AD7495BRZ

Manufacturer Part NumberAD7495BRZ
DescriptionADC Single SAR 1MSPS 12-Bit Serial 8-Pin SOIC N
ManufacturerAnalog Devices Inc
AD7495BRZ datasheet
 


Specifications of AD7495BRZ

Package8SOIC NResolution12 Bit
Sampling Rate1000 KSPSArchitectureSAR
Number Of Analog Inputs1Digital Interface TypeSerial (SPI, QSPI, Microwire)
Input TypeVoltageSignal To Noise Ratio68 dB
Polarity Of Input VoltageUnipolarNumber Of Bits12
Sampling Rate (per Second)1MData InterfaceDSP, MICROWIRE™, QSPI™, Serial, SPI™
Number Of Converters1Power Dissipation (max)10.5mW
Voltage Supply SourceSingle SupplyOperating Temperature-40°C ~ 85°C
Mounting TypeSurface MountPackage / Case8-SOIC (0.154", 3.90mm Width)
Lead Free Status / RoHS StatusLead free / RoHS Compliant  
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FEATURES AND APPLICATIONS
Fast throughput rate: 1 MSPS
Specified for V
of 2.7 V to 5.25 V
DD
Low power:
4.5 mW max at 1 MSPS with 3 V supplies
10.5 mW max at 1 MSPS with 5 V supplies
Wide input bandwidth:
68 dB SNR at 300 kHz input frequency
Flexible power/serial clock speed management
No pipeline delays
High speed serial interface:
SPI™-/QSPI™-/MICROWIRE™-/DSP-compatible
On-board reference: 2.5 V (AD7495 only)
Standby mode: 1 μA max
8-lead MSOP and SOIC packages
Battery-powered systems
Personal digital assistants
Medical instruments
Mobile communications
Instrumentation and control systems
Data acquisition systems
Optical sensors
GENERAL DESCRIPTION
1
The AD7475/AD7495
are 12-bit, high speed, low power,
successive-approximation ADCs that operate from a single
2.7 V to 5.25 V power supply with throughput rates up to
1 MSPS. They contain a low noise, wide bandwidth track-and-
hold amplifier that can handle input frequencies above 1 MHz.
The conversion process and data acquisition are controlled
using CS and the serial clock, allowing the devices to interface
with microprocessors or DSPs. The input signal is sampled on
the falling edge of CS and conversion is initiated at this point.
The conversion time is determined by the SCLK frequency.
There are no pipeline delays associated with the part.
The AD7475/AD7495 use advanced design techniques to
achieve very low power dissipation at high throughput rates.
With 3 V supplies and a 1 MSPS throughput rate, the AD7475
consumes just 1.5 mA, while the AD7495 consumes 2 mA.
With 5 V supplies and 1 MSPS, the current consumption is
2.1 mA for the AD7475 and 2.6 mA for the AD7495.
The analog input range for the parts is 0 V to REF IN. The 2.5 V
reference for the AD7475 is applied externally to the REF IN
pin, while the AD7495 has an on-board 2.5 V reference.
1
Protected by U.S. Patent No. 6,681,332
Rev. B
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.
1 MSPS,12-Bit ADCs
AD7475/AD7495
FUNCTIONAL BLOCK DIAGRAMS
V
DD
12-BIT
T/H
V
IN
SUCCESSIVE
APPROXIMATION
REF IN
ADC
CONTROL
LOGIC
AD7475
GND
V
DD
12-BIT
T/H
V
IN
SUCCESSIVE
APPROXIMATION
ADC
REF OUT
BUF
CONTROL
LOGIC
2.5V
REFERENCE
AD7495
GND
Figure 1.
PRODUCT HIGHLIGHTS
1.
The AD7475 offers 1 MSPS throughput rates with 4.5 mW
power consumption.
2.
Single-supply operation with V
DRIVE
AD7475/AD7495 operate from a single 2.7 V to 5.25 V
supply. The V
function allows the serial interface
DRIVE
to connect directly to either 3 V or 5 V processor systems
independent of V
.
DD
3.
Flexible power/serial clock speed management. The con-
version rate is determined by the serial clock, allowing the
conversion time to be reduced through the serial clock
speed increase. The parts also feature shutdown modes to
maximize power efficiency at lower throughput rates. This
allows the average power consumption to be reduced while
not converting. Power consumption is 1 μA when in full
shutdown.
4.
No pipeline delay. The parts feature 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
© 2005 Analog Devices, Inc. All rights reserved.
SCLK
SDATA
CS
V
DRIVE
SCLK
SDATA
CS
V
DRIVE
function. The
www.analog.com

AD7495BRZ Summary of contents

  • Page 1

    FEATURES AND APPLICATIONS Fast throughput rate: 1 MSPS Specified for Low power: 4.5 mW max at 1 MSPS with 3 V supplies 10.5 mW max at 1 MSPS with 5 V supplies ...

  • Page 2

    AD7475/AD7495 TABLE OF CONTENTS AD7475 Specifications..................................................................... 3 AD7495 Specifications..................................................................... 5 Timing Specifications....................................................................... 7 Timing Example 1 ........................................................................ 8 Timing Example 2 ........................................................................ 8 Absolute Maximum Ratings............................................................ 9 ESD Caution.................................................................................. 9 Pin Configuration and Function Descriptions........................... 10 Terminology .................................................................................... 11 Typical ...

  • Page 3

    AD7475 SPECIFICATIONS 5.25 V, REF DRIVE Table 1. Parameter DYNAMIC PERFORMANCE Signal-to-Noise and Distortion Ratio (SINAD) Total Harmonic Distortion (THD) Peak Harmonic ...

