Z86D99 ZILOG [Zilog, Inc.], Z86D99 Datasheet - Page 37

• Manufacturer Part Number: Z86D99
• Description: Low-Voltage Micro controllers with ADC
• Manufacturer: ZILOG [Zilog, Inc.]

PS003807-1002
Figure 15. Low-Pass Filter (with 8-MHz Crystal)
The sampling frequency of the modulator f
f
dissipated in the ADC block.
The ADC can be enabled or disabled. When enabled, the
input voltage. When switching between the channels (step response), the
required time to reach the final value is given by the time constant of the low-pass
filter:
When available, the reference for the ADC is set externally with the V
pins. The output code represents the following ratio:
SCLK
10
12
14
16
18
20
2
4
6
8
0
0
/2 (bit1 from ADCCTRL). Reducing the clock frequency lowers the power
0.5
T
delay
1
P
D
out
R
=
1.5
-------- -
f
=
E
3db
2
------------------------------ -
V
V
L
Ref+
=
in
2
I
--------------------------- -
0.0021f
–
Filter response
–
V
M
V
log10(f)
Ref-
Z86D990/Z86D991 OTP and Z86L99X ROM
Ref-
2.5
2
I
Low-Voltage Microcontrollers with ADC
ADC
N
ADC
256
3
A
=
can be selected between f
---------- -
f
R
952
ADC
3.5
Y
4
converter tracks the
4.5
ref+
5
SCLK
and V
and
ref-
30