SIGNALCORE SC5312A Owner's manual

SC5312A
400 MHz to 6 GHz IQ Demodulator
PXI Express Interface
Operating and Programming Manual
© 2013-2020 SignalCore, Inc.
[e-mail]

SC5312A Operating & Programming Manual i
CO N T E N T S
Important Information 1
Warranty 1
Copyright & Trademarks 1
International Materials Declarations 2
CE European Union EMC & Safety Compliance Declaration 2
Warnings Regarding Use of SignalCore Products 3
Getting Started 4
Unpacking 4
Verifying the Contents of your Shipment 4
Setting Up and Configuring the SC5312A 4
RF Signal Connections 6
Baseband Connections 7
Indicator LED 7
SC5312A Theory of Operation 8
Overview 8
RF Input Section 8
LO Input Section 10
IF Output Section 11
SC5312A Programming Interface 12
Device Drivers 12
Using the Application Programming Interface (API) 12
Setting the SC5312A: Writing to Configuration Registers 13
Configuration Registers 13
Initializing the Device 14
Setting the System Active LED 14
Setting the RF Frequency 14
Setting RF Input RF Amplifiers 14
Setting the RF Attenuation 14
Setting the RF Path 14

SC5312A Operating & Programming Manual ii
Selecting the RF Filter 14
Selecting the LO Filter 14
Enabling LO Output 15
Setting the IF Gain 15
Setting the Common Output Voltage 15
Removing DC Offset in Differential Amplifiers 15
Setting the Output Linearity of the IQ Demodulator 15
Storing the Startup State 15
Writing to the User EEPROM 16
Querying the SC5312A: Writing to Request Registers 17
Reading the Device Temperature 17
Reading the Device Status 17
Reading the User EEPROM 18
Reading the Calibration EEPROM 18
Calibration EEPROM Map 19
Software API Library Functions 20
Constants Definitions 21
Type Definitions 22
Function Definitions and Usage 22
Calibration & Maintenance 29

SC5312A Operating & Programming Manual Rev 1.0.2 1
IM P O R T A N T IN F O R M A T I O N
Warranty
This product is warranted against defects in materials and workmanship for a period of three years from
the date of shipment. SignalCore will, at itsoption, repair or replace equipment that proves to be defective
during the warranty period. This warranty includes parts and labor.
Before any equipment will be accepted for warranty repair or replacement, a Return Material
Authorization (RMA) number must be obtained from a SignalCore customer service representative and
clearly marked on the outside of the return package. SignalCore will pay all shipping costs relating to
warranty repair or replacement.
SignalCore strives to make the information in this document as accurate as possible. The document has
been carefully reviewed for technical and typographic accuracy. In the event that technical or
typographical errors exist, SignalCore reserves the right to make changes to subsequent editions of this
document without prior notice to possessors of this edition. Please contact SignalCore if errors are
suspected. In no event shall SignalCore be liable for any damages arising out of or related to this document
or the information contained in it.
EXCEPT AS SPECIFIED HEREIN, SIGNALCORE, INCORPORATED MAKES NO WARRANTIES, EXPRESS OR
IMPLIED, AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. CUSTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE
ON THE PART OF SIGNALCORE, INCORPORATED SHALL BE LIMITED TO THE AMOUNT THERETOFORE
PAID BY THE CUSTOMER. SIGNALCORE, INCORPORATED WILL NOT BE LIABLE FOR DAMAGES RESULTING
FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR CONSEQUENTIAL DAMAGES,
EVEN IF ADVISED OF THE POSSIBILITY THEREOF. This limitation of the liability of SignalCore, Incorporated
will apply regardless of the form of action, whether in contract or tort, including negligence. Any action
against SignalCore, Incorporated must be brought within one year after the cause of action accrues.
SignalCore, Incorporated shall not be liable for any delay in performance due to causes beyond its
reasonable control. The warranty provided herein does not cover damages, defects, malfunctions, or
service failures caused by owner’s failure to follow SignalCore, Incorporated’s installation, operation, or
maintenance instructions; owner’s modification of the product; owner’s abuse, misuse, or negligent acts;
and power failure or surges, fire, flood, accident, actions of third parties, or other events outside
reasonable control.
Copyright & Trademarks
Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic
or mechanical, including photocopying, recording, storing in an information retrieval system, or
translating, in whole or in part, without the prior written consent of SignalCore, Incorporated.
SignalCore, Incorporated respects the intellectual property rights of others, and we ask those who use our
products to do the same. Our products are protected by copyright and other intellectual property laws.
Use of SignalCore products is restricted to applications that do not infringe on the intellectual property
rights of others.

