AC164112 Microchip Technology, AC164112 Datasheet - Page 106

• Manufacturer Part Number: AC164112
• Description: VOLTAGE LIMITER MPLAB ICD2 VPP
• Manufacturer: Microchip Technology

Specifications of AC164112

• Accessory Type: Voltage Limiter
• Product: Cable Assemblies
• Features: Programming And Debugging The Latest PIC12/PIC16/PIC18 Products
• Development Tool Type: Hardware - Eval/Demo Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: MPLAB®
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With: MPLAB ICD 2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PIC16F72X/PIC16LF72X
9.3
For the ADC to meet its specified accuracy, the charge
holding capacitor (C
charge to the input channel voltage level. The Analog
Input model is shown in Figure 9-3. The source imped-
ance (R
impedance directly affect the time required to charge
the capacitor C
impedance varies over the device voltage (V
to Figure 9-3. The maximum recommended imped-
ance for analog sources is 10 kΩ. As the source
EQUATION 9-1:
DS41341E-page 106
The value for T
Solving for T
Therefore:
Note 1: The reference voltage (V
Assumptions:
V
V
V
Note: Where n = number of bits of the ADC.
S
2: The charge holding capacitor (C
3: The maximum recommended impedance for analog sources is 10 kΩ. This is required to meet the pin
A/D Acquisition Requirements
) and the internal sampling switch (R
AP P LI ED
AP P LI ED
AP P LI ED
T
leakage specification.
ACQ
T
C
ACQ
T
:
HOLD
C
C
⎛
⎝
⎛
⎜
⎝
⎛
⎜
⎝
=
Temperature
can be approximated with the following equations:
=
=
=
=
1
1 e
1 e
HOLD
=
=
=
. The sampling switch (R
2
ACQUISITION TIME EXAMPLE
4.42
–
–
–
1.12
–
–
ΜS
Amplifier Settling Time
T
2µs
C
10pF 1k
--------------------------
(
AMP
) must be allowed to fully
2
–
--------- -
–
-------- -
HOLD
RC
+
RC
ΜS
µs
T
Tc
n
+
C
1.12
+
⎞
⎟
⎠
⎞
⎟
⎠
(
+
1
T
1
(
C
) 1
=
R
=
T
ΜS
Ω
+
IC
C
–
=
V
V
+
+
[
+
REF
+
(
A PP LIE D
⎞
⎠
CHOLD
7k
50°C and external impedance of 10k
Temperature - 25°C
T
[
R
(
) has no effect on the equation, since it cancels itself out.
COFF
Ω
50°C- 25°C
=
SS
+
+
HOLD
DD
V
10k
CHOLD
R
), refer
⎛
⎝
S
1
+
) ln(1/511)
) is not discharged after each conversion.
Ω
SS
SS
–
Hold Capacitor Charging Time
)
)
)
) 0.05
--------------------------
(
ln(0.001957)
(
2
n
+
) 0.05µs/°C
1
ΜS
1
(
) 1
/°C
impedance is decreased, the acquisition time may be
decreased. After the analog input channel is selected
(or changed), an A/D acquisition must be done before
the conversion can be started. To calculate the mini-
mum acquisition time, Equation 9-1 may be used. This
equation assumes that 1/2 LSb error is used (256 steps
for the ADC). The 1/2 LSb error is the maximum error
allowed for the ADC to meet its specified resolution.
–
)
⎞
⎠
]
;[1] V
;[2] V
;combining [1] and [2]
)
]
Ω
CHOLD
CHOLD
5.0V V
+
charged to within 1/2 lsb
charge response to V
DD
Temperature Coefficient
© 2009 Microchip Technology Inc.
APPLIED