Measurement Computing USB-3103 User manual

USB-3103
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User's Guide
FA .  MEASUREMENT
  COMPUTING™

USB-3103
USB-based Analog Output
User Guide
Document Revision 3A, March, 2009
© Copyright 2009, Measurement Computing Corporation

3
HM USB-3103.doc
Trademark and Copyright Information
Measurement Computing Corporation, InstaCal, Universal Library, and the Measurement Computing logo are
either trademarks or registered trademarks of MeasurementComputing Corporation. Refer to the Copyrights &
Trademarks section on mccdaq.com/legal for more information about Measurement Computing trademarks.
Other product and company namesmentioned herein are trademarks or trade names of their respective
companies.
©2009 MeasurementComputingCorporation. All rights reserved. No part of this publicationmay be
reproduced, stored in a retrieval system, or transmitted, in any form by any means, electronic,mechanical, by
photocopying, recording, or otherwise without the prior written permission of Measurement Computing
Corporation.
Notice
Measurement Computing Corporation does not authorize any Measurement Computing Corporation product for
use in life support systems and/or devices without prior written consent from Measurement Computing
Corporation. Life support devices/systems are devices or systems that, a) are intended for surgical implantation
into the body, or b) support or sustain life and whose failure to perform can be reasonably expected to result in
injury. Measurement Computing Corporation products are not designed with the components required, and are
not subject to the testing required to ensure a level of reliability suitable for the treatment and diagnosis of
people.

4
Trademark and Copyright Information
TracerDAQ, Universal Library, Measurement Computing Corporation, and the Measurement Computing logo are either
trademarks or registered trademarks of Measurement Computing Corporation.
Windows, Microsoft, and Visual Studio are either trademarks or registered trademarks of Microsoft Corporation
LabVIEW is a trademark of National Instruments.
CompactFlash is a registered trademark of SanDisk Corporation.
XBee and XBee-PRO are trademarks of MaxStream, Inc.
All other trademarks are the property of their respective owners.
Information furnished by Measurement Computing Corporation is believed to be accurate and reliable. However, no
responsibility is assumed by Measurement Computing Corporation neither for its use; nor for any infringements of patents or
other rights of third parties, which may result from its use. No license is granted by implication or otherwise under any patent or
copyrights of Measurement Computing Corporation.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form by
any means, electronic, mechanical, by photocopying, recording, or otherwise without the prior written permission of
Measurement Computing Corporation.
Notice
Measurement Computing Corporation does not authorize any Measurement Computing Corporation product for use
in life support systems and/or devices without prior written consent from Measurement Computing Corporation.
Life support devices/systems are devices or systems which, a) are intended for surgical implantation into the body,
or b) support or sustain life and whose failure to perform can be reasonably expected to result in injury.
Measurement Computing Corporation products are not designed with the components required, and are not subject
to the testing required to ensure a level of reliability suitable for the treatment and diagnosis of people.

5
Table of Contents
Preface
About this User's Guide.......................................................................................................................7
What you will learn from this user's guide.........................................................................................................7
Conventions in this user's guide........................................................................................................................................ 7
Where to find more information.........................................................................................................................7
Chapter 1
Introducing the USB-3103....................................................................................................................8
Overview: USB-3103 features ...........................................................................................................................8
USB-3103 block diagram...................................................................................................................................9
Software features................................................................................................................................................9
Chapter 2
Installing the USB-3103......................................................................................................................10
What comes with your USB-3103 shipment? ..................................................................................................10
Hardware .........................................................................................................................................................................10
Additional documentation................................................................................................................................................10
Unpacking the USB-3103.................................................................................................................................10
Installing the software ......................................................................................................................................11
Installing the hardware .....................................................................................................................................11
Connecting the USB-3103 to your system.......................................................................................................................11
Calibrating the USB-3103................................................................................................................................12
Chapter 3
Functional Details...............................................................................................................................13
External components ........................................................................................................................................13
USB connector.................................................................................................................................................................13
Status LED.......................................................................................................................................................................13
Power LED ......................................................................................................................................................................13
Screw terminal banks.......................................................................................................................................................14
Analog voltage output terminals (VOUT0 to VOUT7) ...................................................................................................15
Digital I/O terminals (DIO0 to DIO7) .............................................................................................................................15
Digital I/O control terminal (DIO CTL) for pull-up/down configuration........................................................................16
Ground terminals (AGND, DGND).................................................................................................................................16
Synchronous DAC load terminal (SYNCLD)..................................................................................................................16
Counter terminal (CTR)...................................................................................................................................................16
Power terminal (+5V)......................................................................................................................................................16
Synchronizing multiple units............................................................................................................................17
Chapter 4
Specifications......................................................................................................................................18
Analog voltage output ......................................................................................................................................18
Analog output calibration.................................................................................................................................19
Digital input/output ..........................................................................................................................................19
Synchronous DAC Load...................................................................................................................................20
Counter.............................................................................................................................................................20
Memory ............................................................................................................................................................21
Microcontroller.................................................................................................................................................21
Power................................................................................................................................................................21
USB specifications ...........................................................................................................................................21
Environmental ..................................................................................................................................................22

