AD7887ARM-REEL Analog Devices Inc, AD7887ARM-REEL Datasheet

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AD7887ARM-REEL

Manufacturer Part Number
AD7887ARM-REEL
Description
Manufacturer
Analog Devices Inc
Datasheet

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AD7887ARM-REEL7
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AD
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2 518
FEATURES
Specified for V
Flexible power/throughput rate management
Shutdown mode: 1 μA max
One or two single-ended inputs
Serial interface: SPI®/QSPI™/MICROWIRE™/DSP compatible
8-lead narrow SOIC and MSOP packages
APPLICATIONS
Battery-powered systems (personal digital assistants,
Instrumentation and control systems
High speed modems
GENERAL DESCRIPTION
The AD7887 is a high speed, low power, 12-bit analog-to-digital
converter (ADC) that operates from a single 2.7 V to 5.25 V
power supply. The AD7887 is capable of 125 kSPS throughput
rate. The input track-and-hold acquires a signal in 500 ns and
features a single-ended sampling scheme. The output coding for
the AD7887 is straight binary, and the part is capable of
converting full power signals of up to 2.5 MHz.
The AD7887 can be configured for either dual- or single-channel
operation via the on-chip control register. There is a default
single-channel mode that allows the AD7887 to be operated as a
read-only ADC. In single-channel operation, there is one
analog input (AIN0) and the AIN1/V
function. This V
internal 2.5 V reference, or the V
external reference to provide the reference voltage for the part.
This external reference voltage has a range of 2.5 V to V
analog input range on AIN0 is 0 to V
In dual-channel operation, the AIN1/V
function, providing a second analog input channel. In this case,
the reference voltage for the part is provided via the V
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.
medical instruments, mobile communications)
DD
REF
of 2.7 V to 5.25 V
pin allows the user access to the part’s
REF
pin can be overdriven by an
REF
REF
REF
.
pin assumes its V
pin assumes its AIN1
2.7 V to 5.25 V, Micropower, 2-Channel,
DD
DD
pin. As
125 kSPS, 12-Bit ADC in 8-Lead MSOP
REF
. The
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
a result, the input voltage range on both the AIN0 and AIN1
inputs is 0 to V
CMOS construction ensures low power dissipation of typically
2 mW for normal operation and 3 μW in power-down mode.
The part is available in an 8-lead, 0.15-inch-wide narrow body
SOIC and an 8-lead MSOP package.
PRODUCT HIGHLIGHTS
1.
2.
3.
4.
5.
6.
AIN1/
V
AIN0
Smallest 12-bit dual-/single-channel ADC; 8-lead MSOP
package.
Lowest power 12-bit dual-/single-channel ADC.
Flexible power management options, including automatic
power-down after conversion.
Read-only ADC capability.
Analog input range from 0 V to V
Versatile serial input/output port (SPI/QSPI/MICROWIRE/
DSP compatible).
V
REF
DD
FUNCTIONAL BLOCK DIAGRAM
SOFTWARE
AIN1/V
CONTROL
LATCH
DD
.
REF
DIN
©2006 Analog Devices, Inc. All rights reserved.
MUX
REDISTRIBUTION
I/P
CONTROL LOGIC
SAR + ADC
CS
Figure 1.
CHARGE
BUF
SPORT
DAC
2.5V
REF
DOUT
T/H
REF
SCLK
.
AD7887
COMP
AD7887
www.analog.com
GND

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AD7887ARM-REEL Summary of contents

Page 1

... 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. ...

Page 2

AD7887 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 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 Pin ...

Page 3

SPECIFICATIONS 2.5 V, external/internal reference unless otherwise noted REF Table 1. Parameter DYNAMIC PERFORMANCE 2, 3 Signal to Noise + Distortion Ratio (SNR) 2 Total Harmonic Distortion (THD) 2 ...

Page 4

AD7887 Parameter CONVERSION RATE Throughput Time 2 Track/Hold Acquisition Time Conversion Time POWER REQUIREMENTS Normal Mode (Mode 2) Static Operational (f = 125 kSPS) SAMPLE Using Standby Mode (Mode 4) Using Shutdown Mode (Modes 1, ...

Page 5

TIMING SPECIFICATIONS Table 2. Limit at T (A, B Versions) Parameter 4. 5. SCLK t 14.5 × t CONVERT SCLK t 1.5 × t ACQ SCLK ...

Page 6

AD7887 ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 3. Parameter V to AGND DD Analog Input Voltage to AGND Digital Input Voltage to AGND Digital Output Voltage to AGND REF /REF to AGND IN OUT Input ...

