ICL7104
ICL7104 with ICL8052/8068 Integrating A/D Converter Equations
• Oscillator
CRYSTAL or RC (RC on -14 Part Only)
f
f
C
(Typ) 200kHz
= 0.45/RC (ICL7104-14 Only)
> 50pF and R
OSC
OSC
V
IN
Count = 32768 × -------------- (7104-16)
> 50K
V
OSC
• Oscillator Period
= 1/f
OSC
REF
t
OSC
OSC
• Integration Clock Frequency
= f
V++ = +15V
V- = -15V
V+ = +5V
f
CLOCK
OSC
• Integration Period
V
≅ 1.75V
REF
If V
t
t
= 8192 x t
(7104-14)
INT
INT
OSC
= 32768 x t
not used, float output pin.
REF
(7104-16)
OSC
• Auto Zero Capacitor Values
• 60/50Hz Rejection Criterion
/t or t /t = Integer
0.01µF < C < 1µF
AZ
t
INT 60Hz INT 50Hz
• Reference Capacitor Value
• Optimum Integration Current
= 20µA
• C
= (Buffer Gain) x C
AZ
I
REF
INT
• Full Scale Analog Input Voltage
V
(Typ) = 200mV to 2V = 2V
REF
INFS
• Integrate Resistor
(BufferGain) × V
INFS
= ------------------------------------------------------------
R
INT
I
INT
• Integrate Capacitor
(t
)(I
)
INT INT
V
C
= -------------------------------
INT
INT
• Integrator Output Voltage
(t
)(I
)
INT INT
C
V
= -------------------------------
INT
INT
V
(Typ) = 9V
INT
• Output Count
V
IN
Count = 8192 × -------------- (7104-14)
V
REF
• Output Type:
Binary Amplitude with Polarity and Overrange Bits.
• Power Supply: ±15V, +5V
19
ETC [ ETC ]