USB-3103 User's Guide
6
Mechanical .......................................................................................................................................................22
Main connector and pin out..............................................................................................................................22
Declaration of Conformity..................................................................................................................23

7
Preface
About this User’s Guide
What you will learn from this user's guide
This user's guide describes the Measurement Computing CIO-DDA06/Jr/16 data acquisition board
and lists hardware specifications.
Conventions in this user's guide
For more information
Text presented in a box signifies additional information related to the subject matter.
Caution! Shaded caution statements present information to help you avoid injuring yourself and others,
damaging your hardware, or losing your data.
bold text Bold text is used for the names of objects on a screen, such as buttons, text boxes, and check boxes.
italic text Italic text is used for the names of manuals and help topic titles, and to emphasize a word or phrase.
Where to find more information
Additional information about CIO-DDA06/Jr/16 hardware is available on our website at
www.mccdaq.com.You can also contact Measurement Computing Corporation with specific questions.
Knowledgebase: kb.mccdaq.com
Tech support form: www.mccdaq.com/support/support_form.aspx
Email: [e-mail]
Phone: [phone] and follow the instructions for reaching Tech Support
For international customers, contact your local distributor. Refer to the International Distributors section on our
website at www.mccdaq.com/International.

8
Chapter 1
Introducing the USB-3103
Overview: USB-3103 features
This user's guide contains all of the information you need to connect the USB-3103 to your computer and to the
signals you want to control. The USB-3103 is part of the Measurement Computing brand of USB-based data
acquisition products.
The USB-3103 is a USB 2.0 full-speed device that is supported under popular Microsoft®Windows®operating
systems. The USB-3103 is fully compatible with both USB 1.1 and USB 2.0 ports.
The USB-3103 provides eight channels of analog voltage output, eight digital I/O connections, and one 32-bit
event counter.
The USB-3103 has two quad (4-channel) 16-bit digital-to-analog converters (DAC). You set the voltage output
range of each DAC channel independently with software for either bipolar or unipolar. The bipolar range is
±10 V, and the unipolar range is 0 to 10 V. The analog outputs may be updated individually or simultaneously.
A bidirectional synchronization connection allows you to simultaneously update the DAC outputs on multiple
devices.
The USB-3103 features eight bidirectional digital I/O connections. You can configure the DIO lines as input or
output in one 8-bit port. All digital pins are floating by default. A screw terminal connection is provided for
pull-up (+5 V) or pull-down (0 volts) configuration.
The 32-bit counter can count TTL pulses.
The USB-3103 is powered by the +5 volt USB supply from your computer. No external power is required. All
I/O connections are made to the screw terminals located along each side of the USB-3103.
Figure 1. USB-3103

USB-3103 User's Guide Introducing the USB-3103
9
USB-3103 block diagram
USB-3103 functions are illustrated in the block diagram shown here.
Screw terminal I/O connector
USB
Microcontroller
Screw terminal I/O connector
8
Event Counter
1 channel
(32-bit) 1
DIO
8 channels
8
USB
Full-speed
USB 2.0
Compliant
Interface
SPI D/A 8
4
D/A 4
SYNCLD 1
4-channel
Quad Analog Voltage
Output
8 channels (16-bit)
Figure 2. USB-3103 block diagram
Software features
For information on the features of InstaCal and the other software included with your USB-3103, refer to the
www.mccdaq.com/PDFs/manuals/DAQ-Software-Quick-Start.pdf.
Check www.mccdaq.com/download.htm for the latest software version.