Page 7

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS CS 1 AD7887 GND 3 TOP VIEW (Not to Scale) AIN1/V 4 REF Figure 3. SOIC_N Pin Configuration Table 4. Pin Function Descriptions Pin No. Mnemonic Description 1 CS Chip Select. Active ...

Page 8

AD7887 TYPICAL PERFORMANCE CHARACTERISTICS 0 –10 –30 –50 –70 –90 –110 Figure 5. Dynamic Performance 73 EXT REFERENCE 72.5 72.0 71.5 71.0 0.15 10.89 21.14 INPUT FREQUENCY (kHz) Figure 6. SNR vs. Input Frequency 4096 POINT FFT SAMPLING ...

Page 9

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 ½ LSB below the first code transition, ...

Page 10

AD7887 CONTROL REGISTER The control register on the AD7887 is an 8-bit, write-only register. Data is loaded from the DIN pin of the AD7887 on the rising edge of SCLK. The data is transferred on the DIN line at the ...

Page 11

THEORY OF OPERATION CIRCUIT INFORMATION The AD7887 is a fast, low power, 12-bit, single-supply, single- channel/dual-channel ADC. The part can be operated from (2 3.6 V) supply or from (4. ...

Page 12

AD7887 ANALOG INPUT Figure 12 shows an equivalent circuit of the analog input structure of the AD7887. The two diodes, D1 and D2, provide ESD protection for the analog inputs. Care must be taken to ensure that the analog input ...

Page 13

POWER-DOWN OPTIONS The AD7887 provides flexible power management to allow the user to achieve the best power performance for a given throughput rate. The power management options are selected by programming the power management bits (that is, PM1 and PM0) ...

Page 14

AD7887 second conversion can put the part back into Mode 1, and the part goes into power-down mode when CS returns high. Mode 2 (PM1 = 0, PM0 = 1) In this mode of operation, the AD7887 remains fully powered ...

Page 15

THE PART POWERS FALLING EDGE AS PM1 AND PM0 = SCLK FOUR LEADING ZEROS + CONVERSION RESULT DOUT DIN DATA IN CONTROL REGISTER DATA IS LOADED ON THE FIRST EIGHT CLOCKS. PM1 AND PM0 ...

Page 16

AD7887 THE PART ENTERS SHUTDOWN AT THE END OF CONVERSION AS PM1 = 1 AND PM0 = SCLK FOUR LEADING ZEROS + CONVERSION RESULT DOUT DATA IN DIN CONTROL REGISTER DATA IS LOADED ON THE FIRST EIGHT ...

Page 17

SERIAL INTERFACE Figure 21 shows the detailed timing diagrams for serial interfacing to the AD7887. The serial clock provides the conversion clock and also controls the transfer of information to and from the AD7887 during conversion. CS initiates the data ...

Page 18

AD7887 MICROPROCESSOR INTERFACING The serial interface on the AD7887 allows the part to be directly connected to a range of many different microprocessors. This section explains how to interface the AD7887 with some of the more common microcontroller and DSP ...

Page 19

AD7887 to MC68HC11 The serial peripheral interface (SPI) on the MC68HC11 is configured for master mode (MSTR = 1) when the clock polarity bit (CPOL and the clock phase bit (CPHA The SPI is configured by ...

Page 20

... PC via the EVAL-CONTROL BOARD. The EVAL-CONTROL BOARD can be used in conjunction with the AD7887 evaluation board, as well as many other Analog Devices, Inc., evaluation boards ending in the CB designator, to demonstrate/evaluate the ac and dc performance of the AD7887. ...

Page 21

... Dimensions shown in millimeters and (inches) ORDERING GUIDE Model Linearity Error (LSB) AD7887AR ±2 AD7887AR-REEL ±2 AD7887AR-REEL7 ±2 AD7887ARZ 2 ±2 2 AD7887ARZ-REEL ±2 AD7887ARZ-REEL7 2 ±2 AD7887ARM ±2 AD7887ARM-REEL ±2 AD7887ARM-REEL7 ±2 2 AD7887ARMZ ±2 2 AD7887ARMZ-REEL ±2 2 AD7887ARMZ-REEL7 ±2 AD7887BR ±1 AD7887BR-REEL ±1 AD7887BR-REEL7 ±1 2 AD7887BRZ ±1 AD7887BRZ-REEL 2 ±1 ...

Page 22

AD7887 NOTES Rev Page ...

Page 23

NOTES Rev Page AD7887 ...

Page 24

... AD7887 NOTES ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C06191-0-9/06(C) Rev Page ...

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