EVAL-AD7492CBZ

EVAL-AD7492CBZ Datasheet

= EvaluationBoardfor12-bithighspeed, low power, successive-approximation ADC EVAL-AD7492CB

Part	Datasheet
EVAL-AD7492CBZ	EVAL-AD7492CBZ (pdf)

PDF Datasheet Preview
= EvaluationBoardfor12-bithighspeed, low power, successive-approximation ADC EVAL-AD7492CB Full-Featured Evaluation Board for the AD7492 EVAL-CONTROL BRD2 Compatible Stand Alone Capability On-Board Analog Buffering and Reference Optional On-Board Analog Bias-Up Circuit Various Linking Options PC Software for Control and Data Analysis when used with EVAL-CONTROL BRD2 Interfacing to this board is through a 96-way connector. This 96-way connector is compatible with the EVAL-CONTROL BRD2 which is also available from Analog Devices. External sockets are provided for the CONVST input and the VIN inputs. OPERATING THE AD7492 EVALUATION BOARD Power Supplies When using this evaluation board with the EVAL-CONTROL BRD2, all supplies are provided from the EVALCONTROL BRD2 through the 96 way connector. INTRODUCTION This Technical Note describes the evaluation board for the AD7492 12-bit, high speed, low power, internal reference and clock, successive approximation A/D converter that operates from a single V to V supply. Full data on the AD7492 is available in the AD7492 data sheet available from Analog Devices and should be consulted in conjunction with this Technical Note when using the Evaluation Board. On-board components include an AD780 which is a pin programmable V or +3 V ultra high precision bandgap reference, two AD797 op-amps used to buffer the analog input, and an OP07 op-amp used to buffer the DC bias voltage applied to the optional analog input bias-up circuit. There are various link options which are explained in detail on page When using the board as a stand alone unit, external supplies must be provided. This evaluation board has five power supply inputs VDD, AGND, VSS, VDRIVE and DGND. +5 V must be connected to the VDD input to supply the AVDD and DVDD pins on the AD7492, the AD780 voltage reference, the positive supply pin of all three op-amps and the digital control logic. 0 V is connected to the AGND input. -5 V must be connected to the VSS input to supply the negative supply pins on all three op-amps. The VDRIVE input can be used to provide an external voltage for the output drivers on the AD7492. If an external VDRIVE is supplied, it is referenced to the DGND input which should be tied to 0 V. The supplies are decoupled to the relevant ground plane with 47µF tantalum and 0.1µF multilayer ceramic capacitors at the point where they enter the board. The supply pins of the op-amps and FUNCTIONAL BLOCK DIAGRAM Unipolar Ain Buffe r AD7492 ADC 96 Pin Eval-Control Board Interface Bipolar Ain B i a s-u p buffer External Reference Vin Ref Out Data Bus Control Lines Power Supply Circuit Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A. Tel 617/329-4700 Fax 617/326-8703 EVAL-AD7492CB reference are also decoupled to AGND with a 10µF tantalum and a 0.1µF ceramic capacitor. The AD7492 AVDD supply pin is decoupled to AGND with 10uF tantalum and 0.1µF multilayer ceramic capacitors. The AD7492 DVDD and VDRIVE pins are decoupled to AGND with 10uF tantalum capacitors and to DGND with 0.1µF multilayer ceramic capacitors. Extensive ground planes are used on this board to minimize the effect of high frequency noise interference. There are two ground planes, AGND and DGND. These are connected at one location close to the AD7492. Analog Input Section The analog input section of this evaluation board accommodates unipolar and bipolar signals. Unipolar signals within the AD7492 analog input signal range of 0 V - V are connected via SK1. They are then buffered by the on-board buffer before being applied to the VIN pin of the AD7492. Bipolar signals are connected via SK3 and are biased up by the on-board biasup buffer circuit before being applied to the VIN pin of the AD7492. The input impedence of the bias-up circuit is which is determined by the value of R7. The input impedence may be modified by removing/changing the value of R7. To obtain optimum performance from this evaluation board the use of an impedence matched, passive filter is recommended before the analog signal is applied to the evaluation board. For example, when using a 100KHz input tone, a 100KHz filter from TTE part number KC5-100K-15K-50/50-720B is suitable. R13 Potentiometer 50Kohm This variable resistor is used to trim the DC bias voltage applied to the optional analog input bias-up circuit. This bias voltage is factory preset to V which biases a bipolar signal to swing around the midpoint of the analog input range 0 - V . If any adjustment is required, the user can use the histogram window in the eval-board software to analyze the DC voltage variation while adjusting the trim pot. To view this properly, an analog input signal should not be applied to the board. Under normal operation this pot should not be adjusted as it is preset for optimum performance. LINK AND SWITCH OPTIONS There are 12 link options which must be set for the required operating setup before using the evaluation board. The functions of these options are outlined below. Link No. Function. This link is used to select the DC bias voltage to be applied to the optional Vin bias-up circuit. If the user is using the bias-up circuit, this link must be inserted which will apply the V reference voltage to the bias-up circuit. This causes a bipolar signal applied to the bipolar vin input socket to be biased up around V before it is applied to the AD7492 VIN pin. - see also LK10 below . When this link is in position "A" the bias-up circuit is supplied by the AD7492 internal reference. When this link is in position "B" the bias-up circuit is supplied by the AD780 external reference. If the bias up circuit is not being used this link should be removed. This link must be in position "A" if external power supplies are being used. In this position the control logic is being powered by the voltage applied to the VDD input. When power is being supplied from the EVAL-CONTROL BRD2, this link can be moved to position "B" if the user wants to drive the control logic from a separate +5 V which is generated on the EVAL-CONTROL BRD2. This link option selects the sleep mode that the AD7492 can be put into. When this link is in position "A" the part goes into full sleep when low power operation is selected. When this link is in position "B" the part goes into partial sleep when low power operation is selected. This link option selects the source of the CONVST input. When this link is in position "A" the CONVST input is provided by the EVAL-CONTROL BRD2. When this link is in position "B" the CONVST input is provided via the external socket, SK2. This link option selects the source of the RD input. When this link is in position "A" the RD input is provided by the EVAL-CONTROL BRD2. When this link is in position "B" the RD input is tied to GND. This link option selects the source of the CS input. When this link is in position "A" the CS input is provided by the EVAL-CONTROL BRD2. When this link is in position "B" the CS input is tied to GND.