10
Chapter 2
Installing the USB-3103
What comes with your USB-3103 shipment?
The following items are shipped with the USB-3103.
Hardware
USB-3103 device
USB cable (2 meter length)
Additional documentation
In addition to this hardware user's guide, you should also receive the Quick Start Guide (available in PDF at
www.mccdaq.com/PDFs/manuals/DAQ-Software-Quick-Start.pdf). This booklet supplies a brief description
of the software you received with your USB-3103 and information regarding installation of that software.
Please read this booklet completely before installing any software or hardware.
Unpacking the USB-3103
As with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the USB-3103 from its packaging, ground yourself using a wrist strap or by simply
touching the computer chassis or other grounded object to eliminate any stored static charge.

USB-3103 User's Guide Installing the USB-3103
11
If any components are missing or damaged, notify Measurement Computing Corporation immediately by
phone, fax, or e-mail:
Phone: [phone] and follow the instructions for reaching Tech Support.
Fax: [phone] to the attention of Tech Support
Email: [email protected]
Installing the software
Refer to the Quick Start Guide for instructions on installing the software on the Measurement Computing Data
Acquisition Software CD. This booklet is available in PDF at www.mccdaq.com/PDFs/manuals/DAQ-
Software-Quick-Start.pdf.
Installing the hardware
Be sure you are using the latest system software
Before you connect the USB-3103, make sure that you are using the latest versions of the USB drivers.
Before installing the USB-3103, download and install the latest Microsoft Windows updates. In particular,
when using Windows XP, make sure you have XP Hotfix KB822603 installed. This update is intended to
address a serious error in Usbport.sys when you operate a USB device. You can run Windows Update or
download the update from www.microsoft.com/downloads/details.aspx?familyid=733dd867-56a0-4956-b7fe-
e85b688b7f86&displaylang=en. For more information, refer to the Microsoft Knowledge Base article
"Availability of the Windows XP SP1 USB 1.1and 2.0update." This article is available at
support.microsoft.com/?kbid=822603.
Connecting the USB-3103 to your system
To connect the USB-3103 to your system, turn your computer on, and connect the USB cable to a USB port on
your computer or to an external USB hub that is connected to your computer. The USB cable provides power
and communication to the USB-3103.
When you connect the USB-3103 for the first time, a Found New Hardware popup balloon (Windows XP) or
dialog (other Windows versions) appears as the USB-3103 is detected by your computer.
After the USB-3103 is installed, the popup balloon or dialog states "Your new hardware is installed and ready
to use," and the power LED should flash and then remain lit. This indicates that communication is established
between the USB-3103 and your computer.
Caution! Do not disconnect any device from the USB bus while the computer is communicating with the
USB-3103, or you may lose data and/or your ability to communicate with the USB-3103.

USB-3103 User's Guide Installing the USB-3103
12
If the power LED turns off
If the power LED is illuminated but then turns off, the computer has lost communication with the USB-3103.
To restore communication, disconnect the USB cable from the computer, and then reconnect it. This should
restore communication, and the power LED should turn back on.
Calibrating the USB-3103
The USB-3103 is shipped fully calibrated. Calibration coefficients are stored in the device FLASH memory.
Return the device to Measurement Computing Corporation when calibration is required. The normal calibration
interval is once per year.

13
Chapter 3
Functional Details
External components
The USB-3103 has the following external components, as shown in Figure 3.
USB connector
Status LED
Power LED
Screw terminal banks (2)
Screw terminal
pins 1 to 28
Screw terminal
pins 29 to 56
USB
connector
Power LED
Status LED
Figure 3. USB-3103 external components
USB connector
The USB connector provides power and communication to the USB-3103. The voltage supplied through the
USB connector is system-dependent, and may be less than 5 V. No external power supply is required.
Status LED
The Status LED indicates the communication status of the USB-3103. It flashes when data is being transferred,
and is off when the USB-3103 is not communicating. This LED uses up to 10 mA of current and cannot be
disabled.
Power LED
The power LED lights up when the USB-3103 is connected to a USB port on your computer or to an external
USB hub that is connected to your computer.

USB-3103 User's Guide Functional Details
14
Screw terminal banks
The USB-3103 has two rows of screw terminals—one row on the top edge of the housing, and one row on the
bottom edge. Each row has 28 connections. Use 16 AWG to 30 AWG wire gauge when making screw terminal
connections. Pin numbers are identified in Figure 4.
Pin 56Pin 29
Pin 28Pin 1
Figure 4. USB-3103 screw terminal pin numbering
Screw terminal –pins 1-28
The screw terminals on the bottom edge of the USB-3103 (pins 1 to 28) provide the following connections:
Four analog voltage output connections (VOUT0, VOUT2, VOUT4, VOUT6)
Four analog ground connections (AGND)
Eight digital I/O connections (DIO0 to DIO7)
Screw terminal –pins 29-56
The screw terminals on the top edge of the USB-3103 (pins 29 to 56) provide the following connections:
Four analog voltage output connections (VOUT1, VOUT3, VOUT5, VOUT7)
Four analog ground connections (AGND)
One SYNC terminal for external clocking and multi-unit synchronization (SYNCLD)
Three digital ground connections (DGND)
One external event counter connection (CTR)
One digital I/O pull-down resistor connection (DIO CTL)
One voltage output power connection (+5 V)

