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LMH2832EVM-50
User Manual
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Texas Instruments LMH2832EVM-50, LP8731-Q1 User Manual

User's Guide
SLOU454–June 2016
LMH2832EVM-50 Evaluation Module
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Contents
1 Features....................................................................................................................... 2
2 EVM Specifications.......................................................................................................... 3
3 Evaluation Board Setup Block Diagram .................................................................................. 3
4 Setup Procedure............................................................................................................. 4
4.1 Connect EVM to a 5-V Bench Power Supply ................................................................... 4
4.2 Connect EVM to the External Signal Source at the Input ..................................................... 4
4.3 Connect EVM to the External Test Equipment at the Output................................................. 4
4.4 PD (Power Down) Input............................................................................................ 4
4.5 Connect EVM to the PC and LMH2832 EVM GUI Installation................................................ 5
5 Amplifier Device Register Configuration .................................................................................. 5
5.1 LMH2832 EVM GUI ................................................................................................ 6
5.2 Low Level View ..................................................................................................... 7
6 Evaluation Troubleshooting................................................................................................. 8
7 LMH2832 EVM Schematic, Layer Prints, and Bill of Materials ........................................................ 9
7.1 Schematic............................................................................................................ 9
7.2 Layer Prints ........................................................................................................ 11
7.3 Bill of Materials .................................................................................................... 19
1 LMH2832EVM Board........................................................................................................ 2
2 LMH2832 Evaluation Board Setup Block Diagram...................................................................... 3
3 LMH2832 EVM GUI Front Page ........................................................................................... 6
4 Low Level View Tab......................................................................................................... 7
5 Schematic - Analog.......................................................................................................... 9
6 Schematic - Digital ......................................................................................................... 10
7 Top Layer ................................................................................................................... 11
8 Layer 2 Ground Plane ..................................................................................................... 12
9 Layer 3 GND Plane ........................................................................................................ 13
10 Layer 4 GND Plane ........................................................................................................ 14
11 Layer 5 V+ Plane........................................................................................................... 15
12 Layer 6 Ground Plane ..................................................................................................... 16
13 Layer 7 GND Plane ........................................................................................................ 17
14 Bottom Layer................................................................................................................ 18
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List of Figures
List of Tables
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LMH2832EVM-50 Evaluation Module
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Features
1 EVM Specifications.......................................................................................................... 3
2 LMH2832 Default SPI Register Map ...................................................................................... 5
3 LMH2832 GUI Tab Descriptions........................................................................................... 6
4 Low Level View Controls ................................................................................................... 7
5 LMH2832EVM Bill of Materials........................................................................................... 19
1 Features
The key features of this EVM include:
• Configured for 5-V single-supply operation
• Designed for AC-coupled, single-ended, 50-Ω input, and output connection
• Interface to the inputs and outputs using SMA connectors
• USB connector and FTDI USB-to-SPI bus translator chip to successfully program the DVGA gain
registers
Figure 1 shows the LMH2832EVM board.
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LMH2832EVM-50 Evaluation Module
Figure 1. LMH2832EVM Board
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USB
½ LMH2832
5-V Bench
Power Supply
5 V GND
40 Q
40 Q
SPI
LMH2832 EVM
Low-Noise
Signal Generator
Spectrum Analyzer
(V+)
Band-Pass
Filter
0.1 µF
0.1 µF
ETC1-1-13T
(1:1, Zo = 50 Ÿ)
MABA011038
(1:3, Zo = 50 Ÿ)
0.1 µF
0.1 µF
SMA
SMA
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2 EVM Specifications
Table 1 lists the EVM specifications.
Table 1. EVM Specifications
Parameter Value
V
Single-supply voltage range (V– = Ground) 4.5 V to 5.25 V
s
GND Ground reference pins Tied to GND or 0 V PDA
or
Power down (PD) input voltage GND to V
PDB I
Supply current with both channels enabled approximately 204 mA
s
I
Input voltage Vs±, Max
IN
3 Evaluation Board Setup Block Diagram
The following sections help in setting up the LMH2832 evaluation board hardware and software required to program the internal registers of the LMH2832.
