4-Channel, 1.5 MSPS, 10-Bit and 12-Bit
Parallel ADCs with a Sequencer
AD7933/AD7934
FEATURES
Throughput rate: 1.5 MSPS
Specified for V
DD
of 2.7 V to 5.25 V
Low power
6 mW maximum at 1.5 MSPS with 3 V supplies
13.5 mW maximum at 1.5 MSPS with 5 V supplies
4 analog input channels with a sequencer
Software configurable analog inputs
4-channel single-ended inputs
2-channel fully differential inputs
2-channel pseudo differential inputs
Accurate on-chip 2.5 V reference
±0.2% maximum @ 25°C, 25 ppm/°C maximum (AD7934)
70 dB SINAD at 50 kHz input frequency
No pipeline delays
High speed parallel interface—word/byte modes
Full shutdown mode: 2 μA maximum
28-lead TSSOP package
FUNCTIONAL BLOCK DIAGRAM
V
DD
V
REFIN/
2.5V
VREF
12-/10-BIT
SAR ADC
AND
CONTROL
CLKIN
CONVST
BUSY
AGND
AD7933/AD7934
V
REFOUT
V
IN
0
I/P
MUX
V
IN
3
T/H
SEQUENCER
PARALLEL INTERFACE/CONTROL REGISTER
V
DRIVE
DB0 DB11
CS RD WR W/B
DGND
Figure 1.
GENERAL DESCRIPTION
The AD7933/AD7934 are 10-bit and 12-bit, high speed, low
power, successive approximation (SAR) analog-to-digital
converters (ADCs). The parts operate from a single 2.7 V to
5.25 V power supply and feature throughput rates up to 1.5 MSPS.
The parts contain a low noise, wide bandwidth, differential track-
and-hold amplifier that handles input frequencies up to 50 MHz.
The AD7933/AD7934 feature four analog input channels with a
channel sequencer that allows a preprogrammed selection of
channels to be sequentially converted. These parts can accept
either single-ended, fully differential, or pseudo differential
analog inputs.
The conversion process and data acquisition are controlled
using standard control inputs that allow for easy interfacing to
microprocessors and DSPs. The input signal is sampled on the
falling edge of CONVST, and the conversion is also initiated at
this point.
The AD7933/AD7934 has an accurate on-chip 2.5 V reference
that is used as the reference source for the analog-to-digital
conversion. Alternatively, this pin can be overdriven to provide
an external reference.
These parts use advanced design techniques to achieve very low
power dissipation at high throughput rates. They also feature
flexible power management options. An on-chip control
register allows the user to set up different operating conditions,
including analog input range and configuration, output coding,
power management, and channel sequencing.
PRODUCT HIGHLIGHTS
1.
2.
3.
4.
5.
High throughput with low power consumption.
Four analog inputs with a channel sequencer.
Accurate on-chip 2.5 V reference.
Single-ended, pseudo differential or fully differential
analog inputs that are software selectable.
Single-supply operation with V
DRIVE
function.
The V
DRIVE
function allows the parallel interface to connect
directly to 3 V or 5 V processor systems independent of V
DD
.
No pipeline delay.
Accurate control of the sampling instant via a CONVST
input and once-off conversion control.
6.
7.
Table 1. Related Devices
Device
AD7938/AD7939
AD7938-6
AD7934-6
No. of Bits
12/10
12
12
No. of Channels
8
8
4
Speed
1.5 MSPS
625 kSPS
625 kSPS
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113 ©2005–2007 Analog Devices, Inc. All rights reserved.
03713-001
AD7933/AD7934
TABLE OF CONTENTS
Features .............................................................................................. 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Product Highlights ........................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
AD7933 Specifications................................................................. 3
AD7934 Specifications................................................................. 5
Timing Specifications .................................................................. 7
Absolute Maximum Ratings............................................................ 8
ESD Caution.................................................................................. 8
Pin Configuration and Function Descriptions............................. 9
Typical Performance Characteristics ........................................... 11
Terminology .................................................................................... 13
Control Register.............................................................................. 15
Sequencer Operation ................................................................. 16
Circuit Information ........................................................................ 17
Converter Operation.................................................................. 17
ADC Transfer Function............................................................. 17
Typical Connection Diagram ................................................... 18
Analog Input Structure.............................................................. 18
Analog Inputs ............................................................................. 19
Analog Input Selection .............................................................. 21
Reference ..................................................................................... 22
Parallel Interface......................................................................... 23
Power Modes of Operation ....................................................... 26
Power vs. Throughput Rate....................................................... 27
Microprocessor Interfacing....................................................... 27
Application Hints ........................................................................... 29
Grounding and Layout .............................................................. 29
Evaluating the AD7933/AD7934 Performance...................... 29
Outline Dimensions ....................................................................... 30
Ordering Guide .......................................................................... 30
REVISION HISTORY
2/07—Rev. A to Rev B
Changes to Timing Specifications .................................................. 7
Changes to Figure 13...................................................................... 12
12/05—Rev. 0 to Rev. A
Replaced Figures .................................................................Universal
Changes to General Description .................................................... 1
Changes to Product Highlights....................................................... 1
Added Table 1.................................................................................... 1
Changes to Specifications Section.................................................. 3
Changes to Table 5............................................................................ 9
Changes to Terminology Section.................................................. 13
Changes to Control Register Section ........................................... 15
Changes to Circuit Information Section ..................................... 17
Changes to Application Hints Section......................................... 29
1/05—Revision 0: Initial Version
Rev. B | Page 2 of 32
AD7933/AD7934
SPECIFICATIONS
AD7933 SPECIFICATIONS
V
DD
= V
DRIVE
= 2.7 V to 5.25 V, internal/external V
REF
= 2.5 V, unless otherwise noted. f
CLKIN
= 25.5 MHz, f
SAMPLE
= 1.5 MSPS; T
A
= T
MIN
to
T
MAX1
, unless otherwise noted.