USB-3103 User's Guide Functional Details
15
29 VOUT1 30 NC 31 VOUT3 32 NC 33 AGND 34 VOUT5 35 NC 36 VOUT7 37 NC 38 AGND 39 NC 40 NC 41 NC 42 NC 43 AGND 44 NC 45 NC 46 NC 47 NC 50 DGND 51 NC 52 CTR 53 DGND 54 DIO CTL 55 DGND 56 +5V 48 AGND 49 SYNCLD
VOUT0 1 NC 2 VOUT2 3 NC 4 AGND 5 VOUT4 6 NC 7 VOUT6 8 NC 9 AGND 10 NC 11 NC 12 NC 13 NC 14 AGND 15 NC 16 NC 17 NC 18 NC 19 AGND 20 DIO0 21 DIO1 22 DIO2 23 DIO3 24 DIO4 25 DIO5 26 DIO6 27 DIO7 28
Figure 5. USB-3103 signal pin out
Analog voltage output terminals (VOUT0 to VOUT7)
The screw terminal pins labeled VOUT0 to VOUT7 are voltage output terminals (see Figure 5). The voltage
output range for each channel is software-programmable for either bipolar or unipolar. The bipolar range is
±10 V, and the unipolar range is 0 to 10 V. The channel outputs may be updated individually or simultaneously.
Digital I/O terminals (DIO0 to DIO7)
You can connect up to eight digital I/O lines to the screw terminals labeled DIO0 to DIO7 (pins 21 through 28).
You can configure each digital bit for either input or output.
When you configure the digital bits for input, you can use the digital I/O terminals to detect the state of any
TTL level input. Refer to the switch shown in Figure 6 and the schematic shown in Figure 7. When the switch
is set to the +5 V USER input, DIO7 reads TRUE (1). If you move the switch to DGND, DIO7 reads FALSE
(0).
Pin 53
DGND
Pin 56
+5V
Pin 28
DIO7
Figure 6. DIO7 detecting the state of a switch
+5V
DGND
DIO7
Figure 7. Schematic showing DIO7 detecting the state of
a switch

USB-3103 User's Guide Functional Details
16
For more information on digital signal connections
For more information on digital signal connections and digital I/O techniques, refer to the Guide to Signal
Connections (available on our web site at www.mccdaq.com/pdfs/DAQ-Signal-Connections.pdf).
Digital I/O control terminal (DIO CTL) for pull-up/down configuration
All digital pins are floating by default. When inputs are floating, the state of unwired inputs are undefined (they
may read high or low). You can configure the inputs to read a high or low value when they aren’t wired. Use
the DIO CTL connection (pin 54) to configure the digital pins for pull-up (inputs read high when unwired) or
pull-down (inputs read low when unwired).
To pull up the digital pins to +5V, wire the DIO CTL terminal pin to the +5V terminal pin (pin 56).
To pull down the digital pins to ground (0 volts), wire the DIO CTL terminal pin to a DGND terminal pin
(pin 50, 53, or 55).
Ground terminals (AGND, DGND)
Eight analog ground (AGND) connections provide a common ground for all analog voltage output channels.
Three digital ground (DGND) connections provide a common ground for the DIO, CTR, SYNCLD and +5V
connections.
Synchronous DAC load terminal (SYNCLD)
The synchronous DAC load connection (pin 49) is a bidirectional I/O signal that allows you to simultaneously
update the DAC outputs on multiple devices. You can use this pin for two purposes:
Configure as an input (slave mode) to receive the D/A LOAD signal from an external source.
When the SYNCLD pin receives the trigger signal, the analog outputs are updated simultaneously.
SYNCLD pin must be logic low in slave mode for immediate update of DAC outputs
When the SYNCLD pin is in slave mode, the analog outputs can be updated immediately or when a positive
edge is seen on the SYNCLD pin (this is under software control.)
The SYNCLD pin must be at a low logic level for DAC outputs to update immediately. If the external source
supplying the D/A LOAD signal is pulling the SYNCLD pin high, no update will occur.
Refer to the "USB-3100 Series" section in the Universal Library User's Guide for information on how to
update DAC outputs immediately.
Configure as an output (master mode) to send the internal D/A LOAD signal to the SYNCLD pin.
You can use the SYNCLD pin to synchronize with a second USB-3103 and simultaneously update the
DAC outputs on each device. Refer to Synchronizing multiple units on page 17.
Use InstaCal to configure the SYNCLD mode as master or slave. On power up and reset the SYNCLD pin is
set to slave mode (input).
Refer to the "USB-3100 Series" section in the Universal Library User's Guide for information on how to
configure the USB-3103 with the Universal Library.
Counter terminal (CTR)
The CTR connection (pin 52) is the input to the 32-bit event counter. The internal counter increments when the
TTL levels transition from low to high. The counter can count frequencies of up to 1 MHz.
Power terminal (+5V)
The +5 V connection (pin 56) draws power from the USB connector. This terminal is a +5V output.