SC5312A Operating & Programming Manual Rev 1.0.2 2
“SignalCore”, “signalcore.com”, and the phrase “preserving signal integrity” are registered trademarks of
SignalCore, Incorporated. Other product and company names mentioned herein are trademarks or trade
names of their respective companies.
International Materials Declarations
SignalCore, Incorporated uses a fully RoHS compliant manufacturing process for our products. Therefore,
SignalCore hereby declares that its products do not contain restricted materials as defined by European
Union directive 2002/95/EC (EU RoHS) in any amounts higher than limits stated in the directive. This
statement is based on the assumption of reliable information and data provided by our component
suppliers and may not have been independently verified through other means. For products sold into
China, we also comply with the “Administrative Measure on the Control of Pollution Caused by Electronic
Information Products” (China RoHS). In the current stage of this legislation, the content of six hazardous
materials must be explicitly declared. Each of those materials, and the categorical amount present in our
products, are shown below:
組成名稱
Model Name
鉛
Lead
(Pb)
汞
Mercury
(Hg)
镉
Cadmium
(Cd)
六价铬
Hexavalent
Chromium
(Cr(VI))
多溴联苯
Polybrominated
biphenyls
(PBB)
多溴二苯醚
Polybrominated
diphenyl ethers
(PBDE)
SC5312A
✓
✓
✓
✓
✓
✓
A ✓indicates that the hazardous substance contained in all of the homogeneous materials for this
product is below the limit requirement in SJ/T11363-2006. An Xindicates that the particular hazardous
substance contained in at least one of the homogeneous materials used for this product is above the limit
requirement in SJ/T11363-2006.
CE European Union EMC & Safety Compliance Declaration
The European Conformity (CE) marking is affixed to products with input of 50 - 1,000 Vac or 75 - 1,500
Vdc and/or for products which may cause or be affected by electromagnetic disturbance. The CE marking
symbolizes conformity of the product with the applicable requirements. CE compliance is a
manufacturer’s self-declaration allowing products to circulate freely within the European Union (EU).
SignalCore products meet the essential requirements of Directives 2004/108/EC (EMC) and 2006/95/EC
(product safety) and comply with the relevant standards. Standards for Measurement, Control and
Laboratory Equipment include EN 61326 and EN 55011 for EMC, and EN 61010-1 for product safety.

SC5312A Operating & Programming Manual Rev 1.0.2 3
Warnings Regarding Use of SignalCore Products
(1)
PRODUCTS FOR SALE BY SIGNALCORE, INCORPORATED ARE NOT DESIGNED WITH COMPONENTS NOR TESTED FOR A LEVEL OF
RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT
SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN.
(2)
IN ANY APPLICATION, INCLUDING THE ABOVE, RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY
ADVERSE FACTORS, INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY, COMPUTER HARDWARE
MALFUNCTIONS, COMPUTER OPERATING SYSTEM SOFTWARE FITNESS, FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED
TO DEVELOP AN APPLICATION, INSTALLATION ERRORS, SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS, MALFUNCTIONS OR
FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES, TRANSIENT FAILURES OF ELECTRONIC SYSTEMS (HARDWARE AND/OR
SOFTWARE), UNANTICIPATED USES OR MISUSES, OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER (ADVERSE
FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED “SYSTEM FAILURES”). ANY APPLICATION WHERE A SYSTEM FAILURE
WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS (INCLUDING THE RISK OF BODILY INJURY AND DEATH) SHOULD NOT BE
SOLELY RELIANT UPON ANY ONE COMPONENT DUE TO THE RISK OF SYSTEM FAILURE. TO AVOID DAMAGE, INJURY, OR DEATH, THE
USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES, INCLUDING BUT
NOT LIMITED TO BACK-UP OR SHUT DOWN MECHANISMS. BECAUSE EACH END-USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM
SIGNALCORE' TESTING PLATFORMS, AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE SIGNALCORE PRODUCTS IN
COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY SIGNALCORE, THE USER OR
APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF SIGNALCORE PRODUCTS
WHENEVER SIGNALCORE PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION, INCLUDING, WITHOUT LIMITATION, THE
APPROPRIATE DESIGN, PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.

