Appendix A - Specifications [U6 Datasheet]

Parameter

Conditions

Min

Typical

Max

Units

General

USB Cable Length

5

meters

Supply Voltage (1)

4.75

5

5.25

volts

Supply Current (2)

100

mA

Operating Temperature

-40

85

°C

Clock Error

~ 25 °C

±30

ppm

-10 to 60 °C

±50

ppm

-40 to 85 °C

±100

ppm

Typ. Command Execution Time (3)

USB High-High

0.6

ms

USB Other

4

ms

Vs Outputs

Typical Voltage (4)

Self-Powered

4.75

5

5.25

volts

Bus-Powered

4.8

5

5.25

Maximum Current (4)

Self-Powered

400

mA

Bus-Powered

0

mA

Vm+/Vm- Outputs

Typical Voltage

No-load

±13

volts

@ 2.5 mA

±12

volts

Maximum Current

2.5

mA

10UA & 200UA Current Outputs

Absolute Accuracy (5)

~ 25 °C

±0.1

±0.2

%

Temperature Coefficient

See Section 2.5

ppm/°C

Maximum Voltage

VS - 2.0

volts

(1) Device should operate down to about 3.5 volts, with the following considerations. The hi-res converter on the U6-Pro is not specified for operation below 4.75 volts. The voltage drive capability of the current sources will be reduced. The maximum output of the DACs will be limited by VS. The input range of the analog inputs will be reduced approximately 3 volts for each 1 volt that VS is below 4.5 volts.     

(2) Typical current drawn by the U6 itself, not including any user connections     

(3) Total typical time to execute a single Feedback function with no analog inputs. Measured by timing a Windows application that performs 1000 calls to the Feedback function. See Section 3.1 for more timing information     

(4) These specifications are related to the power provided by the host/hub. Self- and bus-powered describes the host/hub. not the U6. Self-powered would apply to USB hubs with a power supply, all known desktop computer USB hosts, and some notebook computer USB hosts. And example of bus powered would be a hub with no power supply, or many PDA ports. The current rating is the maximum current that should be sourced through the U6 and out of the Vs terminals     

(5) This is compared to the value stored during factory calibration     

Parameter

Conditions

Min

Typical

Max

Units

Analog Inputs

Typical Input Range (6)

Gain=1

-10.6

10.1

volts

Gain=10

-1.06

1.01

volts

Gain=100

-0.106

0.101

volts

Gain=1000

-0.0106

0.0101

volts

Max AIN Voltage to GND (7)

Valid Readings

-11.5

11.5

volts

Max AIN Voltage to GND (8)

No Damage

-20

20

volts

Input Bias Current (9)

20

nA

Input Impedance (9)

1

GΩ

Source Impedance (9)

1

kΩ

Integral Linearity Error

Range=±10, ±1, ±0.1

±0.01

% FS

Range=±0.01

±0.1

% FS

Absolute Accuracy

Range=±10, ±1, ±0.1

±0.01

% FS

Range=±10

±2000

μV

Range=±1

±200

μV

Range=±0.1

±20

μV

Range=±0.01

±0.1

% FS

Range=±0.01

±20

μV

Temperature Drift

15

ppm/°C

Channel Crosstalk (10)

< 1kHz

-100

dB

1kHz - 50kHz

20

dB/dec

Noise (Peak-To-Peak)

See Appendix B

<1

μV

Effective Resolution (RMS)

See Appendix B

22

bits

Noise-Free Resolution

See Appendix B

20

bits

Command/Response Speed

See Section 3.1

Stream Performance

See Section 3.2

(6) Differential or single-ended     

(7) This is the maximum voltage on any AIN pin compared to ground for valid measurements on that channel. For single-ended readings on the channel itself, inputs are limited by the "Typical Input Range" above, and for differential readings consult the signal range tables in Section 2.6.5. Further, if a channel has over 13.0 volts compared to ground, readings on other channels could be affected. Because all even channels are on 1 front-end mux, and all odd channels on a 2nd front-end mux, an overvoltage (>13V) on a single channel will generally affect only even or only odd channels.     

