TLV2217
LOW DROPOUT FIXED VOLTAGE REGULATORS
SLVS067K − MARCH 1992 − REVISED AUGUST 2004
COMPENSATION-CAPACITOR SELECTION INFORMATION
The TLV2217 is a low-dropout regulator. This means that the capacitance loading is important to the performance
of the regulator because it is a vital part of the control loop. The capacitor value and the equivalent series resistance
(ESR) both affect the control loop and must be defined for the load range and the temperature range. Figures 1 and 2
can be used to establish the capacitance value and ESR range for the best regulator performance.
TLV2217
ESR OF OUTPUT CAPACITOR
vs
LOAD CURRENT
3
ESR − Equivalent Series Resistance −
Ω
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0.04
0.035
TLV2217
STABILITY
vs
ESR
0.03
0.025
C
L
Maximum
ESR Boundary
0.02
0.015
Minimum
ESR Boundary
0.01
0.005
0
0
0.1
0.2
0.3
0.4
0.5
IL − Load Current − A
Applied Load
Current
Load
Voltage
∆I
L
∆V
L
∆V
L = ESR
× ∆I
L
Figure 1
typical application schematic
TLV2217-33
INPUT
3.8 V
OUTPUT
GND
0.1
µF
22
µF
VO = 3.3 V
Figure 3
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇ
Region of
Best Stability
400
µF
200
µF
100 mF
22
µF
1.5
10
µF
1
0
0.5
2
2.5
3
3.5
4
4.5
5
1/ESR
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇÇÇÇÇ
ÇÇÇ
ÇÇÇ
CL = 22
µF
CI = 0.1
µF
TJ = 25°C
Not Recommended
Potential Instability
Not Recommended
Potential Instability
Recommended Minimum ESR
1000
µF
Figure 2
5
TI [ TEXAS INSTRUMENTS ]
