adc101c027cimkx National Semiconductor Corporation, adc101c027cimkx Datasheet - Page 15

• Manufacturer Part Number: adc101c027cimkx
• Description: I2c-compatible, 12-bit Analog-to-digital Converter Adc With Alert Function
• Manufacturer: National Semiconductor Corporation

1.3 ADC TRANSFER FUNCTION
The output format of the ADC101C021 is straight binary.
Code transitions occur midway between successive integer
LSB values. The LSB width for the ADC101C021 is V
The ideal transfer characteristic is shown in Figure 5. The
transition from an output code of 0000 0000 0000 to a code
of 0000 0000 0001 is at 1/2 LSB, or a voltage of V
Other code transitions occur at intervals of 1 LSB.
FIGURE 5. Ideal Transfer Characteristic
A
A
30052068
/ 2048.
/ 1024.
15
1.4 REFERENCE VOLTAGE
The ADC101C021 uses the supply (V
With that said, V
to-digital conversion will only be as precise as the reference
(V
is also recommended that the reference be driven by a volt-
age source with low output impedance.
The Applications section provides recommended ways to
drive the reference (V
details.
1.5 POWER-ON RESET
The power-on reset (POR) state is the point at which the sup-
ply voltage rises above the power-on reset threshold, gener-
ating an internal reset. Each of the registers contains a
defined value upon POR and this data remains there until any
of the following occurs:
•
•
•
When resetting the device, it is crutial that the V
lowered to a maximum of 200mV before the supply is raised
again to power-up the device. Dropping the supply to within
200mV of GND during a reset will ensure the ADC performs
as specified.
A
The first conversion is completed, causing the Conversion
Result Register and various status registers to be updated
internally.
The master writes a different data word to any of the
writeable registers.
The ADC is powered down.
). Therefore, the reference (V
A
must be treated as a reference. The analog-
A
) appropriately. Refer to Section 2.1 for
A
) should be free of noise. It
A
) as the reference.
www.national.com
A
supply be