BOARD EVAL FOR AD7490

EVAL-AD7490CB

Manufacturer Part NumberEVAL-AD7490CB
DescriptionBOARD EVAL FOR AD7490
ManufacturerAnalog Devices Inc
EVAL-AD7490CB datasheet
 


Specifications of EVAL-AD7490CB

Number Of Adc's1Number Of Bits12
Sampling Rate (per Second)1MData InterfaceSerial
Inputs Per Adc16 Single EndedInput Range0 ~ 5 V
Power (typ) @ Conditions12.5mW @ 1MSPS, 5 VVoltage Supply SourceSingle
Operating Temperature-40°C ~ 85°CUtilized Ic / PartAD7490
Lead Free Status / RoHS StatusContains lead / RoHS non-compliant  
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FEATURES
Fast throughput rate: 1 MSPS
Specified for V
of 2.7 V to 5.25 V
DD
Low power at maximum throughput rates
5.4 mW maximum at 870 kSPS with 3 V supplies
12.5 mW maximum at 1 MSPS with 5 V supplies
16 (single-ended) inputs with sequencer
Wide input bandwidth
69.5 dB SNR at 50 kHz input frequency
Flexible power/serial clock speed management
No pipeline delays
High speed serial interface, SPI/QSPI™/MICROWIRE™/
DSP compatible
Full shutdown mode: 0.5 μA maximum
28-lead TSSOP and 32-lead LFCSP packages
GENERAL DESCRIPTION
The AD7490 is a 12-bit high speed, low power, 16-channel,
successive approximation ADC. The part operates from a single
2.7 V to 5.25 V power supply and features throughput rates up
to 1 MSPS. The part contains a low noise, wide bandwidth
track-and-hold amplifier that can handle input frequencies in
excess of 1 MHz.
The conversion process and data acquisition are controlled
using CS and the serial clock signal, allowing the device to
easily interface with microprocessors or DSPs. The input signal
is sampled on the falling edge of CS , and conversion is also
initiated at this point. There are no pipeline delays associated
with the part.
The AD7490 uses advanced design techniques to achieve very
low power dissipation at high throughput rates. For maximum
throughput rates, the AD7490 consumes just 1.8 mA with 3 V
supplies, and 2.5 mA with 5 V supplies.
By setting the relevant bits in the control register, the analog
input range for the part can be selected to be a 0 V to REF
input or a 0 V to 2 × REF
input, with either straight binary
IN
or twos complement output coding. The AD7490 features 16
single-ended analog inputs with a channel sequencer to allow a
preprogrammed selection of channels to be converted sequen-
tially. The conversion time is determined by the SCLK
Rev. C
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 that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
16-Channel, 1 MSPS, 12-Bit ADC
with Sequencer in 28-Lead TSSOP
FUNCTIONAL BLOCK DIAGRAM
AD7490
REF
IN
V
0
IN
INPUT
MUX
V
15
IN
SEQUENCER
frequency because this is also used as the master clock to
control the conversion.
The AD7490 is available in a 32-lead LFCSP and a 28-lead
TSSOP package.
PRODUCT HIGHLIGHTS
1.
The AD7490 offers up to 1 MSPS throughput rates. At
maximum throughput with 3 V supplies, the AD7490
dissipates just 5.4 mW of power.
2.
A sequence of channels can be selected, through which the
AD7490 cycles and converts.
3.
The AD7490 operates from a single 2.7 V to 5.25 V supply.
The V
function allows the serial interface to connect
DRIVE
directly to either 3 V or 5 V processor systems independent
of V
.
DD
4.
The conversion rate is determined by the serial clock,
allowing the conversion time to be reduced through the
serial clock speed increase. The part also features various
shutdown modes to maximize power efficiency at lower
IN
throughput rates. Power consumption is 0.5 μA, maximum,
when in full shutdown.
5.
The part features a standard successive approximation
ADC with accurate control of the sampling instant via a CS
input and once off conversion control.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
©2002–2009 Analog Devices, Inc. All rights reserved.
AD7490
V
DD
12-BIT
SUCCESSIVE
T/H
APPROXIMATION
ADC
SCLK
DOUT
CONTROL
LOGIC
DIN
CS
V
DRIVE
AGND
Figure 1.
www.analog.com

EVAL-AD7490CB Summary of contents

  • Page 1

    FEATURES Fast throughput rate: 1 MSPS Specified for Low power at maximum throughput rates 5.4 mW maximum at 870 kSPS with 3 V supplies 12.5 mW maximum at 1 MSPS with 5 ...

  • Page 2

    AD7490 TABLE OF CONTENTS Features .............................................................................................. 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Product Highlights ........................................................................... 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 3 Timing Specifications .................................................................. 5 Absolute Maximum Ratings ............................................................ 6 ESD Caution .................................................................................. 6 ...

  • Page 3

    SPECIFICATIONS 2 5.25 V, REF = 2 DRIVE IN −40°C to +85°C. Table 1. Parameter DYNAMIC PERFORMANCE 2 Signal-to-(Noise + Distortion) (SINAD) 2 Signal-to-Noise Ratio (SNR) Total Harmonic Distortion (THD) 2 ...

  • Page 4

    AD7490 Parameter LOGIC INPUTS Input High Voltage, V INH Input Low Voltage, V INL Input Current Input Capacitance LOGIC OUTPUTS Output High Voltage Output Low Voltage Floating State Leakage Current ...