Figure 2 illustrates the LMH2832 evaluation board setup block diagram.
EVM Specifications
s
Figure 2. LMH2832 Evaluation Board Setup Block Diagram
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Setup Procedure
4 Setup Procedure
This section describes the hardware setup procedure and the installation of the software to program the LMH2832 registers.
4.1 Connect EVM to a 5-V Bench Power Supply
1. Before making connections from the bench power supply to the evaluation board supply pin connector,
set the bench power supply to 5 V, and switch the bench power supply OFF.
2. While the supplies are turned OFF, connect the evaluation board power supply pins (V+ and GND) to
the bench power supply of 5 V and GND, as shown in Figure 2, using a low-noise bench power supply.
3. Turn ON the bench supplies after the power supply connections have been made. The LMH2832
evaluation board should read an approximate DC current of 204 mA for 5-V single supply with both the LMH2832 channels enabled. Input and output pins should be biased to the mid-supplies as specified in the LMH2832 data sheet (SBOS709) for proper operation.
4.2 Connect EVM to the External Signal Source at the Input
1. The LMH2832EVM-50 evaluation board provides the customer flexibility in testing at different input
frequencies using on-board input and output baluns as shown in Figure 2.
2. It is recommended to use 6-dB attenuator pads at the input while connecting a 50-Ω signal source to
the LMH2832EVM-50 evaluation board SMA inputs.
3. TI recommends using a low pass or band pass filter in-between the signal source and the evaluation
board while measuring the harmonic distortion or inter-modulation distortion products.
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4.3 Connect EVM to the External Test Equipment at the Output
1. The LMH2832EVM-50 evaluation board has SMA connectors at the output and can be directly
connected to 50-Ω test equipment as shown in Figure 2.
2. While connecting the evaluation board output to an oscilloscope, make sure the oscilloscope is set in a
50-Ω termination for the correct voltage reading on the oscilloscope.
4.4 PD (Power Down) Input
1. The LMH2832EVM has jumpers (J6 and J8) that allow the individual channels of the amplifier to be
manually disabled. The LMH2832 EVM consumes less than 9 mA of supply current with both the LMH2832 channels disabled.
2. The PDA and PDB SMA input connector facilitates driving the LMH2832 PDA and PDB pins with a
high-speed signal source. Note that the PD SMA input connector should to be terminated on-board with 50 Ω to GND (R11 and R12) so as to provide high-frequency termination for signals from a 50-Ω pulse generator.
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4.5 Connect EVM to the PC and LMH2832 EVM GUI Installation
The LMH2832 EVM GUI is used to control the LMH2832 EVM. It must be used to properly configure the LMH2832 device.
1. Download the LMH2832 EVM GUI (SLOC338) from the TI website.
2. Extract the files from the zip file.
3. Run setup.exe and follow the installation prompts.
4. Connect the LMH2832EVM to the PC using a mini-USB cable.
5. Open the LMH2832 EVM GUI by going to Start Menu → All Programs → Texas Instruments →
LMH2832 EVM GUI.
6. Verify that the green USB Status indicator is lit in the top right corner of the GUI. If it is not lit, click the
Reconnect USB button and check the USB Status indicator again. If it is still not lit, then verify the EVM is connected to the computer through the included mini-USB cable.
7. Follow the instructions in Section 5: Amplifier Device Register Configuration to correctly use the GUI to
program the LMH2832 device registers.
8. The DVGA register address and configuration values are found in the LMH2832 device data sheet
(SBOS709).
5 Amplifier Device Register Configuration
The LMH2832 channels are programmable via the serial programming interface (SPI) bus accessible through the FTDI USB-to-SPI converter chip located on the EVM. A GUI is provided to write instructions on the bus and program the registers of the LMH2832.
