ADC1242 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – 12-Bit Plus Sign Sampling A/D Converter

February 1995
ADC1242
12-Bit Plus Sign Sampling A D Converter
General Description
The ADC1242 is a CMOS 12-bit plus sign successive ap-
proximation analog-to-digital converter On request the
ADC1242 goes through a self-calibration cycle that adjusts
positive linearity error to less than g1 LSB full-scale error to
less than g3 LSB and zero error to less than g2 LSB The
ADC1242 also has the ability to go through an Auto-Zero
cycle that corrects the zero error during every conversion
The analog input to the ADC1242 is tracked and held by the
internal circuitry and therefore does not require an external
sample-and-hold A unipolar analog input voltage range (0V
to a5V) or a bipolar range (b5V to a5V) can be accom-
modated with g5V supplies
The 13-bit word on the outputs of the ADC1242 gives a 2’s
complement representation of negative numbers The digi-
tal inputs and outputs are compatible with TTL or CMOS
logic levels
Applications
Y _{Digital Signal Processing}
Y _{High Resolution Process Control}
Y _{Instrumentation}
Key Specifications
Y _Resolution
12 Bits plus Sign
Y _{Conversion Time}
13 8 ms (max)
Y _{Linearity Error}
g1 LSB (g 0 0244%) (max)
Y _{Zero Error}
g2 LSB (max)
Y _{Positive Full Scale Error}
g3 LSB (max)
Y _{Power Consumption}
70 mW (max)
Features
Y _{Self-calibrating}
Y _{Internal sample-and-hold}
Y _{Bipolar input range with} g_{5V supplies and single}
a5V reference
Y _{No missing codes over temperature}
Y _{TTL MOS input output compatible}
Y _{Standard 28-pin ceramic DIP}
TRI-STATE is a registered trademark of National Semiconductor Corporation
Simplified Schematic
Connection Diagram
Dual-In-Line Package
C1995 National Semiconductor Corporation TL H 11735
Top View
TL H 11735 – 2
Order Number ADC1242CIJ
See NS Package Number J28A
TL H 11735 – 1
RRD-B30M115 Printed in U S A