(8) Maximum voltage, compared to ground, to avoid damage to the device. Protection level is the same whether the device is powered or not.  This spec is continuous.  The device can handle brief transients with much higher voltages (e.g. ESD). 

(9) The key specification here is the maximum source impedance. As long as the source impedance is not over this value, there will be no substantial errors due to impedance problems. For source impedance greater than this value, there are two error sources that need to be considered. First, there is a simple offset error due to the input bias current flowing through the source impedance. Second, if sampling more than 1 channel, there can be a more complex settling error if the analog input system needs to quickly swing from one voltage to another. Required settling time to meet specifications can depend on the source impedance of the signal, channel order, resolution index, and gain/range.     

(10) Typical crosstalk on a grounded AIN pin, with 20Vpp sine wave on
adjacent AIN pin. An adjacent AIN pin refers to multiplexer channel
location not channel number, e.g. AIN0-AIN2 or AIN1-AIN3 pairs.     

Parameter

Conditions

Min

Typical

Max

Units

Analog Outputs (DAC)

Nominal Output Range (11)

No Load

0.04

4.95

volts

@ ±2.5 mA

0.255

4.775

volts

Resolution

12

bits

Absolute Accuracy

5% to 95% FS

±0.1

% FS

Integral Linearity Error

±0.35

±1

counts

Differential Linearity Error

±0.1

±0.5

counts

Error Due To Loading

@ 100 µA

0.1

%

@ 1 mA

1

%

Source Impedance

50

Ω

Short Circuit Current (12)

Max to GND

50

mA

Time Constant

300

μs

Digital I/O, Timers, Counters

Low Level Input Voltage

-0.3

0.8

volts

High Level Input Voltage

2

5.8

volts

Maximum Input Voltage (13)

FIO

-10

10

volts

EIO/CIO/MIO

-6

6

volts

Output Low Voltage (14)

No Load

0

volts

--- FIO

Sinking 1 mA

0.55

volts

--- EIO/CIO/MIO

Sinking 1 mA

0.18

volts

--- EIO/CIO/MIO

Sinking 5 mA

0.9

volts

Output High Voltage (14)

No Load

3.3

volts

--- FIO

Sourcing 1 mA

2.75

volts

--- EIO/CIO/MIO

Sourcing 1 mA

3.12

volts

--- EIO/CIO/MIO

Sourcing 5 mA

2.4

volts

Short Circut Current (14)

FIO

6

mA

EIO/CIO/MIO

16

mA

Output Impedance (14)

FIO

550

Ω

EIO/CIO/MIO

180

Ω

Counter Input Frequency (15)

8

MHz

Input Timer Total Edge Rate (16)

No Stream

30000

edges/s

While Streaming

7000

edges/s

(11) Maximum and minimum analog output voltage is limited by the supply voltages (Vs and GND). The specifications assume Vs is 5.0 volts. Also, the ability of the DAC output buffer to driver voltages close to the power rails, decreases with increasing output current, but in most applications the output is not sinking/source much current as the output voltage approaches GND.     

(12) Continuous short circuit will not cause damage.     

(13) Maximum voltage to avoid damage to the device. Protection works whether the device is powered or not, but continuous voltages over 5.8 volts or less than -0.3 volts are not recommended when the U3 is unpowered, as the voltage will attempt to supply operating power to the U3 possibly causing poor start-up behavior.     

(14) These specifications provide the answer to the question. "How much current can the digital I/O sink or source?". For instance, if EIO0 is configured as output-high and shorted to ground, the current sourced by EIO0 into ground will be about 16 mA (3.3/180). If connected to a load that draws 5 mA, EIO0 can provide that current but the voltage will droop to about 2.4 volts instead of the nominal 3.3 volts. If connected to a 180 ohm load to ground, the resulting voltage and current will be about 1.65 volts @ 9 mA.     

(15) Hardware counters. 0 to 3.3 volt square wave.     

(16) To Avoid missing edges, keep the total number of applicable edges on all applicable timers below this limit. See Section 2.9 for more information.