  • Page 4

    AD7475/AD7495 Parameter POWER REQUIREMENTS DRIVE Normal Mode (Static) Normal Mode (Operational) Partial Power-Down Mode Partial Power-Down Mode Full Power-Down Mode Power Dissipation Normal Mode (Operational) Partial Power-Down (Static) Full Power-Down 1 Temperature ranges for ...

  • Page 5

    AD7495 SPECIFICATIONS DRIVE Table 2. Parameter DYNAMIC PERFORMANCE Signal-to-Noise and Distortion (SINAD) Total Harmonic Distortion (THD) Peak Harmonic or Spurious Noise (SFDR) Intermodulation Distortion ...

  • Page 6

    AD7475/AD7495 Parameter POWER REQUIREMENTS DRIVE I DD Normal Mode (Static) Normal Mode (Operational) Partial Power-Down Mode Partial Power-Down Mode Full Power-Down Mode 3 Power Dissipation Normal Mode (Operational) Partial Power-Down (Static) Full Power-Down 1 Temperature ranges for ...

  • Page 7

    TIMING SPECIFICATIONS 5.25 V, REF IN = 2.5 V (AD7475 DRIVE Table 3. Parameter Limit MIN SCLK 20 t ...

  • Page 8

    AD7475/AD7495 TIMING EXAMPLE 1 With MHz and a throughput of 1 MSPS, the cycle SCLK time 12.5(1 μs. With t 2 SCLK ACQ is 365 ns. The 365 ns ...

  • Page 9

    ABSOLUTE MAXIMUM RATINGS T = 25°C unless otherwise noted. A Table 4. Parameters V to GND GND DRIVE Analog Input Voltage to GND Digital Input Voltage to GND DRIVE DD Digital Output Voltage to ...

  • Page 10

    AD7475/AD7495 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Table 5. Pin Descriptions Pin No. Mnemonic Function 1 (AD7475) REF IN Reference Input for the AD7475. An external reference must be applied to this input. The voltage range for the external reference is ...

  • Page 11

    TERMINOLOGY Integral Nonlinearity The maximum deviation from a straight line passing through the endpoints of the ADC transfer function. The endpoints of the transfer function are zero scale, a point ½ LSB below the first code transition, and full scale, ...

  • Page 12

    AD7475/AD7495 TYPICAL PERFORMANCE CURVES Figure 7 shows a typical FFT plot for the AD7475 MHz sample rate and a 100 kHz input frequency. –15 –35 –55 –75 –95 –115 0 50 100 150 200 250 300 FREQUENCY ...

  • Page 13

    THEORY OF OPERATION The AD7475/AD7495 are fast, micropower, 12-bit, single- supply analog-to-digital converters (ADCs). The parts can be operated from a 2 5.25 V supply. When operated from either supply supply, ...

  • Page 14

    AD7475/AD7495 TYPICAL CONNECTION DIAGRAM Figure 13 and Figure 15 show typical connection diagrams for the AD7475 and AD7495, respectively. In both setups the GND pin is connected to the analog ground plane of the system. In Figure 13, REF IN ...

  • Page 15

    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 16

    AD7475/AD7495 OPERATING MODES The AD7475/AD7495 operating mode is selected by controlling the logic state of the CS signal during a conversion. There are three possible modes of operation: normal mode, partial power- down mode, and full power-down mode. The point ...

  • Page 17

    To exit this operating mode and power up the AD7475/AD7495 again, a dummy conversion is performed. On the falling edge the device begins to power up and continues to power up as long held ...

  • Page 18

    AD7475/AD7495 Full power-down is entered in a way similar to partial power- down, except the timing sequence shown in Figure 20 must be executed twice. The conversion process must be interrupted in a similar fashion by bringing CS high anywhere ...

  • Page 19

    POWER VS. THROUGHPUT RATE By using the partial power-down mode on the AD7475/ AD7495 when not converting, the average power consumption of the ADC decreases at lower throughput rates. Figure 24 shows how, as the throughput rate is reduced, the ...

  • Page 20

    AD7475/AD7495 SERIAL INTERFACE Figure 26 shows the detailed timing diagram for serial inter- facing to the AD7475/AD7495. The serial clock provides the conversion clock and also controls the transfer of information from the AD7475/AD7495 during conversion. CS initiates the data ...

  • Page 21

    MICROPROCESSOR INTERFACING The serial interface on the AD7475/AD7495 allows the parts to be directly connected to a range of many different micro- processors. This section explains how to interface the AD7475/ AD7495 with some of the more common microcontroller and ...

  • Page 22

    AD7475/AD7495 The timer registers are loaded with a value that provides an interrupt at the required sample interval. When an interrupt is received, a value is transmitted with TFS/DT (ADC control word). The TFS is used to control the RFS, ...

  • Page 23

    OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890 6.20 (0.2440) 4.00 (0.1574) 5.80 (0.2284) 3.80 (0.1497 1.27 (0.0500) BSC 1.75 (0.0688) 1.35 (0.0532) 0.25 (0.0098) 0.10 (0.0040) 0.51 (0.0201) COPLANARITY 0.25 (0.0098) 0.31 (0.0122) SEATING 0.10 0.17 (0.0067) ...

  • Page 24

    ... AD7495BR-REEL7 −40°C to +85°C 3 AD7495BRZ −40°C to +85°C 3 AD7495BRZ-REEL −40°C to +85°C 3 AD7495BRZ-REEL7 −40°C to +85°C AD7495ARM −40°C to +85°C AD7495ARM-REEL −40°C to +85°C AD7495ARM-REEL7 −40°C to +85°C AD7495ARMZ 3 −40°C to +85°C ...