User guide

MAX881R
Low-Noise Bias Supply in µMAX
with Power-OK for GaAsFET PA
4 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(Circuit of Figure 3, V
IN
= 3.6V, T
A
= +25°C, unless otherwise noted.)
100µs/div
START-UP FROM SHUTDOWN
(NO LOAD)
+5V
V
OUT
POK
SHDN
MAX881R-TOC10
-2V
0
0
V
IN
0
V
IN
= 3.6V
CIRCUIT OF FIGURE 3b
5µs/div
OUTPUT NOISE AND RIPPLE
(CIRCUIT OF FIGURE 3a)
V
OUT
1mV/div
AC COUPLED
MAX881R-TOC11
V
IN
= 3.6V
V
OUT
= -2V
I
OUT
= 2.5mA
10µs/div
OUTPUT NOISE AND RIPPLE
(CIRCUIT OF FIGURE 3b)
V
OUT
= 0
V
IN
= 0
1mV/div
AC COUPLED
V
OUT
= -2V
V
IN
= 3.6V
1mV/div
AC COUPLED
MAX881R-TOC12
R
L
= 500Ω
NOISE FLOOR
OUTPUT NOISE
60
-40
1 10 100 1000
OUTPUT NOISE SPECTRUM
(CIRCUIT OF FIGURE 3a)
-20
MAX881R TOC13
FREQUENCY (kHz)
NOISE (dBµV)
0
20
40
50
-30
-10
10
30
V
IN
= 3.6V
V
OUT
= -2V
I
OUT
= 2.5mA
60
-40
1 10 100 1000
OUTPUT NOISE SPECTRUM
(CIRCUIT OF FIGURE 3b)
-20
MAX881R TOC14
FREQUENCY (kHz)
NOISE (dBµV)
0
20
40
50
-30
-10
10
30
V
IN
= 3.6V
V
OUT
= -2V
I
OUT
= 4mA
2ms/div
LINE-TRANSIENT RESPONSE
V
IN
V
OUT
MAX881R-TOC15
10mV/
div
3.3V
2.7V
I
LOAD
= 4mA
V
OUT
= -2V
CIRCUIT OF FIGURE 3b
100µs/div
LOAD-TRANSIENT RESPONSE
I
OUT
V
OUT
MAX881R-TOC16
10mV/
div
4mA
400µA
V
IN
= 3.6V
V
OUT
= -2V
CIRCUIT OF FIGURE 3b