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Data Sheet
FEATURES
Fast throughput rate: 1 MSPS
Specified for AV
DD
of 2.7 V to 5.25 V
Low power:
6 mW maximum at 1 MSPS with 3 V supplies
13.5 mW maximum at 1 MSPS with 5 V supplies
4 single-ended inputs with sequencer
Wide input bandwidth
AD7924, 70 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
Shutdown mode: 0.5 µA maximum
16-lead TSSOP package
Qualified for automotive applications
4-Channel, 1 MSPS, 8-/10-/12-Bit ADCs
with Sequencer in 16-Lead TSSOP
AD7904/AD7914/AD7924
FUNCTIONAL BLOCK DIAGRAM
AV
DD
REF
IN
V
IN
0
T/H
V
IN
1
I/P
MUX
V
IN
2
8-/10-/12-BIT
SUCCESSIVE
APPROXIMATION
ADC
V
IN
3
SCLK
DOUT
SEQUENCER
CONTROL LOGIC
DIN
CS
AD7904/AD7914/AD7924
03087-001
V
DRIVE
AGND
Figure 1.
GENERAL DESCRIPTION
The AD7904/AD7914/AD7924 are, respectively, 8-bit, 10-bit, and
12-bit, high speed, low power, 4-channel successive approxi-
mation ADCs. The parts operate from a single 2.7 V to 5.25 V
power supply and feature throughput rates up to 1 MSPS. The
parts contain a low noise, wide bandwidth track-and-hold
amplifier that can handle input frequencies in excess of 8 MHz.
The conversion process and data acquisition are controlled using
CS and the serial clock signal, allowing the device to easily inter-
face with microprocessors or DSPs. The input signal is sampled
on the falling edge of CS and conversion is initiated at this
point. There are no pipeline delays associated with the part.
The AD7904/AD7914/AD7924 use advanced design techniques
to achieve very low power dissipation at maximum throughput
rates. At maximum throughput rates, the AD7904/AD7914/
AD7924 consume 2 mA maximum with 3 V supplies; with 5 V
supplies, the current consumption is 2.7 mA maximum.
Through the configuration of the control register, the analog
input range for the part can be selected as 0 V to REF
IN
or 0 V to
2 × REF
IN
, with either straight binary or twos complement output
coding. The AD7904/AD7914/AD7924 each feature four single-
ended analog inputs with a channel sequencer to allow a pre-
programmed selection of channels to be converted sequentially.
The conversion time for the AD7904/AD7914/AD7924 is
determined by the SCLK frequency, which is also used as the
master clock to control the conversion.
Rev. C
Document Feedback
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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.
PRODUCT HIGHLIGHTS
1.
High Throughput with Low Power Consumption.
The AD7904/AD7914/AD7924 offer throughput rates
up to 1 MSPS. At the maximum throughput rate with 3 V
supplies, the AD7904/AD7914/AD7924 dissipate only
6 mW of power maximum.
Four Single-Ended Inputs with Channel Sequencer.
A consecutive sequence of channels can be selected,
through which the ADC will cycle and convert on.
Single-Supply Operation with V
DRIVE
Function.
The AD7904/AD7914/AD7924 operate from a single 2.7 V
to 5.25 V supply. The V
DRIVE
function allows the serial inter-
face to connect directly to 3 V or 5 V processor systems,
independent of V
DD
.
Flexible Power/Serial Clock Speed Management.
The conversion rate is determined by the serial clock,
allowing the conversion time to be reduced by increasing
the serial clock speed. The parts also feature two shutdown
modes to maximize power efficiency at lower throughput
rates. Current consumption is 0.5 µA maximum when in
full shutdown.
No Pipeline Delay.
The parts feature a standard successive approximation
ADC with accurate control of the sampling instant via
the CS input and once-off conversion control.
2.
3.
4.
