Datasheet LTC1283 (Analog Devices) - 10

LTC1283
O U U W U APPLICATI S I FOR ATIO Unipolar/Bipolar (UNI)
The fifth input bit (UNI) determines whether the conver- input voltage. When UNI is a logical zero, a bipolar conver- sion will be unipolar or bipolar. When UNI is a logical one, sion will result. The input span and code assignment for a unipolar conversion will be performed on the selected each conversion type are shown in the figures below.
Unipolar Transfer Curve (UNI = 1) Unipolar Output Code (UNI = 1)
1 1 1 1 1 1 1 1 1 1
INPUT VOLTAGE
1 1 1 1 1 1 1 1 1 0
OUTPUT CODE INPUT VOLTAGE (VREF = 2.5V)
• • 1 1 1 1 1 1 1 1 1 1 VREF – 1LSB 2.4976V 1 1 1 1 1 1 1 1 1 0 V • REF – 2LSB 2.4951V • • • • • 0 0 0 0 0 0 0 0 0 1 • VIN • • • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1LSB 0.0024V 0V 1LSB VREF – 2LSB VREF 0 0 0 0 0 0 0 0 0 0 0V 0V VREF – 1LSB LTC1283 AI06 LTC1283 AI04
Bipolar Transfer Curve (UNI = 0)
0 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 0 1LSB –VREF + 1LSB 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 –VREF VIN 1 1 1 1 1 1 1 1 1 1 VREF – 2LSB VREF 1 1 1 1 1 1 1 1 1 0 VREF – 1LSB –1LSB –2LSB 1 0 0 0 0 0 0 0 0 1 LTC1283 AI05 1 0 0 0 0 0 0 0 0 0
Bipolar Output Code (UNI = 0) INPUT VOLTAGE OUTPUT CODE INPUT VOLTAGE (VREF = 2.5V)
0 1 1 1 1 1 1 1 1 1 VREF – 1LSB 2.4951V 0 1 1 1 1 1 1 1 1 0 VREF – 2LSB 2.4902V • • • • • • • • • 0 0 0 0 0 0 0 0 0 1 1LSB 0.0049V 0 0 0 0 0 0 0 0 0 0 0V 0V 1 1 1 1 1 1 1 1 1 1 –1LSB – 0.0049V 1 1 1 1 1 1 1 1 1 0 –2LSB – 0.0098V • • • • • • • • • 1 0 0 0 0 0 0 0 0 1 –(VREF) + 1LSB –2.4951V 1 0 0 0 0 0 0 0 0 0 – (VREF) –2.5000V LTC1283 AI07 1283fb 10