SC5312A Operating & Programming Manual Rev 1.0.2 4
GE T T I N G ST A R T E D
Unpacking
All SignalCore products ship in antistatic packaging (bags) to prevent damage from electrostatic discharge
(ESD). Under certain conditions, an ESD event can instantly and permanently damage several of the
components found in SignalCore products. Therefore, to avoid damage when handling any SignalCore
hardware, you must take the following precautions:
Remove the product from its packaging and inspect it for loose components or any signs of damage. Notify
SignalCore immediately if the product appears damaged in any way.
Verifying the Contents of your Shipment
Verify that your SC5312A kit contains the following items:
Quantity
Item
1
SC5312A IQ Demodulator
1
USB Flash Drive Installation Software (may be combined with other products onto a single drive)
1
Getting Started Guide
Setting Up and Configuring the SC5312A
The SC5312A is a designed for use in a PXIe or PXIe hybrid chassis. Chassis manufacturers must provide at
least the minimum required per-slot power dissipation cooling capability to be compliant with the PXIe
specifications. The SC5312A is designed to be sufficiently cooled in either all-PXIe chassis or PXIe hybrid
chassis (PXI Express chassis with traditional PXI slots). However, certain environmental factors may
degrade performance. Inadequate cooling can cause the temperature inside the RF housing to rise above
the maximum for this product, leading to improper performance and potentially reducing product lifespan
or causing complete product failure. Maintain adequate air space around the chassis at all times, and keep
the chassis fan filters clean and unobstructed.
Refer to your chassis manufacturer’s user manual for proper setup and maintenance of your
PXIe or PXIe hybrid chassis. The SC5312A on-board temperature sensor should indicate a rise
of no more than 20 °C above ambient temperature under normal operating conditions.
!
•Ground yourself using a grounding strap or by touching a grounded metal object.
•Touch the antistatic bag to a grounded metal object before removing the hardware
from its packaging.
•Never touch exposed signal pins. Due to the inherent performance degradation caused
by ESD protection circuits in the RF path, the device has minimal ESD protection
against direct injection of ESD into the RF signal pins.
•When not in use, store all SignalCore products in their original antistatic bags.
!

SC5312A Operating & Programming Manual Rev 1.0.2 5
The SC5312A is a PXIe-based IQ demodulator with all I/O connections and indicators located on the front
face of the module as shown below. Each location is discussed in further detail below.
Figure 1. Front panel view of the SC5312A.

SC5312A Operating & Programming Manual Rev 1.0.2 6
All RF signal connections (ports) on the SC5312A are SMA-type. Exercise caution when fastening cables to
the signal connections. Over-tightening any connection can cause permanent damage to the device.
The condition of your system‘s signal connections can significantly affect measurement
accuracy and repeatability. Improperly mated connections or dirty, damaged or worn
connectors can degrade measurement performance. Clean out any loose, dry debris from
connectors with clean, low-pressure air (available in spray cans from office supply stores).
If deeper cleaning is necessary, use lint-free swabs and isopropyl alcohol to gently clean inside
the connector barrel and the external threads. Do not mate connectors until the alcohol has
completely evaporated. Excess liquid alcohol trapped inside the connector may take several
days to fully evaporate and may degrade measurement performance until fully evaporated.
Tighten all SMA connections to 5 in-lb max (56 N-cm max)
RF Signal Connections
LO OUT
This port outputs the tunable LO signal allowing phase-coherent daisy-
chaining of multiple IQ demodulator modules. The connector is SMA female.
The nominal output impedance is 50 Ω.
RF IN
This port accepts an RF signal ranging from 400 MHz to 6 GHz. The connector
is SMA female. The nominal input impedance is 50 Ω. Maximum input power
is +23 dBm with ATTEN #1 set to at least 10 dB attenuation.
RF AUX IN
This port accepts an RF signal ranging from 400 MHz to 6 GHz. This port can
be used as an alternate path for system-level calibration. The connector is
SMA female. The nominal input impedance is 50 Ω.
LO IN
This port accepts a tunable LO signal from an external source to drive the
demodulator. The connector is SMA female. This port is AC-coupled with a
nominal input impedance of 50 Ω. Maximum input power is +10 dBm.
!
!

