600mA Voltage-Scaling Step-Down Converter
for RF Power Amplifiers with Bypass Switch
Typical Characteristics
P-Channel R
DS(ON)
vs. Input Voltage
400
350
140
AAT1171
Bypass R
DS(ON)
vs. Input Voltage
T
J
= 120°C
T
J
= 85°C
T
J
= 120°C
T
J
= 85°C
120
R
DS(ON)
(mΩ)
Ω
250
200
150
100
50
0
2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1
4.3 4.5 4.7 4.9 5.1 5.3 5.5
R
DS(ON)
(mΩ)
Ω
300
100
80
60
40
20
0
2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5
T
J
= 25°C
T
J
= 25°C
Input Voltage (V)
Input Voltage (V)
Switching Frequency vs. Temperature
(V
IN
= 3.6V; V
OUT
= 1.8V; R
L
= 10)
Output Voltage vs. DAC Voltage
(V
IN
= 4.2V; LL Mode)
4.5
4.0
Switching Frequency (MHz)
2.06
Output Voltage (V)
2.04
2.02
2.00
1.98
1.96
1.94
1.92
1.90
-40.0
-20.0
0.0
20.0
40.0
60.0
80.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0.2
0.4
0.6
0.8
25°C
85°C
-40°C
PWM
LL
1.0
1.2
1.4
°
Temperature (°C)
DAC Voltage (V)
Heavy Load Switching Waveform
(V
IN
= 3.6V; V
OUT
= 1.8V; R
L
= 3Ω; C
OUT
= 4.7µF; L = 2.2µH)
V
OUT
(AC coupled)
20mV/div
I
L
200mA/div
0
V
LX
2V/div
0
Time (200ns/div)
1171.2006.06.1.0
9
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
