Datasheet

TLV2711, TLV2711Y
Advanced LinCMOS RAIL-TO-RAIL
MICROPOWER SINGLE OPERATIONAL AMPLIFIERS
SLOS196A – AUGUST 1997 – REVISED MARCH 2001
24
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
– Unity-Gain Bandwidth – kHz
UNITY-GAIN BANDWIDTH
vs
LOAD CAPACITANCE
C
L
– Load Capacitance – pF
B
1
60
10
40
0
80
50
70
20
30
10
1
10
2
10
3
10
4
10
5
T
A
= 25°C
10
6
Figure 52
APPLICATION INFORMATION
driving large capacitive loads
The TLV2711 is designed to drive larger capacitive loads than most CMOS operational amplifiers. Figure 50
and Figure 51 illustrate its ability to drive loads up to 600 pF while maintaining good gain and phase margins
(R
null
= 0).
A smaller series resistor (R
null
) at the output of the device (see Figure 53) improves the gain and phase margins
when driving large capacitive loads. Figure 50 and Figure 51 show the effects of adding series resistances of
500 and 1000 . The addition of this series resistor has two effects: the first is that it adds a zero to the transfer
function and the second is that it reduces the frequency of the pole associated with the output load in the transfer
function.
The zero introduced to the transfer function is equal to the series resistance times the load capacitance. To
calculate the improvement in phase margin, equation 1 can be used.
∆φ
m1
tan
–1
2 ×π×UGBW × R
null
× C
L
∆φ
m1
Improvement in phase margin
UGBW Unity-gain bandwidth frequency
R
null
Output series resistance
C
L
: Load capacitance
(1)
Where :