Evaluation Board User Guide UG-382
Rev. A | Page 3 of 8
EVALUATION BOARD HARDWARE
POWER SUPPLIES
AGND and DGND are connected together on the board to
provide a single GND signal. To power the EVA L -AD5700-1EBZ,
supply 3.3 V between the V
CC
and GND inputs for the analog
supply of the AD5700/AD5700-1. With L5 inserted (default), this
also provides power to IOV
CC
.
LINK OPTIONS
A number of links on the evaluation board must be set for the
required operating setup before using the board. The functions
of these link options are described in detail in Table 2. The
default setup is using the on-chip reference, the crystal
oscillator, and the internal receive filter (see Table 1).
Table 1. Default Link Options
CLK_CFG1 A
CLK_CFG0 A
XTAL_EN A
FILTER_SEL B
L1 A
L2 A
REF_EN B
L5 Inserted
L6 Not inserted
L8 Inserted
Table 2. Link Functions
Link No. Function
CLK_CFG1,
CLK_CFG0,
XTAL_EN
The AD5700/AD5700-1 support numerous clocking configurations to allow a simple, low cost solution. The
AD5700/AD5700-1 can use an external crystal or ceramic resonator, a CMOS input, or an internal RC oscillator
(AD5700-1 only). The CLK_CFG0, CLK_CFG1, and XTAL_EN links configure the clock generation as follows:
XTAL_EN CLK_CFG1 CLK_CFG0 CLKOUT Description
B A A No output 3.6864 MHz CMOS clock connected at XTAL1 pin
B A B No output 1.2288 MHz CMOS clock connected at XTAL1 pin
B B A No output Internal oscillator enabled
B B B 1.2288 MHz output Internal oscillator enabled, CLKOUT enabled
A A A No output Crystal oscillator enabled
A A B 3.6864 MHz output Crystal oscillator enabled, CLKOUT enabled
A B A 1.8432 MHz output Crystal oscillator enabled, CLKOUT enabled
A B B 1.2288 MHz output Crystal oscillator enabled, CLKOUT enabled
FILTER_SEL, L1, L2 These link options set whether the internal or external receive band-pass filter is used at the HART input.
Setting FILTER_SEL to Position B and L1 and L2 to Position A sets the board to use the internal receive band-pass filter.
Setting FILTER_SEL to Position A and L1 and L2 to Position B sets the board to use the external receive band-pass filter.
REF_EN This sets whether the internal or an external reference is used.
Position A—disables the internal reference, and a buffered external 2.5 V reference source must be applied at REF.
Position B—enables the internal 1.5 V reference and buffer.
DUPLEX Allows the modulator and demodulator of the AD5700/AD5700-1 to be enabled at the same time.
Position A—the AD5700/AD5700-1 operate in half-duplex operation (controlled by
RTS
).
Position B—the AD5700/AD5700-1 operate in full duplex operation, with the modulator and demodulator of the
AD5700/AD5700-1 enabled at the same time.
L5 Allows V
CC
to be connected directly to IOV
CC
.
Inserted—V
CC
is connected to IOV
CC
.
Not inserted—V
CC
is disconnected from IOV
CC
.
L6 Do not insert this link.
L8 This link must be inserted.
