FAN50FC3 Datasheet, PDF (9/21 Pages) Fairchild Semiconductor – 8-Bit Programmable, 2- to 3-Phase FastvCore™ Buck Controller

Test Diagrams
12 V
1.25 V
20k
100nF
VCC
VIDSEL
EN
CSCOMP
CSSUM
CSREF
250k
1k
10nF
10nF
FB
COMP
ILIMIT
SS
DELAY
GND
FBRTN
VID0
VID1
VID2
VID3
VID4
VID5
VID6
VID7
SW1
SW2
SW3
8 _{8 Bit}
Code
12 V
VCC
23
100nF
13 ^CSCOMP
39k
1k
+
V 1V
-
CSSUM
12
CSREF
11
-
CSA
+
GND
14
Figure 3. Closed-Loop Output Voltage Accuracy
Figure 4. Current-Sense Amplifier V_OS
12 V
23 VCC
10k
5 COMP
4 FB
-
dV V
+
+
VV
-
13 CSCOMP
11 CSREF
14 GND
Figure 5. Droop Voltage Accuracy
Rt as a function of Oscillator Frequency
1000
100
10
0
1000
2000
3000
Oscillator Frequency (kHz)
4000
Figure 6. R_T Required to Set Oscillator Frequency
5000
© 2007 Fairchild Semiconductor Corporation
FAN50FC3 Rev. 1.0.0
9 of 21
www.fairchildsemi.com