ICL71C03 Datasheet, PDF (19/19 Pages) Intersil Corporation – Precision 4 1/2 Digit, A/D Converter

ICL8052/ICL71C03, ICL8068/ICL71C03
ICL71C03 with ICL8052/8068 Integrating A/D Converter Equations
The ICL71C03 does not have an internal crystal or RC
oscillator. It has a clock input only.
Integration Period
t_INT = _f-¹-_C---⁰--_L-^,--_O-⁰---_C-⁰---⁰-_K-- (4-1/2 Digit)
t_INT = -_f-_C-¹---^,-_L--⁰-_O---⁰-_C--⁰---_K-- (3-1/2 Digit)
Integration Clock Period
t_CLOCK = 1/f_CLOCK
60/50Hz Rejection Criterion
t_INT/t_60Hz or t_INT/t_50Hz = Integer
Optimum Integration Current
I_INT = 20µA
Full Scale Analog Input Voltage
V_INFS (Typ) = 200mV to 2.0V = 2V_REF
Integrate Resistor
R_INT = -⁽--^B----^u----^f--^f--^e----^r---^G----_I-^a-_I-_N--ⁱ--ⁿ-_T--⁾----^×-----^V----^I--^N----^F----^S--
Integrate Capacitor
C_INT
=
(_---t_{--I--N----T----})_--(_--I_{--I--N----T----})
V_INT
Integrator Output Voltage
V_INT = ⁽---^t--^I--^N---_C-^T---_I-⁾-_N-⁽--^I--_TI--^N----^T----⁾
V_INT (Typ) = 9V
Output Count
Count = 10, 000 × _V---^V--_R---^I-_EN----_F- (4-1/2 Digit)
Count = 1, 000 × _V---^V--_R---^I-_EN----_F- (3-1/2 Digit)
NOTE: The 4¹/₂ digit mode’s LSD will be output as a zero in the 3¹/₂
digit mode.
Output Type:
4 Nibbles BCD with Polarity and Over-range.
Power Supply: ±15V, +5V
V++ = +15V
V- = -15V
V+ = +5V
V_REF ≅ 1.75V
If V_REF not used, float output pin.
Auto Zero Capacitor Values
0.01µF < C_AZ < 1µF
Reference Capacitor Value
C_REF = (Buffer Gain) x C_AZ
AUTO ZERO
(COUNTS)
30,001 - 10,001
3,001 - 1,001
INTEGRATE
(FIXED COUNT)
10,000
1,000
DEINTEGRATE
(COUNTS)
1 - 20,001
1 - 2,001
TOTAL CONVERSION TIME (t_CONV)
(IN CONTINUOUS MODE)
t_CONV = 40,002 * t_CLOCK (4¹/₂ DIGIT MODE)
t_CONV = 4,002 * t_CLOCK (3¹/₂ DIGIT MODE)
FIGURE 20. INTEGRATOR OUTPUT
(4¹/₂ DIGIT)
(3¹/₂ DIGIT)
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