TC850CPL Microchip Technology, TC850CPL Datasheet - Page 15

• Manufacturer Part Number: TC850CPL
• Description: IC ADC 15BIT FAST 40DIP
• Manufacturer: Microchip Technology

Specifications of TC850CPL

• Data Interface: Parallel
• Number Of Bits: 15
• Sampling Rate (per Second): 40
• Number Of Converters: 1
• Voltage Supply Source: Dual ±
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 40-DIP (0.600", 15.24mm)
• Resolution (bits): 15bit
• Sampling Rate: 40SPS
• Input Channel Type: Differential
• Supply Voltage Range - Analog: ± 5V
• Supply Current: 2mA
• Digital Ic Case Style: DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

7.0
7.1
7.1.1
The typical value for reference voltage V
1.6384V. This value yields a full scale voltage of
3.2768V and resolution of 100 μV per step. The V
value is derived by dividing V
V
value should be adjusted within ±1% to maintain 15-bit
accuracy for the total conversion process;
EQUATION 7-1:
however, because the TC850 performs a ratiometric
conversion. Therefore, the conversion result will be:
EQUATION 7-2:
The full scale voltage can range from 3.2V to 3.5V. Full
scale voltages of less than 3.2V will result in increased
noise in the Least Significant bits, while a full scale
above 3.5V will exceed the input common-mode range.
7.1.2
The TC850 buffer supplies 25 μA of integrator charging
current with minimal linearity error. R
calculated:
EQUATION 7-3:
For a full scale voltage of 3.2768V, values of R
between 120 kΩ and 150 kΩ are acceptable.
© 2006 Microchip Technology Inc.
The reference voltage is not limited to exactly 1.6384V,
REF2
Digital Counts =
value is 1.6384V/64, or 25.6 mV. The V
ANALOG SECTION TYPICAL
APPLICATIONS
Component Selection
REFERENCE VOLTAGE
INTEGRATION RESISTOR
V
R
REF
INT
=
=
:
V
V
REF1
V
V
FULLSCALE
REF1
IN
64
25 μA
REF1
± 1%
• 16384
by 64. Thus, typical
INT
is easily
REF1
INT
REF2
REF2
is
7.1.3
The integration capacitor should be selected to
produce an integrator swing of ≈ 4V at full scale. The
capacitor value is easily calculated:
EQUATION 7-4:
The integration capacitor should be selected for low
dielectric absorption to prevent rollover errors. A
polypropylene, polyester or polycarbonate dielectric
capacitor is recommended.
7.1.4
The reference capacitors require a low-leakage dielec-
tric, such as polypropylene, polyester or polycarbon-
ate. A value of 1 μF is recommended for operation over
the temperature range. If high-temperature operation is
not required, the C
7.1.5
Five capacitors are required to auto-zero the input
buffer, integrator amplifier and comparator. Recom-
mended capacitors are 0.1 μF film dielectric (such as
polyester or polypropylene). Ceramic capacitors are
not recommended.
where:
F
frequency and V
CLOCK
is the crystal or external oscillator
INTEGRATION CAPACITOR
REFERENCE CAPACITORS
AUTO-ZERO CAPACITORS
C =
REF
R
V
FS
INT
FS
is the maximum input voltage.
values can be reduced.
•
4V F
4 • 256
CLOCK
DS21479C-page 15
TC850