5.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 ©2002–2013 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
AD7904/AD7914/AD7924
TABLE OF CONTENTS
Features .............................................................................................. 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Product Highlights ........................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
AD7904 Specifications ................................................................. 3
AD7914 Specifications ................................................................. 5
AD7924 Specifications ................................................................. 7
Timing Specifications .................................................................. 9
Absolute Maximum Ratings .......................................................... 10
ESD Caution ................................................................................ 10
Pin Configuration and Function Descriptions ........................... 11
Typical Performance Characteristics ........................................... 12
Terminology .................................................................................... 14
Control Register .............................................................................. 15
Sequencer Operation ................................................................. 16
Data Sheet
Circuit Information ........................................................................ 18
Converter Operation.................................................................. 18
ADC Transfer Function ............................................................. 19
Typical Connection Diagram ................................................... 20
Modes of Operation ....................................................................... 22
Normal Mode (PM1 = PM0 = 1) ............................................. 22
Full Shutdown Mode (PM1 = 1, PM0 = 0) ............................. 22
Auto Shutdown Mode (PM1 = 0, PM0 = 1) ........................... 22
Powering Up the AD7904/AD7914/AD7924 ......................... 23
Power vs. Throughput Rate ........................................................... 25
Serial Interface ............................................................................ 25
Applications Information .............................................................. 27
Microprocessor Interfacing ....................................................... 27
Grounding and Layout .............................................................. 28
Outline Dimensions ....................................................................... 29
Ordering Guide .......................................................................... 29
Automotive Products ................................................................. 29
REVISION HISTORY
6/13—Rev. B to Rev. C
Deleted Evaluating AD7904/AD7914/AD7924 Performance
Section .............................................................................................. 29
Changes to Ordering Guide .......................................................... 29
7/11—Rev. A to Rev. B
Changes to Features Section............................................................ 1
Changes to Signal to (Noise + Distortion) (SINAD) Parameter
and Signal-to-Noise Ratio (SNR) Parameter in Table 1 .............. 3
Changes to Signal to (Noise + Distortion) (SINAD) Parameter
and Signal-to-Noise Ratio (SNR) Parameter in Table 2 .............. 5
Changes to Signal to (Noise + Distortion) (SINAD) Parameter
and Signal-to-Noise Ratio (SNR) Parameter in Table 3 .............. 7
Changes to Table 5 .......................................................................... 10
Changes to Ordering Guide .......................................................... 30
Added Automotive Products Section........................................... 30
2/09—Rev. 0 to Rev. A
Updated Format .................................................................. Universal
Moved Figure 2 ..................................................................................9
Change to Table 5 ........................................................................... 10
Changes to Typical Performance Characteristics Section ........ 12
Moved Terminology Section ......................................................... 14
Updated Outline Dimensions ....................................................... 30
Changes to Ordering Guide .......................................................... 30
11/02—Revision 0: Initial Version
Rev. C | Page 2 of 32
Data Sheet
SPECIFICATIONS
AD7904 SPECIFICATIONS
AD7904/AD7914/AD7924
AV
DD
= V
DRIVE
= 2.7 V to 5.25 V, REF
IN
= 2.5 V, f
SCLK
= 20 MHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Table 1.