SC5312A Operating & Programming Manual Rev 1.0.2 7
Baseband Connections
The SC5312A has four baseband output ports, comprised of differential in-phase (I+ and I-) and differential
quadrature (Q+ and Q-) outputs. Nominal differential output impedance is 100 Ω. The demodulator can
also be configured for single-ended or differential IF output. When configured for single-ended operation,
it is recommended to terminate the other half of the differential pair using a 50 Ω terminator. All
baseband connectors are MCX female.
Indicator LED
The SC5312A provides visual indication of important modes. There is one LED indicator on the unit. Its
behavior under different operating conditions is shown in Table 1.
Table 1. LED indicator states.
LED
Color
Definition
STATUS
Green
“Power good” and device is ready.
STATUS
Off
Power fault. Contact SignalCore.
ACTIVE
Green/Off
Device is open (green) /closed (off). This indicator is also
user programmable (see register map).

SC5312A Operating & Programming Manual Rev 1.0.2 8
SC5 3 1 2 A TH E O R Y O F OP E R A T I O N
Overview
The SC5312A is a single-stage, direct conversion Inphase-Quadrature (IQ) demodulating mixer. The
SC5312A can operate as a single-stage downconverter or as an IQ demodulator. The SC5312A
demodulator operates in the 400 MHz to 6 GHz RF range with a typical 3 dB IF bandwidth of 160 MHz in
single-stage converter mode, or 320 MHz in IQ mode. The RF input stage has adjustable gain to allow the
user to adjust the incoming RF signal prior to the demodulation process for the purpose of optimizing RF
dynamic range. The IF stage has adjustable gain to ensure that linearity and noise of the IF output are
optimized. The SC5312A has the necessary RF amplifiers, attenuators, IF amplifiers, and IF control via DACs
to allow the user to optimally operate the device over the entire frequency range as well as for both small
and large RF input levels. Figure 2 shows a simplified block diagram of the SC5312A, showing only the
signal conditioning components critical for the following discussion. The following sections provide an in-
depth discussion on how to optimize the converter for linearity and signal-to-noise dynamic range.
RF Input Section
In the design of the RF input section, care was taken to ensure that the dynamic range of the IQ
demodulator is preserved as seen at the input port of the device. This requires that the demodulator is
not driven too hard (high signal amplitude) or too soft (low signal amplitude). When the device is driven
hard, nonlinear effects dominate the system. When driven too softly, signal-to-noise dynamic range
suffers. A general rule is to apply more attenuation earlier in the RF signal path to improve linearity, and
more gain to improve signal-to-noise performance. As an example, for a given input signal level and while
maintaining a relatively constant output IF level, the user would switch in RF AMP#1 and apply attenuation
on ATTEN#3 to improve signal-to-noise dynamic range. The factory default state sets all the RF amplifiers
off, all attenuators to 0 dB attenuation, and the IF gain to 8 dB (DAC code of 32). In this default state, the
device is optimized for a -10 dBm RF signal in the 1.0 GHz to 2.4 GHz range. The IF output is typically 0.5
V - 1.0 V peak-to-peak differential at these settings.
The RF amplifiers are used to improve the gain of the device if the input signal is too low or when the
losses at higher frequencies are large. RF AMP#1 is usually selected when the RF signals are lower than -
25 dBm at the input port. With RF AMP#1 enabled, the device sensitivity is improved and the detection of
low level signals is better resolved. RF AMP#2 should be selected and switched into the signal path at RF
frequencies greater than 5 GHz, where the signal power loss through the front end prior to the
demodulator can be as high as 15 dB due to filter and switch insertion losses. At these high RF frequencies,
if the IF gain is at its maximum of 15.75 dB (DAC code = 63) and the IF output level falls below -10 dBm (or
outside the digitizers optimal levels), RF AMP#2 should be enabled.

SC5312A Operating & Programming Manual Rev 1.0.2 9
Vocm
Dac
DC
Offset
DAC
2.5V
Ref
i+
i-
5V
Ref
Vocm
Variable
Diff Amp
Vocm Vocm
Out Diff
Amp
IQ
Demodulator
Linearity
Dac
90
0
i+
i-
50W 50W
RF Amp
#1 RF Amp
#3 RF Amp
#2
9 Selectable
RF Filters
9 Selectable
LO Filters
LO Amp
#2
LO Amp
#1
Gain
Selectable
IF Diff_Amp
RF Atten
#1 RF Atten
#2 RF Atten
#3
Figure 2. Simplified block diagram of the SC5312A.