PDF Datasheet Preview

= EvaluationBoardfor12-bithighspeed, low power, successive-approximation ADC EVAL-AD7492CB

Full-Featured Evaluation Board for the AD7492 EVAL-CONTROL BRD2 Compatible Stand Alone Capability On-Board Analog Buffering and Reference Optional On-Board Analog Bias-Up Circuit Various Linking Options PC Software for Control and Data Analysis when used with EVAL-CONTROL BRD2

Interfacing to this board is through a 96-way connector. This 96-way connector is compatible with the EVAL-CONTROL BRD2 which is also available from Analog Devices. External sockets are provided for the CONVST input and the VIN inputs.

OPERATING THE AD7492 EVALUATION BOARD

Power Supplies When using this evaluation board with the EVAL-CONTROL BRD2, all supplies are provided from the EVALCONTROL BRD2 through the 96 way connector.

INTRODUCTION This Technical Note describes the evaluation board for the AD7492 12-bit, high speed, low power, internal reference and clock, successive approximation A/D converter that operates from a single V to V supply. Full data on the AD7492 is available in the AD7492 data sheet available from Analog Devices and should be consulted in conjunction with this Technical Note when using the Evaluation Board.

On-board components include an AD780 which is a pin programmable V or +3 V ultra high precision bandgap reference, two AD797 op-amps used to buffer the analog input, and an OP07 op-amp used to buffer the DC bias voltage applied to the optional analog input bias-up circuit. There are various link options which are explained in detail on page

When using the board as a stand alone unit, external supplies
must be provided. This evaluation board has five power supply inputs VDD, AGND, VSS, VDRIVE and DGND. +5 V must be connected to the VDD input to supply the AVDD and DVDD pins on the AD7492, the AD780 voltage reference, the positive supply pin of all three op-amps and the digital
control logic. 0 V is connected to the AGND input. -5 V must be connected to the VSS input to supply the negative supply pins on all three op-amps. The VDRIVE input can be used to provide an external voltage for the output drivers on the

AD7492. If an external VDRIVE is supplied, it is referenced to the DGND input which should be tied to 0 V. The supplies are decoupled to the relevant ground plane with 47µF tantalum
and 0.1µF multilayer ceramic capacitors at the point where they enter the board. The supply pins of the op-amps and

FUNCTIONAL BLOCK DIAGRAM

Unipolar Ain

Buffe r

AD7492 ADC
96 Pin Eval-Control Board Interface

Bipolar Ain

B i a s-u p buffer

External Reference

Vin Ref Out

Data Bus Control Lines

Power Supply Circuit

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.

