Evm Power Supply Connections; Analog Input Selection Through Surface-Mount Jumpers - Texas Instruments ADS5560EVM User Manual

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Shorted 1 and 2
JP16 3.3 Va is from LDO solution
JP17 3.3 Vd is from LDO solution
ADS556x EVM also can be powered from the TSW1200EVM (optional). On the TSW1200EVM, J7 is a
6-V wall power supply connector; connect it to 6 V with JP8 (1 to 2 short) and J22 open. The
TSW1200EVM can provide a 5-V output at the J15 connector. Connect J15 to the 5-V banana jack on the
ADS556xEVM to provide a 5-V supply for the ADS556xEVM.
2.2.2 ADC Analog Input
Connectors J6 (SMA) and J8 (SMA) are used to connect the ADC with the offboard analog signal source.
At default, J8 is not installed as it is connected to GND. A single-ended analog signal, for example a sine
wave, is input to J6; then, it is converted into a differential signal through transformers T1 and T2 or
through T5 and THS4509 to the ADC's differential analog input pins. A few configurations are possible for
the analog input path. The default one is a transformer-coupling configuration through T1 and T2. The
total ratio of transformers T1 and T2 is 1:1. This configuration gives an equivalent load of 50 Ω to the
signal source in a certain frequency range, and it is a default setting from the factory. The common-mode
voltage Vcm for the analog input of ADC is provided from the ADC's CM pin. R81, C74, and R68 form a
low-pass filter to filter the glitch from the sample and hold stage.
Another analog input configuration for the ADC input is through the fully differential THS4509 amplifier. To
receive an analog signal from the THS4059, it needs to switch the connection on SJP5 and SJP3, and
SJP1 and SJP2 (see
source. The source signal is coupled by the 1:1 transformer T5 to THS4509. It is gained by 10 dB through
the amplifier and filtered by a LC low-pass or band-pass filter (users can configure it through a flexible
layout), then through transformers T1 and T2 to the ADC differential input. The ADC's CM pin provides the
common-mode voltage Vcm for the THS4509. By default, the THS4509 path is not connected to the input
of ADS556x. To use THS4509 driving the analog input of ADS556x, JP1, JP2, JP3, and JP5 need to be
reconnected from the default position as shown in the
Transformer single-ended (SE) input through J6 Short 1 to 2
OPA SE input through J6
2.2.3 ADC Clock Input
The ADC clock input is from connector J9, a single-ended (SE) clock source connector. The SE clock is
converted into a differential clock through the 1:4 transformer to the ADC clock input pins. The resistor
R29 is a 50-Ω source termination. A sine wave with a 1.5-V amplitude can be used for the evaluation test.
2.2.4 ADC Digital Output
The digital output of ADS556x is brought to the 40-pin IDC connector J5 for CMOS parallel output; it is
also brought to a high-density Samtec connector J10 for DDR LVDS output as a default setting (interface
to TSW1200). The connectors J5 and J10 can be accessed by a logic analyzer and other CMOS digital
interface directly, for example, the TSW1200 data capture board (through J10). The connector J10 can be
extended by the TI ADC breakout board to interface with the LVDS receiver including the logic analyzer. If
the CMOS parallel output is used, the U7 (SN74AVC16244DGGR) must be installed.
2.2.5 Jumper Selections for ADS556x Configuration
The EVM features different models of the ADS556x for evaluation. The model selection is based on an
internal control register setting. To access the internal control registers, the ADS556x provides three
access interfaces, parallel interface, serial interface, and parallel and serial mixed interface. The default
SLAU260 – December 2008
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Table 1. EVM Power Supply Connections
Table 2); the analog source signal is connected to J6 for a signal-ended signal
Table 2. Analog Input Selection Through Surface-Mount Jumpers
SJP3
Short 2 to 3
Shorted 2 and 3
external 3.3-V supply connects to J13
external 3.3-V supply connects to J11
Table 2.
SJP5
Short 1 to 2
Short 2 to 3
Circuit Description
Default Setting
Shorted 2 and 1
Shorted 2 and 1
SJP1 SJP2
Short 1 to 2 Short 1 to 2
Short 2 to 3 Short 2 to 3
ADS5560/62EVM 3