SC5312A Operating & Programming Manual Rev 1.0.2 10
The RF attenuators provide attenuation when required. RF ATTEN#1 attenuation should be stepped up as
the signal power at the RF port increases above -10 dBm. Nonlinear components of the signal such as
IMD3 and second order harmonics will increase in magnitude as the input signal increases; therefore the
user should exercise good judgment to determine when to use RF ATTEN#1. Do not over attenuate
because this will hurt the signal to noise ratio.
RF ATTEN#2 is used if the input signal needs further suppression to improve linearity. It should also be
used if RF AMP#1 is enabled to improve sensitivity, but, as a result, the level at the input of RF AMP#3
(always in the path) may be too high. Step up the attenuation of RF ATTEN#2 to ensure the system
(resulting from RF AMP#3) is not driven too hard. RF ATTEN#3 is used to control the level to the IQ
demodulator when RF AMP#2 is enabled (switched into the signal path).
There is also an auxiliary RF input to the device. This input is almost identical to the main RF input with
the exception of having an extra switch path. The intended use of this port is to allow the user a calibration
path without having to detach the device under test (DUT) already cabled to the main RF input port. The
user must perform in-situ equalization to remove IQ errors such as phase imbalance and quadrature gain
offsets that are inherent to the device. Providing this auxiliary path makes the task of characterizing the
system with and without a DUT present much easier.
There are nine low pass filters in the RF filter bank. These filters are automatically selected when the user
enters the operating frequency. These filters can also be selected manually. As with all filters there is
generally an amplitude roll-off as the frequency nears its 3 dB cutoff point so it is important to understand
that frequencies near to the cutoff point may experience a slightly faster roll-off of their IF bandwidth. A
typical 1 dB IF bandwidth (IQ) is about 160 MHz. The user may want to choose a higher frequency filter if
this becomes a problem. See the programming section in this manual for more details. The filters in both
the RF and LO filter banks are identical and are listed below.
Filter Number
1 dB Cutoff Frequency
0
400 MHz
1
500 MHz
2
650 MHz
3
1000 MHz
4
1400 MHz
5
2000 MHz
6
2825 MHz
7
3800 MHz
8
6000 MHz
LO Input Section
The SC5312A requires an external RF signal as its “Local Oscillator” (LO) for the frequency conversion
process. The external RF signal must be connected to the “LO in”port. The typical required input level is -
3 dBm to 3 dBm. These levels are required to sufficiently drive the IQ demodulator for good linearity
performance and conversion loss. The LO signal is conditioned through a bank of low-pass filters to reduce

SC5312A Operating & Programming Manual Rev 1.0.2 11
the signal harmonics. Reducing the harmonics produces a “purer” signal tone, improving the duty cycle of
the LO as it drives the mixers of the demodulator. Additionally, the LO signal can be passed out of the
device via the “LO out” port. This output can be used as the input LO source for another demodulator, for
example. Driving multiple demodulators with the same derived LO signal optimizes phase coherency
between them. When this port is not in use, it is highly recommended to terminate it into a 50 Wload.
IF Output Section
The IF outputs are differentially driven. Each of the in-phase and quadrature components of the
demodulator is conditioned prior to leaving the IF ports. The user can programmatically adjust the
parameters of the differential signal such as the common output voltage, DC offset between the (-) and
(+) terminals, and its amplitude. The differential output impedance of each component is 100 W. However,
all ports can be operated as single-ended 50 Wports. All unused ports should be terminated into 50 W
loads.
There are voltage DACs within the device to control the signal parameters of each of the IQ components.
For each component, the Vcom (common voltage) DAC controls the common output voltage of the
differential outputs. The Vcom DAC values range from 0 to 16383 (14 bits) and change the voltage
between 1 V to 3.5 V. For a wider output voltage swing range, this voltage should be set to around 2.4 V
to 2.5 V. Having a wider swing range improves the output compression point of the device. This is not a
hard requirement and the user will need to adjust the voltage levels to suit their specific requirements.
As an example, setting to some other voltage may be required to optimize the dynamic range of the
receiving digitizer and therefore, better optimize the entire system.
DC offsets may limit the dynamic range of the receiving digitizer, and where it is critical the user can “tune
out” to minimize these offsets using the DC Offset DAC. This 14 bit DAC can correct offsets up to +/-0.050
V with about 0.020 mV resolution.
The IF amplifiers have an adjustable gain range of 15.75 dB with a tuning resolution of 0.25 dB. The gain
is controlled by programming a 6-bit DAC whose codes range from 0 to 63. Writing 63 to the DAC provides
the highest gain. Increasing the IF gain instead of the RF gain to achieve a required IF level will improve
the linearity of the system, but with the chance of a slight increase in output noise. For a common output
voltage of 2.4 V, the output compression/saturation point of the amplifier is around 10 dBm. It is
recommended to operate the output at least 6 dBm below this value to avoid running into saturation from
signals with high crest factors. When deciding the operating point of the digitizer, it is recommended that
the user not operate the output voltage too close to the saturation point of the digitizer input.
The linearity DAC controls the current flow through the demodulator core and thus affects the linearity
of the device. Generally, increasing the voltage results in higher the current consumption, and as a result
the linearity improves. However slight adjustments to the voltage may improve the linearity further; this
is dependent on the frequency and input power.