  • Page 5

    TIMING SPECIFICATIONS ≤ REF DD DRIVE DD 1 Table 2. Timing Specifications Limit MIN MAX Parameter ...

  • Page 6

    AD7490 ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 3. Parameter V to GND GND DRIVE Analog Input Voltage to GND Digital Input Voltage to GND Digital Output Voltage to GND REF to GND ...

  • Page 7

    PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS AD7490 TOP VIEW ...

  • Page 8

    AD7490 TYPICAL PERFORMANCE CHARACTERISTICS Figure 5 shows a typical FFT plot for the AD7490 at 1 MSPS sample rate and 50 kHz input frequency. Figure 7 shows the power supply rejection ratio vs. supply ripple frequency for the AD7490. The ...

  • Page 9

    25°C A – 5.25V DD RANGE = 0V TO REF IN –60 –65 – 100Ω IN – 5Ω IN – 10Ω IN –85 10 100 ...

  • Page 10

    AD7490 TERMINOLOGY Integral Nonlinearity This is the maximum deviation from a straight line passing through the endpoints of the ADC transfer function. The end- points of the transfer function are zero scale, a point 1 LSB below the first code ...

  • Page 11

    Peak Harmonic or Spurious Noise Peak harmonic or spurious noise is defined as the ratio of the rms value of the next largest component in the ADC output spectrum ( and excluding dc) to the rms value ...

  • Page 12

    AD7490 INTERNAL REGISTER STRUCTURE CONTROL REGISTER The control register on the AD7490 is a 12-bit, write-only register. Data is loaded from the DIN pin of the AD7490 on the falling edge of SCLK. The data is transferred on the DIN ...

  • Page 13

    Table 7. Channel Selection ADD3 ADD2 Table 8. ...

  • Page 14

    AD7490 SHADOW REGISTER The Shadow register on the AD7490 is a 16-bit, write-only register. Data is loaded from the DIN pin of the AD7490 on the falling edge of SCLK. The data is transferred on the DIN line at the ...

  • Page 15

    Figure 14 shows how a sequence of consecutive channels can be converted on without having to program the Shadow register or write to the part on each serial transfer. Again, to exit this mode of operation and revert back to ...

  • Page 16

    AD7490 THEORY OF OPERATION CIRCUIT INFORMATION The AD7490 is a fast, 16-channel, 12-bit, single-supply, analog- to-digital converter. The parts can be operated from a 2 5.25 V supply. When operated from supply and provided with ...

  • Page 17

    When no amplifier is used to drive the analog input, the source impedance should be limited to low values. The maximum source impedance depends on the amount of total harmonic distortion (THD) that can be tolerated. The THD increases as ...

  • Page 18

    AD7490 TYPICAL CONNECTION DIAGRAM Figure 21 shows a typical connection diagram for the AD7490. In this setup, the AGND pin is connected to the analog ground plane of the system. In Figure 21, REF IN decoupled 2.5 V supply from ...

  • Page 19

    Reference Section An external reference source should be used to supply the 2.5 V reference to the AD7490. Errors in the reference source result in gain errors in the AD7490 transfer function and add to the specified full-scale errors of ...

  • Page 20

    AD7490 Auto Shutdown (PM1 = 0, PM0 = 1) In this mode, the AD7490 automatically enters shutdown at the end of each conversion when the control register is updated. When the part is in shutdown, the track-and-hold is in hold ...

  • Page 21

    Powering Up the AD7490 When supplies are first applied to the AD7490, the ADC may power up in any of the operating modes of the part. To ensure that the part is placed into the required operating mode, the user ...

  • Page 22

    AD7490 SERIAL INTERFACE Figure 27 shows the detailed timing diagram for serial interfacing to the AD7490. The serial clock provides the conversion clock and also controls the transfer of information to and from the AD7490 during each conversion. The CS ...

  • Page 23

    If the WEAK/ TRI bit in the control register is set to 1, instead of th returning to true three-state on the 16 DOUT line is pulled weakly to the logic level corresponding to ADD3 of the next serial transfer. ...

  • Page 24

    AD7490 MICROPROCESSOR INTERFACING The serial interface on the AD7490 allows the part to be directly connected to a range of many different microprocessors. This section explains how to interface the AD7490 with some of the more common microcontroller and DSP ...

  • Page 25

    ... EVAL-CONTROL BRD2. The EVAL-CONTROL BRD2 can be used in conjunction with the AD7490 evaluation board, as well as many other Analog Devices, Inc., evaluation boards ending in the CB designator, to demonstrate and evaluate the ac and dc performance of the AD7490. The software allows the user to perform ac (fast Fourier transform) and dc (histogram of codes) tests on the AD7490 ...

  • Page 26

    AD7490 OUTLINE DIMENSIONS PIN 1 0.15 0.05 COPLANARITY PIN 1 INDICATOR 12° MAX 1.00 0.85 0.80 SEATING PLANE 9.80 9.70 9. 4.50 4.40 4. 0.65 BSC 1.20 MAX 0.30 0.20 0.19 SEATING 0.09 ...

  • Page 27

    ... This board is a complete unit allowing control and communicate with all Analog Devices evaluation boards ending designator. To order a complete evaluation kit, you need to order the particular ADC evaluation board (for example, EVAL-AD7490CBZ), the EVAL-CONTROL-BRD2, and transformer. See the relevant evaluation board data sheet for more information. ...

  • Page 28

    AD7490 NOTES ©2002–2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D02691-0-6/09(C) Rev Page ...