Table 2.
Parameter
DYNAMIC PERFORMANCE
Signal-to-Noise + Distortion (SINAD)
2
Total Harmonic Distortion (THD)
2
Peak Harmonic or Spurious Noise (SFDR)
2
Intermodulation Distortion (IMD)
2
Second-Order Terms
Third-Order Terms
Channel-to-Channel Isolation
Aperture Delay
2
Aperture Jitter
2
Full Power Bandwidth
2
DC ACCURACY
Resolution
Integral Nonlinearity
2
Differential Nonlinearity
2
Single-Ended and Pseudo Differential
Input
Offset Error
2
Offset Error Match
2
Gain Error
2
Gain Error Match
2
Fully Differential Input
Positive Gain Error
2
Positive Gain Error Match
2
Zero-Code Error
2
Zero-Code Error Match
2
Negative Gain Error
2
Negative Gain Error Match
2
ANALOG INPUT
Single-Ended Input Range
Pseudo Differential Input Range
V
IN+
V
IN−
Fully Differential Input Range
3
V
IN+
and V
IN−
V
IN+
and V
IN−
DC Leakage Current
4
Input Capacitance
Value
1
61
60
−70
−72
−86
−90
−75
5
72
50
10
10
±0.5
±0.5
Unit
dB min
dB min
dB max
dB max
dB typ
dB typ
dB typ
ns typ
ps typ
MHz typ
MHz typ
Bits
LSB max
LSB max
Test Conditions/Comments
f
IN
= 50 kHz sine wave
Differential mode
Single-ended mode
fa = 30 kHz, fb = 50 kHz
f
IN
= 50 kHz, f
NOISE
= 300 kHz
@ 3 dB
@ 0.1 dB
Guaranteed no missed codes to 10 bits
Straight binary output coding
±2
±0.5
±1.5
±0.5
±1.5
±0.5
±2
±0.5
±1.5
±0.5
0 to V
REF
0 to 2 × V
REF
0 to V
REF
0 to 2 × V
REF
−0.3 to +0.7
−0.3 to +1.8
V
CM
± V
REF
/2
V
CM
± V
REF
±1
45
10
LSB max
LSB max
LSB max
LSB max
Twos complement output coding
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
V
V
V
V
V typ
V typ
V
V
μA max
pF typ
pF typ
RANGE bit = 0
RANGE bit = 1
RANGE bit = 0
RANGE bit = 1
V
DD
= 3 V
V
DD
= 5 V
V
CM
= V
REF
/2, RANGE bit = 0
V
CM
= V
REF
, RANGE bit = 1
When in track
When in hold
Rev. B | Page 3 of 32
AD7933/AD7934
Parameter
REFERENCE INPUT/OUTPUT
V
REF
Input Voltage
5
DC Leakage Current
4
V
REFOUT
Output Voltage
V
REFOUT
Temperature Coefficient
V
REF
Noise
V
REF
Output Impedance
V
REF
Input Capacitance
LOGIC INPUTS
Input High Voltage, V
INH
Input Low Voltage, V
INL
Input Current, I
IN
Input Capacitance, C
IN4
LOGIC OUTPUTS
Output High Voltage, V
OH
Output Low Voltage, V
OL
Floating-State Leakage Current
Floating-State Output Capacitance
4
Output Coding
CONVERSION RATE
Conversion Time
Track-and-Hold Acquisition Time
Throughput Rate
POWER REQUIREMENTS
V
DD
V
DRIVE
I
DD 6
Normal Mode (Static)
Normal Mode (Operational)
Autostandby Mode
Full/Autoshutdown Mode (Static)
Power Dissipation
Normal Mode (Operational)
Autostandby Mode (Static)
Full/Autoshutdown Mode
Value
1
2.5
±1
2.5
25
5
10
130
10
15
25
2.4
0.8
±5
10
2.4
0.4
±3
10
Straight (natural) binary
Twos complement
t
2
+ 13 t
CLK
125
80
1.5
2.7/5.25
2.7/5.25
0.8
2.7
2.0
0.3
160
2
13.5
6
800
480
10
6
Unit
V
μA max
V
ppm/°C max
ppm/°C typ
μV typ
μV typ
Ω typ
pF typ
pF typ
V min
V max
μA max
pF max
V min
V max
μA max
pF max
Test Conditions/Comments
±1% specified performance
±0.2% max @ 25°C
0.1 Hz to 10 Hz bandwidth
0.1 Hz to 1 MHz bandwidth
When in track
When in hold
Typically 10 nA, V
IN
= 0 V or V
DRIVE
I
SOURCE
= 200 μA
I
SINK
= 200 μA
CODING bit = 0
CODING bit = 1
ns
ns max
ns typ
MSPS max
V min/max
V min/max
mA typ
mA max
mA max
mA typ
μA typ
μA max
mW max
mW max
μW typ
μW typ
μW max
μW max
Digital inputs = 0 V or V
DRIVE
V
DD
= 2.7 V to 5.25 V, SCLK on or off
V
DD
= 4.75 V to 5.25 V
V
DD
= 2.7 V to 3.6 V
F
SAMPLE
= 100 kSPS, V
DD
= 5 V
Static
SCLK on or off
V
DD
= 5 V
V
DD
= 3 V
V
DD
= 5 V
V
DD
= 3 V
V
DD
= 5 V
V
DD
= 3 V
Full-scale step input
Sine wave input
1
2
Temperature range is −40°C to +85°C.