SC5312A Operating & Programming Manual Rev 1.0.2 12
SC5 3 1 2 A PR O G R A M M I N G IN T E R F A C E
Device Drivers
The SC5312A is programmed by writing to its set of configuration registers, and its data is read back
through its set of query registers. The user may program directly at register level or through the API library
functions provided. These API library functions are wrapper functions of the registers that simplify the
task of configuring the register bytes. The register specifics are covered in the next section. Writing to and
reading from the device at the register level through the API involves calls to the sc5312a_RegWrite and
sc5312a_RegRead functions respectively.
For Microsoft WindowsTM operating systems, The SC5312A API is provided as a dynamic linked library,
sc5312a.dll, which is available for 32-bit and 64-bit operating systems. This API is based on the libusb-1.0
library and therefore it is required to be installed on the system prior to development. The libusb-1.0.dll
will install along with the SC5312A.dll as well as the header files needed for development. Files required
for development are in the \win\Driver directory. SignalCore makes every effort to bundle the latest third-
party tools in our software installer. Occasionally however, third-party updates may not be identified and
bundled in time for a given product shipment. Therefore, for the latest version of libusb-1.0, please visit
http://libusbx.org. To install the necessary drivers, right click on the sc5312a.inf file under the \win
directory and select “Install.” After installation is completed, when the device is plugged into a USB port
and powered on, the host computer should identify the device and load the appropriate driver. For more
information, please see the SC5312A_Readme.txt file also located under the \Win directory.
A LabVIEW API is provided and it consists of function wrappers that call the sc5312a.dll. A LabVIEW API
written in G that uses NI-VISA is also available from the SignalCore website. The National Instruments
driver wizard that is part of NI-VISA can be used to create a driver for most operating systems. For the
SC5312A, the Vendor ID is 0x277C and the PID is 0x0018.
For Linux systems, the shared library libsc5312a.so is provided. To install the shared files and links, type
“make install” in the /Linux/ directory. The user may need to acquire root privileges to perform the install
operation. Ensure the libsub-1.0.X.dev package for the Linux distribution is installed on the host computer.
For other operating systems, users will need to write and compile their own drivers. The device register
map provides the necessary information to successfully implement a driver for the SC5312A. Driver code
based on libusb-1.0 is available to our customers by request. Should the user require assistance in writing
an appropriate API other than that provided, please contact SignalCore for additional example code and
hardware details.
Using the Application Programming Interface (API)
The SC5312A API library functions make it easy for the user to communicate with the device. Using the
API removes the need to understand register-level details - their configuration, address, data format, etc.
Commands to control the device are greatly simplified when using the API. For example, to obtain the
device temperature, the user simply calls the function sc5312a_GetDeviceTemperature, or calls
sc5312a_SetFrequency to tune the frequency. The software API is covered in detail in the “Software API
Library Functions” section.

