MC68HC05JJ6 Datasheet, PDF (122/216 Pages) Freescale Semiconductor, Inc – General Release Specification Microcontrollers

Analog Subsystem
Table 8-4. A/D Conversion Parameters
Name
Function
V_X
V_CAP
V_MAX
Unknown voltage on channel selection bus
Charging voltage on external capacitor
Maximum charging voltage on external capacitor
I_CHG
Charging current on external ramping capacitor
V_DD = 3 Vdc
V_DD = 5 Vdc
I_DIS Discharge current on external ramping capacitor
t_CHG
t_DIS
C_EXT
N
P
Time to charge external capacitor
(100 kHz < f_OSC < 4.0 MHz)
4-bit result
6-bit result
8-bit result
10-bit result
12-bit result
Time to discharge external capacitor, C_EXT
Capacitance of external ramping capacitor
Number of counts for I_CHG to charge C_EXT to V_X
Prescaler into timing function (÷ P)
Using core timer
Using 16-bit programmable timer
Using software loops
f_OSC Clock source frequency (excluding any prescaling)
Min
Typ
Max
V_SS
—
V_DD –1.5
V_SS
—
V_DD –1.5
—
—
V_DD –1.5
Refer to 13.10 Analog Subsystem
Characteristics (5.0 Vdc)
and 13.11 Analog Subsystem
Characteristics (3.0 Vdc)
Refer to 13.10 Analog Subsystem
Characteristics (5.0 Vdc)
and 13.11 Analog Subsystem
Characteristics (3.0 Vdc)
Units
V
V
v
µA
mA
0.032
0.128
0.512
2.048
8.192
—
0.0001
1
0.128
0.512
2.048
8.196
32.768
5
0.1
1024
2.56
10.24
40.96
120⁽¹⁾
120⁽¹⁾
10
2.0⁽²⁾
65536
ms
ms
ms
ms
ms
ms/µF
µF
counts
8
8
8
8
8
8
24
user defined user defined
Refer to 13.12 Control Timing (5.0 Vdc)
and 13.13 Control Timing (3.0 Vdc)
÷P
MHz
1. Limited by requirement for C_EXT to be less than 2.0 µF.
2. The desired type of capacitor for the ramp capacitor is any of the “poly” film types which have both low leakage and low dielec-
tric absorption (somtimes referred to as memory behavior). Low-cost monolithic ceramics are good for bypass use, but have
high dielectric absorption which makes them less desirable for an integration or storage application. Tantalum or aluminum
electrolytics have high dielectric absorption and too much leakage, as well. For integration or storage capacitors use capacitors
which have a dielectric absorption of less than 0.01%.
General Release Specification
122
Analog Subsystem
MC68HC05JJ6/MC68HC05JP6 — Rev. 3.2
Freescale Semiconductor