Voltage Supervisor SOT23 Evaluation Board User’s Guide
DS51510B-page 22
©
2006 Microchip Technology Inc.
TABLE C-1:
MICROCHIP ANALOG DEVICES AND SOT23 EVAL BOARD
CIRCUIT/FOOTPRINT OPTION SELECTION
C.3
IDEAS ON EVALUATING AN LDO
One of the characteristics that a designer may wish to evaluate on a LDO is how the
LDO responds to transient loads. Figure C-2 shows a system block diagram for
evaluating a LDO and a typical waveform response (at test point) for the function
generator signal. The output of the function generator connects to a BJT transistor to
simulate the fast switching loads of the circuit.
The value of C2, R3 and C
L
will depend on the LDO used and the load of the circuit.
Look at both the worst-case amplitude load requirements for a loaded and unloaded
system. As the output response of the LDOs become faster, the selection of a smaller
(cheaper) output load capacitor (C
L
) becomes possible (for the same system
performance).
FIGURE C-2:
LDO EVALUATION SYSTEM
Device
Device Family
Supported
on
Comment/
Recommended Component Values:
MCP1700
LDO
Option 2
C1 = 1 µF Ceramic
C2 = 1 µF Ceramic
MCP1701
LDO
Option 2
C1 = 1 µF Tantalum
C2 = 1 µF Tantalum
MCP1525
Voltage Reference
Option 3
C1 = 0.1 µF
C2 = 1 µF to 10 µF
MCP1541
Voltage Reference
Option 3
C1 = 0.1 µF
C2 = 1 µF to 10 µF
TC59
LDO
Option 4
C1 = 1 µF Tantalum
C2 = 1 µF Tantalum
Power
Supply
LDO
R3
Test Point
From Function
Generator
Function
Generator
Output
Test
Point
SOT23 Evaluation Board PCB
C2
C
L