See Terminology section.
3
V
CM
is the common-mode voltage. For full common-mode range, see Figure 25 and Figure 26. V
IN+
and V
IN−
must always remain within GND/V
DD
.
4
Sample tested during initial release to ensure compliance.
5
This device is operational with an external reference in the range of 0.1 V to V
DD
. See the Reference section for more information.
6
Measured with a midscale dc analog input.
Rev. B | Page 4 of 32
AD7933/AD7934
AD7934 SPECIFICATIONS
V
DD
= V
DRIVE
= 2.7 V to 5.25 V, internal/external V
REF
= 2.5 V, unless otherwise noted. f
CLKIN
= 25.5 MHz, f
SAMPLE
= 1.5 MSPS;
T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Table 3.
Parameter
DYNAMIC PERFORMANCE
Signal-to-Noise + Distortion (SINAD)
2
Signal-to-Noise Ratio (SNR)
2
Total Harmonic Distortion (THD)
2
Peak Harmonic or Spurious Noise (SFDR)
2
Intermodulation Distortion (IMD)
2
Second-Order Terms
Third-Order Terms
Channel-to-Channel Isolation
Aperture Delay
2
Aperture Jitter
2
Full Power Bandwidth
2
DC ACCURACY
Resolution
Integral Nonlinearity
2
Differential Nonlinearity
2
Differential Mode
Single-Ended Mode
Single-Ended and Pseudo Differential Input
Offset Error
2
Offset Error Match
2
Gain Error
2
Gain Error Match
2
Fully Differential Input
Positive Gain Error
2
Positive Gain Error Match
2
Zero-Code Error
2
Zero-Code Error Match
2
Negative Gain Error
2
Negative Gain Error Match
2
ANALOG INPUT
Single-Ended Input Range
Pseudo Differential Input Range
V
IN+
V
IN−
Fully Differential Input Range
3
V
IN+
and V
IN−
V
IN+
and V
IN−
DC Leakage Current
4
Input Capacitance
Value
1
70
68
71
69
−73
−70
−73
−86
−90
−85
5
72
50
10
12
±1
±1.5
±0.95
−0.95/+1.5
±6
±1
±3
±1
±3
±1
±6
±1
±3
±1
0 to V
REF
0 to 2 × V
REF
0 to V
REF
0 to 2 × V
REF
−0.3 to +0.7
−0.3 to +1.8
V
CM
± V
REF
/2
V
CM
± V
REF
±1
45
10
Rev. B | Page 5 of 32
Unit
dB min
dB min
dB min
dB min
dB max
dB max
dB max
dB typ
dB typ
dB typ
ns typ
ps typ
MHz typ
MHz typ
Bits
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
V
V
V
V
V typ
V typ
V
V
μA max
pF typ
pF typ
Test Conditions/Comments
f
IN
= 50 kHz sine wave
Differential mode
Single-ended mode
Differential mode
Single-ended mode
−85 dB typ, differential mode
−80 dB typ, single-ended mode
−82 dB typ
fa = 30 kHz, fb = 50 kHz
f
IN
= 50 kHz, f
NOISE
= 300 kHz
@ 3 dB
@ 0.1 dB
Differential mode
Single-ended mode
Guaranteed no missed codes to 12 bits
Guaranteed no missed codes to 12 bits
Straight binary output coding
Twos complement output coding
RANGE bit = 0
RANGE bit = 1
RANGE bit = 0
RANGE bit = 1
V
DD
= 3 V
V
DD
= 5 V
V
CM
= V
REF
/2, RANGE bit = 0
V
CM
= V
REF
, RANGE bit = 1
When in track
When in hold
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