Measurement Computing USB-1208LS - Manual (Page 19)

19
Chapter 4
Specifications
All specifications are subject to change without notice.
Typical for 25°C unless otherwise specified.
Specifications in italic text are guaranteed by design.
Analog input
Table 1. Analog input specifications
Parameter Conditions Specification
A/D converter type Successive approximation type
Input voltage range for linear operation,
single-ended mode CHx to GND ±10 V max
Input common-mode voltage range for linear
operation, differential mode CHx to GND –10 V min, +20 V max
Absolute maximum input voltage CHx to GND ±40V max
Input current (Note 1) Vin = +10 V 70µA typ
Vin = 0V –12µA typ
Vin = –10 V –94µA typ
Input impedance 122 kΩ
Number of channels 8 single ended / 4 differential, software
selectable
Input ranges Single-ended mode ±10V, G=2
Differential mode ±20V, G=1
±10V, G=2
±5V, G=4
±4V, G=5
±2.5V, G=8
±2.0V, G=10
±1.25V, G=16
±1.0V, G=20
Software selectable
Throughput Software paced 50 S/s
Hardware paced 1.2 kS/s
Burst scan to 4 K sample
FIFO 8 kS/s
Channel gain queue Up to 8 elements Software configurable channel, range, and
gain.
Resolution (Note 2) Differential 12 bits, no missing codes
Single ended 11 bits
CAL accuracy CAL = 2.5V ±0.05% typ, ±0.25% max
Integral linearity error ±1 LSB typ
Differential linearity error ±0.5 LSB typ
Repeatability ±1 LSB typ
CAL current Source 5 mA max
Sink 20 µA min, 200 nA typ
Trigger Source Software selectable External digital: TRIG_IN
Note 1: Input current is a function of applied voltage on the analog input channels. For a given input voltage,
Vin, the input leakage is approximately equal to (8.181*Vin – 12) µA.
Note 2: The AD7870 converter only returns 11-bits (0 to 2,047 codes) in single-ended mode.