datasheet - Page 10

• Manufacturer Part Number: AAT1152
• Description: 850kHz 1A Synchronous Buck DC/DC Converter
• Manufacturer: Advanced Analogic Technologies

Power and Signal Source
Separate small signal ground and power supply
pins isolate the internal control circuitry from the
noise associated with the output MOSFET switch-
ing. The low pass filter R1 and C3 in schematic fig-
ures 3 and 4 filters the noise associated with the
power switching.
10
V
V
OUT
0.5A/div
IN
Enable
2V/div
1V/div
=3.6V
=1.5V
3.5
2.5
1.5
0.5
I
L
3
2
1
0
V
=1A
OUT
0
I
L
V
V
Figure 4 schematic
V
V
Figure 3 schematic
850kHz 1A Synchronous Buck DC/DC Converter
CC
O
CC
O
= 3.3V
= 1.5V
Current Limit Characteristic
=V
=V
Figure 1: Inrush Limit
0.5
P
P
= 5.0V
=3.6V
Figure 2.
200 sec/div
1
I
OUT
(A)
Current Limit and Over-temperature
protection
For overload conditions the peak input current is
limited. Figure 2 displays the VI current limit char-
acteristics. As load impedance decreases and the
output voltage falls closer to zero, more power is
dissipated internally, raising the device tempera-
ture. Thermal protection completely disables
switching when internal dissipation becomes
excessive, protecting the device from damage. The
junction over-temperature threshold is 140°C with
15°C of hysteresis.
1.5
2
2.5
AAT1152
1152.2003.01.0.9