Tel 617/329-4700

Fax 617/326-8703

EVAL-AD7492CB
reference are also decoupled to AGND with a 10µF tantalum and a 0.1µF ceramic capacitor. The AD7492 AVDD supply pin is decoupled to AGND with 10uF tantalum and 0.1µF multilayer ceramic capacitors. The AD7492 DVDD and VDRIVE pins are decoupled to AGND with 10uF tantalum capacitors and to DGND with 0.1µF multilayer ceramic capacitors.

Extensive ground planes are used on this board to minimize the effect of high frequency noise interference. There are two ground planes, AGND and DGND. These are connected at one location close to the AD7492.

Analog Input Section The analog input section of this evaluation board accommodates unipolar and bipolar signals. Unipolar signals within the AD7492 analog input signal range of 0 V - V are connected via SK1. They are then buffered by the on-board buffer before being applied to the VIN pin of the AD7492. Bipolar signals are connected via SK3 and are biased up by the on-board biasup buffer circuit before being applied to the VIN pin of the AD7492. The input impedence of the bias-up circuit is which is determined by the value of R7. The input impedence may be modified by removing/changing the value of R7. To obtain optimum performance from this evaluation board the use of an impedence matched, passive filter is recommended before the analog signal is applied to the evaluation board. For example, when using a 100KHz input tone, a 100KHz filter from TTE part number KC5-100K-15K-50/50-720B is suitable.

R13 Potentiometer 50Kohm This variable resistor is used to trim the DC bias voltage applied to the optional analog input bias-up circuit. This bias voltage is factory preset to V which biases a bipolar signal to swing around the midpoint of the analog input range 0 - V . If any adjustment is required, the user can use the histogram window in the eval-board software to analyze the DC voltage variation while adjusting the trim pot. To view this properly, an analog input signal should not be applied to the board. Under normal operation this pot should not be adjusted as it is preset for optimum performance.

LINK AND SWITCH OPTIONS There are 12 link options which must be set for the required operating setup before using the evaluation board. The functions of these options are outlined below.

Link No.

Function.

This link is used to select the DC bias voltage to be applied to the optional Vin bias-up circuit. If the user is using the bias-up circuit, this link must be inserted which will apply the V reference voltage to the bias-up circuit. This causes a bipolar signal applied to the bipolar vin input socket to be biased up around V before it is applied to the AD7492 VIN pin. - see also LK10 below . When this link is in position "A" the bias-up circuit is supplied by the AD7492 internal reference. When this link is in position "B" the bias-up circuit is supplied by the AD780 external reference. If the bias up circuit is not being used this link should be removed.

This link must be in position "A" if external power supplies are being used. In this position the control logic is being powered by the voltage applied to the VDD input. When power is being supplied from the EVAL-CONTROL BRD2, this link can be moved to position "B" if the user wants to drive the control logic from a separate +5 V which is generated on the EVAL-CONTROL BRD2.

This link option selects the sleep mode that the AD7492 can be put into. When this link is in position "A" the part goes into full sleep when low power operation is selected. When this link is in position "B" the part goes into partial sleep when low power operation is selected.

This link option selects the source of the CONVST input. When this link is in position "A" the CONVST input is provided by the EVAL-CONTROL BRD2. When this link is in position "B" the CONVST input is provided via the external socket, SK2.

This link option selects the source of the RD input. When this link is in position "A" the RD input is provided by the EVAL-CONTROL BRD2. When this link is in position "B" the RD input is tied to GND.

This link option selects the source of the CS input. When this link is in position "A" the CS input is provided by the EVAL-CONTROL BRD2. When this link is in position "B" the CS input is tied to GND.

More datasheets: 50738361531600F | AO4946 | MSA-0270 | AK670/3-2-R | A61-113-200P4C3 | A61-114-200P4C3 | A61-112-200P4C3 | A61-114-233P4C3 | A61-112-233P4C3 | A61-113-233P4C3

Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived EVAL-AD7492CBZ Datasheet file may be downloaded here without warranties.

Datasheet ID: EVAL-AD7492CBZ 517904