The LMH2832 individual channel gain can be controlled from –9 dB to 30 dB in 1-dB steps using register address 5h and 7h for channels A and B, respectively. The amplifier is programmed to the maximum gain (30 dB) when a value 0h is written to the gain control registers 5h and 7h, whereas a value 27h written to the gain control registers programs the device to the minimum gain (–9 dB) setting. Table 2 shows the default LMH2832 SPI register map on power up. For more information about the registers in the LMH2832, see the LMH2832 data sheet (SBOS709).
Setup Procedure
Table 2. LMH2832 Default SPI Register Map
Address (A[6:0], Hex) R/W Register Default
0 R Revision ID B3h 1 R Product ID 23h 2 R/W Software Reset 00h 3 R/W Power-down 00h 4 R/W Channel A Bias Control 20h 5 R/W Channel A Gain Control 14h 6 R/W Channel B Bias Control 20h 7 R/W Channel B Gain Control 14h
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Amplifier Device Register Configuration
5.1 LMH2832 EVM GUI
The software GUI allows for full register programming control of the LMH2832. Figure 3 shows the front page of the LMH2832 EVM GUI as it should be seen upon opening the GUI. Descriptions for each of the tabs of the GUI are shown in Table 3.
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Tab Description
High Level View
Low Level View
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LMH2832EVM-50 Evaluation Module
Enables control of the LMH2832 features. None of these controls need to be touched for basic operation. Instead, use the Low Level View tab to load configuration files.
Allows write and read access to all device registers. Also allows loading and saving of configuration files. The device configurations can be saved from this tab for use in the user’s system. See Figure 4 for more information.
Figure 3. LMH2832 EVM GUI Front Page
Table 3. LMH2832 GUI Tab Descriptions
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Register Map
Register Field
Descriptions
Register Data
Generic
Read/Write
Configuration buttons
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5.2 Low Level View
The Low Level View tab, shown in Figure 4, allows configuration of the devices at the bit and field level. At any time, the controls described in Table 4 may be used to configure or read from the device.
Amplifier Device Register Configuration
Control Description
Register Map
Write Register button Read Register button Read from the register highlighted in the Register Map and display the results in the Value column. Read All button Load Config button Load a configuration file from disk and write the registers in the file.
Save Config button Save a configuration file to disk that contains the current register configuration. Register Data Cluster Manipulate individual accessible bits of the register highlighted in the Register Map. Generic Read/Write
Register buttons
Displays the devices on the EVM, registers for those devices, and the states of the registers:
• Selecting a register field allows bit manipulation in the Register Data section.
• The Value column shows the value of the register at the time the GUI was last updated due to a
Write to the register highlighted in the Register Map with the value in the Write Data field. This button must be clicked after changing bits in the register data section.
Read from all registers in the Register Map and display the current state of hardware. Also updates the controls in the other tabs.
Perform a generic read or write command to the device shown in the Block drop-down box using the Address and Write Data information.
read or write event.
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Figure 4. Low Level View Tab
Table 4. Low Level View Controls
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Evaluation Troubleshooting
6 Evaluation Troubleshooting
Issue Troubleshoot
Problem reading or writing the LMH2832 device using the LMH2832 EVM GUI:
Low supply current: See if one of the device channels is disabled by the PDA or
No supply current: See if the power supply cable connections are connected
High supply current: The reverse supply protection diodes may be conducting.
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Verify that the green USB Status indicator is lit in the top right corner of the GUI. If it is not lit, click the Reconnect USB button and check the USB Status indicator again. If it is still not lit, then verify the EVM is connected to the computer through the included mini-USB cable.
Check to see whether the connectors to power supply pins of the LMH2832 EVM are connected properly and turned ON. The nominal supply current for the LMH2832EVM for 5-V supply is approx 204-mA with both the channels enabled.
PDB jumper. Also, check to see if the power supply is set to the right voltage.
and the power switch of the source is turned ON.
Turn off the power switch and make sure the positive supply is connected to the proper pin. Turn the power back on to see if the correct supply current is recorded.
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