Preliminary Technical Data
EVAL-AD5934EB
Rev. PrC | Page 3 of 32
EVALUATION BOARD HARDWARE
TERMINAL BLOCK FUNCTIONS
Table 1. Terminal Block Function Descriptions
Pin Name
Description
J1
USB
USB Hub for the Evaluation Board.
J2-1
DVDD-5V
Digital Circuitry Supply Connection to Pin 9. This connector is decoupled to the digital ground plane via
standard 0.1 μF and 10 μF suppression capacitors. This connector also supplies the high performance, 16 MHz,
surface-mount crystal with the required operating supply voltage.
J2-2 DGND
Digital Ground Connection. This connector is decoupled to J2-1 using standard 0.1 μF and 10 μF suppression
capacitors. The digital ground plane is connected to the analog ground plane at a single point underneath the board.
J3 -1
VDD-AMP
Single-Supply Amplifier Connection. There is a facility to place a single-supply operational amplifier (user
supplied) on the output voltage pin (VOUT) of the AD5934. This terminal block is a connection to the single-
supply positive rail of the operation amplifier.
J3-2 AGND
Analog Ground Connection. This connector is decoupled to J3-1 using standard 0.1 μF and 10 μF suppression
capacitors. The analog ground plane is connected to the digital ground plane at a single point underneath the board.
J4-1 AVDD-REF
Analog Reference Input Supply to Pin 11. This connector is decoupled to J4-2 via standard 0.1 μF and 10 μF
suppression capacitors.
J4-2 AGND
Analog Ground Connection. This connector is decoupled to J4-1 using standard 0.1 μF and 10 μF suppression
capacitors. The analog ground plane is connected to the digital ground plane at a single point underneath the board.
J5-1 AVDD-SIG
Analog Circuit Input Supply to Pin 10. This connector is decoupled to J5-2 via standard 0.1 μF and 10 μF
suppression capacitors.
J5-2 AGND
Analog Ground Connection. This connector is decoupled to J5-1 using standard 0.1 μF and 10 μF suppression
capacitors. The analog ground plane is connected to the digital ground plane at a single point underneath the board.
J6-1 VDD-REF
Power Supply Connection for On-Board Reference. This provides a connection to the power supply pin of the
on-board reference at U4 (ADR423).
J6-2 AGND
Analog Ground Connection. This connector is decoupled to J6-1 using standard 0.1 μF and 10 μF suppression
capacitors. The analog ground plane is connected to the digital ground plane at a single point underneath the board.
LINK FUNCTIONS
Table 2. Link Function Descriptions
Link No.
Function
LK1
Link 1 is used to connect the output of the optional user-supplied external operational amplifier (U1) to the VOUT SMB
connector (see Figure 1). This op amp can be used to amplify/buffer the output excitation voltage from the AD5934.
Link 1 is used in conjunction with Link 6 and Link 2. When Link 1 and Link 2 are inserted, Link 6 should be removed and vice
versa. The output of the AD5934 either can be connected to the external op amp by removing Link 6 (LK6) and inserting Link 1
and Link 2 (LK1 and LK2) and then routing to SMB VOUT or can be directly routed to SMB VOUT by removing Link 1 and Link 2
(LK1 and LK2) and inserting Link 6 (LK6). Therefore, the signal path is determined by suitably inserting/removing Link 1, Link 2,
and Link 6.
•
When Link 1 is inserted, the output of the user-supplied amplifier (for example, AD820 or OP196) is applied to the SMB
output, VOUT. When Link 1 and Link 2 are inserted, Link 6 should be removed to connect the noninverting op amp input
in series with the AD5934 output pin.
•
When Link 1 is removed, the output of the user-supplied amplifier is no longer applied to the SMB output, VOUT. When Link 1
and Link 2 are removed, Link 6 should be inserted to connect the AD5934 output pin directly to the VOUT SMB connector.
LK2
This link option is used to connect the output excitation signal from Pin 6 (VOUT) of the AD5934 to the noninverting terminal
of the user-supplied operational amplifier. This link is used in conjunction with Link 1 and Link 6. When Link 1 and Link 2 are
inserted, Link 6 should be removed and vice versa.
•
When Link 2 (LK2) is inserted, the output of the AD5934 excitation voltage pin (Pin 6) is applied to the noninverting
terminal (Pin 3 of U1) of the user-supplied operational amplifier.
•
When Link 2 is removed, the output of the AD5934 excitation voltage pin (Pin 6) is no longer applied to the noninverting
terminal (Pin 3 of U1) of the user-supplied operational amplifier, but is routed directly to the SMB VOUT if Link 6 (LK6) is
inserted.
LK3
The AD5934 must provide an external clock signal applied to Pin 8 (MCLK).The user can use a high performance, 16 MHz,
surface-mount crystal that is supplied with the evaluation board (Y2). Alternatively, the user can provide a clock signal by
applying a system clock signal through the CLK1 SMB connector. To do this, remove Link 12 (LK12) and insert Link 3 (LK3). As a
result, the clock signal applied at CLK1 will be connected to the clock pin (MCLK).