Parameter
DYNAMIC PERFORMANCE
Signal to (Noise + Distortion) (SINAD)
2
Signal-to-Noise Ratio (SNR)
Total Harmonic Distortion (THD)
2
Peak Harmonic or Spurious Noise (SFDR)
Intermodulation Distortion (IMD)
Second-Order Terms
Third-Order Terms
Aperture Delay
Aperture Jitter
Channel-to-Channel Isolation
2
Full Power Bandwidth
DC ACCURACY
Resolution
Integral Nonlinearity (INL)
2
Differential Nonlinearity (DNL)
2
0 V to REF
IN
Input Range
Offset Error
2
Offset Error Match
2
Gain Error
2
Gain Error Match
2
0 V to 2 × REF
IN
Input Range
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
Input Voltage Range
DC Leakage Current
Input Capacitance
REFERENCE INPUT
REF
IN
Input Voltage
DC Leakage Current
REF
IN
Input Impedance
LOGIC INPUTS
Input High Voltage, V
INH
Input Low Voltage, V
INL
Input Current, I
IN
Input Capacitance, C
IN 3
B Version
1
49
48.5
49
48.5
−66
−64
−90
−90
10
50
−85
8.2
1.6
8
±0.2
±0.2
±0.5
±0.05
±0.2
±0.05
Unit
dB min
dB min
dB min
dB min
dB max
dB max
dB typ
dB typ
ns typ
ps typ
dB typ
MHz typ
MHz typ
Bits
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
−REF
IN
to +REF
IN
biased about REF
IN
with twos
complement output coding
±0.2
±0.05
±0.5
±0.1
±0.2
±0.05
0 to REF
IN
0 to 2 × REF
IN
±1
20
2.5
±1
36
0.7 × V
DRIVE
0.3 × V
DRIVE
±1
10
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
V
V
μA max
pF typ
V
μA max
kΩ typ
V min
V max
μA max
pF max
Rev. C | Page 3 of 32
Test Conditions/Comments
f
IN
= 50 kHz sine wave, f
SCLK
= 20 MHz
B models
W models
B models
W models
fa = 40.1 kHz, fb = 41.5 kHz
f
IN
= 400 kHz
@ 3 dB
@ 0.1 dB
Guaranteed no missed codes to 8 bits
Straight binary output coding
RANGE bit set to 1
RANGE bit set to 0, AV
DD
/V
DRIVE
= 4.75 V to 5.25 V
±1% specified performance
f
SAMPLE
= 1 MSPS
Typically 10 nA, V
IN
= 0 V or V
DRIVE
AD7904/AD7914/AD7924
Parameter
LOGIC OUTPUTS
Output High Voltage, V
OH
Output Low Voltage, V
OL
Floating-State Leakage Current
Floating-State Output Capacitance
3
Output Coding
CONVERSION RATE
Conversion Time
Track-and-Hold Acquisition Time
2
Throughput Rate
POWER REQUIREMENTS
V
DD
V
DRIVE
I
DD 4
Normal Mode (Static)
Normal Mode (Operational)
Auto Shutdown Mode
Full Shutdown Mode
Power Dissipation
4
Normal Mode (Operational)
Auto Shutdown Mode (Static)
Full Shutdown Mode
Temperature range for B versions: −40°C to +85°C.
See the Terminology section.
3
Sample tested @ 25°C to ensure compliance.
4
See the Power vs. Throughput Rate section.
1
2
Data Sheet
B Version
1
Unit
Test Conditions/Comments
I
SOURCE
= 200 μA, AV
DD
= 2.7 V to 5.25 V
I
SINK
= 200 μA
V
DRIVE
− 0.2
V min
0.4
V max
±1
μA max
10
pF max
Straight (natural) binary
Twos complement
800
300
300
1
2.7/5.25
2.7/5.25
600
2.7
2
960
0.5
0.5
13.5
6
2.5
1.5
2.5
1.5
ns max
ns max
ns max
MSPS max
V min/V max
V min/V max
μA typ
mA max
mA max
μA typ
μA max
μA max
mW max
mW max
μW max
μW max
μW max
μW max
Digital inputs = 0 V or V
DRIVE
AV
DD
= 2.7 V to 5.25 V, SCLK on or off
AV
DD
= 4.75 V to 5.25 V, f
SCLK
= 20 MHz
AV
DD
= 2.7 V to 3.6 V, f
SCLK
= 20 MHz
f
SAMPLE
= 250 kSPS
Static
SCLK on or off (20 nA typ)
AV
DD
= 5 V, f
SCLK
= 20 MHz
AV
DD
= 3 V, f
SCLK
= 20 MHz
AV
DD
= 5 V
AV
DD
= 3 V
AV
DD
= 5 V
AV
DD
= 3 V
CODING bit set to 1
CODING bit set to 0
16 SCLK cycles with SCLK at 20 MHz
Sine wave input
Full-scale step input
See the Serial Interface section
Rev. C | Page 4 of 32