USB-3103 User's Guide Functional Details
17
Caution! The +5V terminal is an output. Do not connect to an external power supply or you may damage
the USB-3103 and possibly the computer.
Synchronizing multiple units
You can connect the SYNCLD terminal pin (pin 49) of two USB-3103 units together in a master/slave
configuration and simultaneously update the DAC outputs of both devices. Do the following.
1. Connect the SYNCLD pin of the master USB-3103 to the SYNCLD pin of the slave USB-3103.
2. Configure the SYNCLD pin on the slave device for input to receive the D/A LOAD signal from the master
device. Use InstaCal to set the direction of the SYNCLD pin.
3. Configure the SYNCLD pin on the master device for output to generate an output pulse on the SYNCLD
pin.
Set the Universal Library SIMULTANEOUS option for each device. Refer to the Universal Library User's Guide
for information on how to configure the USB-3103 with the Universal Library.
When the SYNCLD pin on the slave device receives the signal, the analog output channels on each device are
updated simultaneously.
An example of a master/slave configuration is shown here.
S
Slave
PMD-1608F
Master
device Slave
device
SYNCLD pin
(terminal pin 49)
D/A LOAD signal
Configure the SYNCLD
pin for output Configure the SYNCLD pin for input
Figure 8. Synchronizing the update of multiple devices

18
Chapter 4
Specifications
Typical for 25 °C unless otherwise specified.
Specifications in italic text are guaranteed by design.
Analog voltage output
Table 1. Analog voltage output specifications
Parameter
Conditions
Specifications
Digital to Analog converter
DAC8554
Number of channels
8
Resolution
16 bits
Output ranges
Calibrated
±10 V, 0 to 10 V
Software configurable
Un-calibrated
±10.2 V, -0.04 to 10.08 V
Software configurable
Output transient
±10 V to (0 to 10 V) or
(0 to 10 V) to ±10 V range
selection.
(Note 1)
Duration: 5 µS typ.
Amplitude: 5 V p-p typ.
Host PC is reset, powered on,
suspended or a reset command is
issued to device.
(Note 2)
Duration: 2 S typ.
Amplitude: 2 V p-p typ.
Initial power on
Duration: 50 mS typ.
Amplitude: 5 V peak typ.
Differential non-linearity
(Note 3)
Calibrated
±1.25 LSB typ.
-2 LSB to +1 LSB max.
Un-calibrated
±0.25 LSB typ.
±1 LSB max.
Output current
VOUTx pins
±3.5 mA typ.
Output short-circuit protection
VOUTx connected to AGND
Indefinite
Output coupling
DC
Power on and reset state
DACs cleared to zero-scale: 0 V, ±50 mV typ.
Output range: 0-10 V
Output noise
0 to 10 V range
14.95 µVrms typ.
±10 V range
31.67 µVrms typ.
Settling time
to 1 LSB accuracy
25 µS typ.
Slew rate
0 to 10 V range
1.20 V/µS typ.
±10 V range
1.20 V/µS typ.
Throughput
Single-channel
100 Hz max., system dependent
Multi-channel
100 Hz/#ch max., system dependent
Note 1: The USB-3103 output voltage level defaults to 0 V whenever the output voltage range is
reconfigured.
The USB-3103 output voltage level will also default to 0 V:
1) Whenever the host PC is reset, shut down or suspended.
2) If a reset command is issued to the device.

