CDP68HC68A2M96 INTERSIL [Intersil Corporation], CDP68HC68A2M96 Datasheet - Page 13

• Manufacturer Part Number: CDP68HC68A2M96
• Description: CMOS Serial 10-Bit A/D Converter
• Manufacturer: INTERSIL [Intersil Corporation]

The Internal Schmitt Oscillator
Figure 6 shows a simplified model of the Schmitt oscillator
used to help familiarize the user with its operation. Table 2
shows typical internal oscillator frequency versus
capacitance at 5V and 25
When measuring the oscillator, probe capacitance will affect
frequency. An alternative to direct frequency measurement
of the oscillator input is to measure the interval between
successive interrupts in modes 1 and 2.
OSCILLATOR
FIGURE 6. EQUIVALENT CIRCUIT FOR OSCILLATOR INPUT
TABLE 2. TYPICAL OSCILLATOR FREQUENCY vs
INPUT
C(pF)
118
18
38
48
68
EXTERNAL
CAP
330pF
CAPACITANCE AT V
OSC
D1
D2
0.26 - 0.75
0.65 - 2.0
0.54 - 1.6
0.38 - 1.1
1.0 - 3.0
V
V
f(MHz)
DD
SS
o
C.
13
NMOS
PMOS
Q3
Q4
DD
= 5V, T
C(pF)
1018
218
318
409
528
I1
200µA
I2
200µA
A
= 25
COMPARATOR
HYSTERESIS
o
0.148 - 0.40
0.111 - 0.25
0.107 - 0.23
0.072 - 0.17
0.040 - 0.10
N1
N2
C
f(MHz)
CONTROL
CONTROL
CDP68HC68A2