64
Analog Front End IC TMS37122 - Reference Guide August ’01
4.2.4.4 Trimming Capacitors and Switches
4.2.4.5 CLKA Watchdog Circuit
Parameter Sign Note Min Nom Max Unit
Trimming Steps Tstep 256
Min. Trimming Capacitor CT0 0
Trimming Capacitor 1 CT1 25 ºC 0.5 0.6 0.7 pF
Trimming Capacitor 2 CT2 25 ºC 1.0 1.2 1.4 pF
Trimming Capacitor 3 CT3 25 ºC 2.0 2.4 2.8 pF
Trimming Capacitor 4 CT4 25 ºC 4.0 4.7 5.4 pF
Trimming Capacitor 5 CT5 25 ºC 8.0 9.4 10.8 pF
Trimming Capacitor 6 CT6 25 ºC 16 18.8 21.6 pF
Trimming Capacitor 7 CT7 25 ºC 32 37.6 43.2 pF
Trimming Capacitor 8 CT8 25 ºC 64 75.3 86.6 pF
Max. Trimming Capacitor
(CT = CT1+CT2....+CT8)
CT 25 ºC
127.5
-15
150
0
172.5
+15
pF
%
Voltage Coefficient of CT dCT/dV 0.1 pF/V
Temp. Coefficient of CT dCT/dT 0.02 pF/K
'On' Res. Trim Switch 1 RT1 VPP = 16 V 800 Ω
'On' Res. Trim Switch 2 RT2 VPP = 16 V 400 Ω
'On' Res. Trim Switch 3 RT3 VPP = 16 V 400 Ω
'On' Res. Trim Switch 4 RT4 VPP = 16 V 200 Ω
'On' Res. Trim Switch 5 RT5 VPP = 16 V 200 Ω
'On' Res. Trim Switch 6 RT6 VPP = 16 V 100 Ω
'On' Res. Trim Switch 7 RT7 VPP = 16 V 50 Ω
'On' Res. Trim Switch 8 RT8 VPP = 16 V 28.0 Ω
'Off' Res. Trim S. 1 ... 8 RT1..8 VPP = 16 V 1 ΜΩ
Parameter Sign Note Min Nom Max Unit
CLKA Watchdog Time twdg VBAT = 2 ...4 V 500 800 2600 µs