USB-3103 User's Guide Specifications
19
Note 2: The duration of this particular output transient is highly dependent on the enumeration process of
the host PC. Typically the output of the USB-3103 is stable after 2 seconds.
Note 3: The maximum differential non-linearity specification applies to the entire 0 to 70 °C temperature
range of the USB-3103. This specification also accounts for the maximum errors due to the
software calibration algorithm (in Calibrated mode only) and the DAC8554 digital to analog
converter non-linearities.
Table 2. Absolute accuracy specifications –calibrated output
Range
Accuracy (±LSB)
±10 V
14.0
0 to 10 V
22.0
Table 3. Absolute accuracy components specifications –calibrated output
Range
% of reading
Offset (±mV)
Temp drift (%/°C)
Absolute accuracy at FS (±mV)
±10 V
±0.0183
1.831
0.00055
3.661
0 to 10 V
±0.0183
0.915
0.00055
2.746
Table 4. Relative accuracy specifications
Range
Relative accuracy (±LSB)
±10 V , 0 to 10 V
4.0 typ.
12.0 max.
Analog output calibration
Table 5. Analog output calibration specifications
Parameter
Conditions
Specifications
Recommended warm-up time
15 minutes min.
On-board precision reference
DC level: 5.000 V ±1 mV max.
Tempco: ±10 ppm/°C max.
Long term stability: ±10 ppm/SQRT(1000 hrs)
Calibration method
Software calibration
Calibration interval
1 year
Digital input/output
Table 6. Digital I/O specifications
Digital logic type
CMOS
Number of I/O
8
Configuration
Independently configured for input or output
Pull-up/pull-down configuration
(Note 4)
User configurable
All pins floating (default)
Digital I/O input loading
TTL (default)
47K ohms (pull-up/pull down configurations)
Digital I/O transfer rate (system paced)
System dependent, 33 to 1000 port reads/writes or single bit reads/writes per
second.
Input high voltage
2.0 V min, 5.5 V absolute max
Input low voltage
0.8 V max, –0.5 V absolute min
Output high voltage (IOH = –2.5 mA)
3.8 V min
Output low voltage (IOL = 2.5 mA)
0.7 V max
Power on and reset state
Input

USB-3103 User's Guide Specifications
20
Note 4: Pull up and pull down configuration area available using the DIO CTL terminal block pin 54.
The pull down configuration requires the DIO CTL pin (pin 54) to be connected to a DGND pin
(pin 50, 53 or 55). For a pull up configuration, the DIO CTL pin should be connected to the +5 V
terminal pin (pin 56).
Synchronous DAC Load
Table 7. SYNCLD I/O specifications
Parameter
Conditions
Specification
Pin name
SYNCLD (terminal block pin 49)
Power on and reset state
Input
Pin type
Bidirectional
Termination
Internal 100K ohms pull-down
Software selectable direction
Output
Outputs internal D/A LOAD signal.
Input
Receives D/A LOAD signal from external source.
Input clock rate
100 Hz max
Clock pulse width
Input
1 µs min
Output
5 µs min
Input leakage current
±1.0 µA typ.
Input high voltage
4.0 V min, 5.5 V absolute max
Input low voltage
1.0 V max, –0.5 V absolute min
Output high voltage (Note 5)
IOH = –2.5 mA
3.3 V min
No load
3.8 V min
Output low voltage (Note 6)
IOL = 2.5 mA
1.1 V max
No load
0.6 V max
Note 5: SYNCLD is a Schmitt trigger input and is over-current protected with a 200 Ohm series resistor.
Note 6: When SYNCLD is in input mode, the analog outputs may either be updated immediately or when
a positive edge is seen on the SYNCLD pin (this is under software control.) However, the pin
must be at a low logic level in order for the DAC outputs to be updated immediately. If an
external source is pulling the pin high, no update will occur.
Counter
Table 8. CTR I/O specifications
Parameter
Conditions
Specification
Pin name
CTR
Number of channels
1
Resolution
32-bits
Counter type
Event counter
Input type
TTL, rising edge triggered
Counter read/writes rates
(software paced)
Counter read
System dependent, 33 to 1000 reads per second.
Counter write
System dependent, 33 to 1000 reads per second.
Schmidt trigger hysteresis
20 mV to 100 mV
Input leakage current
±1.0 µA typ.
Input frequency
1 MHz max.
High pulse width
500 nS min.
Low pulse width
500 ns min.
Input high voltage
4.0 V min, 5.5 V absolute max
Input low voltage
1.0 V max, –0.5 V absolute min