TMS370C736AFNT Datasheet, PDF (44/49 Pages) Texas Instruments – 8-BIT MICROCONTROLLER

TMS370Cx36
8-BIT MICROCONTROLLER
SPNS039B – JANUARY 1996 – REVISED FEBRUARY 1997
ADC1 converter
The ADC1 converter has a separate power bus for its analog circuitry. These pins are referred to as V_CC3 and
V_SS3 . The purpose is to enhance ADC1 performance by preventing digital switching noise of the logic circuitry
that can be present on V_SS1 and V_CC1 from coupling into the ADC1 analog stage. All ADC1 specifications are
given with respect to V_SS3 unless otherwise noted.
Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-bits (256 values)
Monotonic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yes
Output conversion mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00h to FFh (00 for V_I ≤ V_SS3 ≤; FF for V_I ≤ V_ref)
Conversion time (excluding sample time) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 t_c
recommended operating conditions
MIN
VCC3 Analog supply voltage
4.5
VCC1–0.3
VSS3 Analog ground
Vref Non-VCC3 reference†
VSS1–0.3
2.5
Analog input for conversion
VSS3
† _{Vref must be stable, within ± 1/2 LSB of the required resolution, during the entire conversion time.}
NOM
5
VCC3
MAX
5.5
VCC1+0.3
VSS1+0.3
VCC3 + 0.1
Vref
UNIT
V
V
V
V
operating characteristics over recommended ranges operating conditions
PARAMETER
MIN MAX UNIT
Absolute accuracy‡
Differential/integral linearity error‡§
VCC3 = 5.5 V
VCC3 = 5.5 V
Vref = 5.1 V
Vref = 5.1 V
± 1.5 LSB
± 0.9 LSB
ICC3 Analog supply current
Converting
Nonconverting
2 mA
5 µA
II
Input current, AN0 – AN7
0 V ≤ VI ≤ 5.5 V
2 µA
Iref Input charge current
1 mA
Zref Source impedance of Vref
SYSCLK ≤ 3 MHz
3 MHz < SYSCLK ≤ 5 MHz
24 kΩ
10 kΩ
‡ _{Absolute resolution = 20 mV. At Vref = 5 V, this is one LSB. As Vref decreases, LSB size decreases; therefore, the absolute accuracy and}
differential/integral linearity errors in terms of LSBs increase.
§ _{Excluding quantization error of 1/2 LSB}
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