SC5312A Operating & Programming Manual Rev 1.0.2 13
SE T T I N G T H E SC5 3 1 2 A : WR I T I N G T O
CO N F I G U R A T I O N RE G I S T E R S
Configuration Registers
The users may write the configuration registers (write only) directly by calling the sc5312a_RegWrite
function. The syntax for this function is sc5312a_RegWrite(deviceHandle, registerCommand,
instructWord). The instructWord takes a 64 bit-word. However, it will only send the required number of
bytes to the device. Table 2 summarizes the register addresses (commands) and the effective bytes of
command data.
Table 2. Configuration registers.
Register Name
Reg
Add
Serial
Range
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
INITIALIZE
0x01
[7:0]
Mode
SET_SYSTEM_ACTIVE
0x02
[7:0]
Enable
SYS LED
RF_FREQUENCY
0x10
[7:0]
MHz Frequency Word [7:0]
[15:8]
MHz Frequency Word [15:8]
[23:16]
MHz Frequency Word [23:16]
[31:24]
MHz Frequency Word [31:24]
[39:32]
MHz Frequency Word [39:32]
RF_AMPLIFIER
0x12
[7:0]
Amplifier
Mode
RF_ATTENUATION
0x13
[7:0]
Attenuation
[15:8]
Atten #
RF_PATH
0x14
[7:0]
Path
RF_FILTER_SELECT
0x15
[7:0]
Filter [3:0]
LO_FILTER_SELECT
0x16
[7:0]
Filter [3:0]
LO_OUT_ENABLE
0x17
[7:0]
Enable
LO Out
IF_GAIN_DAC
0x18
[7:0]
DAC value [5:0]
[15:8]
Channel
VCOM_OUT_DAC
0x19
[7:0]
DAC value [7:0]
[15:8]
DAC value [13:8]
[23:16]
Channel
DC_OFFSET_DAC
0x1A
[7:0]
DAC value [7:0]
[15:8]
DAC value [13:8]
[23:16]
Channel
LINEARITY_DAC
0x1B
[7:0]
DAC value [7:0]
[15:8]
DAC value [13:8]
STORE_STARTUP_STATE
0x1D
[7:0]
USER_EEPROM_WRITE
0x1F
[7:0]
Address [7:0]
[15:8]
Address [15:8]
[23:16]
Byte[7:0]

SC5312A Operating & Programming Manual Rev 1.0.2 14
Initializing the Device
INITIALIZE (0x01) - Writing 0x00 to this register will reset the device to the default power-on state. Writing
0x01 will reset the device but leave it in the current state. The user has the ability to define the default
startup state by writing to the STORE_STARTUP_STATE (0x1D) register, described later in this section.
Setting the System Active LED
SET_SYSTEM_ACTIVE (0x02) - This register simply turns on the front panel “active” LED with a write of
0x01 or turns off the LED with a write of 0x00. This register is generally written when the device driver
opens or closes the device.
Setting the RF Frequency
RF_FREQUENCY (0x10) - This register provides the device frequency information to set up the filters
appropriately. Data is sent as a 40 bit word with the LSB in Hz.
Setting RF Input RF Amplifiers
RF_AMPLIFIER (0x12) - This register enables or disables the RF amplifiers. Setting bit 0 low (0) disables
the RF amplifier. Setting bit 0 high (1) enables the RF amplifier. Bit 1 selects the amplifier; 0 for RF AMP#1,
1 for RF AMP#2.
Setting the RF Attenuation
RF_ATTENUATION (0x13) –Each of the attenuators is a 5 bit digital step attenuator with 1 dB per LSB.
Data is sent in 2 bytes; byte1 and bits [1:0] specifies the attenuator to program, and byte0 and bit [4:0]
specifies the attenuation value.
Setting the RF Path
RF_PATH (0x14) –Setting bit 0 low selects the main RF input path, while high will select the RF auxiliary
path.
Selecting the RF Filter
RF_FILTER_SELECT (0x15) –There are 9 RF filters to select from to improve RF input second harmonic
suppression. Bits [3:0] are used.
Selecting the LO Filter
LO_FILTER_SELECT (0x16) –There are 9 RF filters to select from to improve LO input second harmonic
suppression. Bits [3:0] are used.

SC5312A Operating & Programming Manual Rev 1.0.2 15
Enabling LO Output
LO_OUT_ENABLE (0x17) –Setting bit 0 high enables the LO signal to be ported out the LO output
connector. Note there is always a leakage out of this port and the levels could be as high as -30 dBm. It is
recommended to terminate this port into a 50 Wload if it is not used.
Setting the IF Gain
IF_GAIN_DAC (0x18) –Each of the channels has an adjustable IF amplifier with a step resolution of 0.25
dB per LSB. Writing the associated 6-bit DAC provides a gain range of 0 dB to 15.75 dB. Byte 1 selects the
channel, while byte 0 determines the DAC value. A maximum DAC value of 63 will provide maximum gain.
Setting the Common Output Voltage
VCOM_OUT_DAC (0x19) –The common output voltage of each channel of differential amplifiers can be
adjusted by writing to this DAC. The output voltage is linear in the region of 1.0 V to 3.5 V and follows the
equation:
  󰇡 
󰇢
Removing DC Offset in Differential Amplifiers
DC_OFFSET_DAC (0x1A) –The DC offset between the (+) and (-) terminals of the differential amplifier
output can be minimized by writing this DAC. Varying the DAC value from 0 to 16383 can correct up to
approximately  of DC offset error. This correction resolution is approximately 0.025 mV per LSB.
An approximation of the DAC value-to-offset voltage is given below.
   

