Linear Technology DC1793A Demo Manual page 3

QUICK START PROCEDURE
Figure 2. Measuring Input or Output Ripple
80
V = 12V, CONSTANT FREQUENCY
IN
+LDO DISABLED
75
–LDO = –5V, 0A
70
50kHz CF MODE
65
60
55
50
45
40
35
30
25
20
15
10
1
dc1793a F02
200kHz CF MODE
500kHz CF MODE
Figure 4. V to V Constant-Frequency Mode Operation Efficiency
IN OUT
DEMO MANUAL DC1793A
+
V
LDO
10mV/DIV
AC-COUPLED
–
V
LDO
10mV/DIV
AC-COUPLED
V
OUT
10mV/DIV
AC-COUPLED
V = 15V f
IN OSC
+
V = 12V I
LDO LDO
–
V = –12V I
LDO LDO
Figure 3. LDO Rejection of V
10
–I (mA)
VOUT
1μs/DIV
= 500kHz
+
= 50mA
–
–50mA
Ripple
OUT
100
dc1793a F04
dc1793a F03
dc1793afa
3