Setting the Output Linearity of the IQ Demodulator
LINEARITY_DAC (0x19) –This DAC controls the current draw of the IQ modulator. As rule of thumb, the
more current, the better the linearity. However, the user may find that the linearity can be improved with
slight adjustments to the current consumption. The linearity is additionally dependent on the operating
frequency and input RF power levels. Typically, the DAC is set around 4.5 V using the following equation:
  󰇡 
󰇢
Storing the Startup State
STORE_STARTUP_STATE (0x23) –Writing to this register will save the current device state as the new
default power on (startup) state. All data written to this register will be ignored as only the write command
is needed to initiate the save.

SC5312A Operating & Programming Manual Rev 1.0.2 16
Writing to the User EEPROM
USER_EEPROM_WRITE (0x1B) - There is an onboard 32 kilobyte EEPROM for the user to store data. User
data is sent one byte at a time and is contained in the last (least significant) byte of the three bytes of data
written to the register. The other two bytes contain the write address in the EEPROM. For example, to
write user data 0x22 into address 0x1F00 requires writing 0x1F0022 to this register.

SC5312A Operating & Programming Manual Rev 1.0.2 17
QU E R Y I N G T H E SC5 3 1 2 A : WR I T I N G T O
RE Q U E S T RE G I S T E R S
The registers to read data back from the device (such as device status) are accessed through the
sc5312a_RegRead function. The function and parameter format for this command is
sc5312a_RegRead(deviceHandle, registerCommand, instructWord,*dataOut). Any instructions in
addition to the register call are placed into “instructWord”, and data obtained from the device is returned
via the pointer value dataOut. The set of request registers are shown in Table 3.
Table 3. Query registers.
Register Name
Register
Address
Serial
Range
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
GET_TEMPERATURE
0x20
[7:0]
Open
Open
Open
Open
Open
Open
Open
Open
GET_DEVICE_STATUS
0x21
[7:0]
Open
Open
Open
Open
Open
Open
Open
Open
USER EEPROM_READ
0x23
[7:0]
EEPROM Address [7:0]
[15:8]
EEPROM Address [15:8]
CAL_EEPROM_READ
0x24
[7:0]
EEPROM Address [7:0]
[15:8]
EEPROM Address [15:8]
Reading the Device Temperature
GET_TEMPERATURE (0x17) - Data returned by this register needs to be processed to correctly represent
data in temperature units of degrees Celsius. Data is returned in the first 14 bits [13:0]. Bit [13] is the
polarity bit indicating whether it is positive (0x0) or negative (0x1). For an ENDPOINT_IN transfer, data is
returned in 2 bytes with the MSB first. The temperature value represented in the raw data is contained in
the next 13 bits [12:0]. To obtain the temperature ADC code, the raw data should be masked (bitwise
AND’ed) with 0x1FFF, and the polarity should be masked with 0x2000. The conversion from 12 bit ADC
code to an actual temperature reading in degrees Celsius is shown below:
Positive Temperature (bit 13 is 0)
=
ADC code / 32
Negative Temperature (bit 13 is 1)
=
(ADC code –8192) / 32
It is not recommended to read the temperature too frequently, especially once the temperature of the
SC5312A has stabilized. The temperature sensor is a serial device located inside the RF module. Therefore,
like any other serial device, reading the temperature sensor requires a sending serial clock and data
commands from the processor. The process of sending clock pulses on the serial transfer line may cause
unwanted spurs on the RF signal as the serial clock could potentially modulate the externally-supplied LO
signal within the device.
Reading the Device Status
GET_DEVICE_STATUS (0x21) - This register, summarized in Table 4, returns the device status information
such as phase lock status of the PLL, current reference settings, etc. Data is contained in the first three
bytes.