Data Sheet
FEATURES
16-Bit, 2 MSPS/1 MSPS/500 kSPS,
Precision, Pseudo Differential, SAR ADCs
AD4000/AD4004/AD4008
and AD4008 offer 2 MSPS, 1 MSPS, and 500 kSPS throughputs,
respectively. They incorporate ease of use features that reduce
signal chain power consumption, reduce signal chain complexity,
and enable higher channel density. The high-Z mode, coupled
with a long acquisition phase, eliminates the need for a dedicated
high power, high speed ADC driver, thus broadening the range
of low power precision amplifiers that can drive these ADCs
directly while still achieving optimum performance. The input
span compression feature enables the ADC driver amplifier and
the ADC to operate off of common supply rails without the need
for a negative supply while preserving the full ADC code range.
The low serial peripheral interface (SPI) clock rate requirement
reduces the digital input/output power consumption, broadens
processor options, and simplifies the task of sending data across
digital isolation.
Operating from a 1.8 V supply, the AD4000/AD4004/AD4008
sample an analog input (IN+) from 0 V to VREF with respect to
a ground sense (IN−) with VREF ranging from 2.4 V to 5.1 V.
The AD4000 consumes only 14 mW at 2 MSPS with a minimum
SCK rate of 70 MHz in turbo mode, the AD4004 consumes only
7 mW at 1 MSPS, and the AD4008 consumes only 3.5 mW at
500 kSPS. The AD4000/AD4004/AD4008 all achieve ±1.0 LSB
integral nonlinearity error (INL) maximum, guaranteed no
missing codes at 16 bits, and 93 dB signal-to-noise ratio (SNR)
for 1 kHz inputs. The reference voltage is applied externally and
can be set independently of the supply voltage.
The SPI-compatible versatile serial interface features seven
different modes including the ability, using the SDI input, to
daisy-chain several ADCs on a single 3-wire bus, and provides
an optional busy indicator. The AD4000/AD4004/AD4008 are
compatible with 1.8 V, 2.5 V, 3 V, and 5 V logic, using the
separate VIO supply.
The AD4000/AD4004 are available in a 10-lead MSOP and a
10-lead LFCSP, and the AD4008 is available in a 10-lead LFCSP,
with operation specified from −40°C to +125°C. The devices are
pin compatible with the 18-bit, 2 MSPS
AD4003
(see Table 8).
1.8V
VDD
VIO
TURBO
MODE
Throughput: 2 MSPS/1 MSPS/500 kSPS options
INL: ±1.0 LSB maximum
Guaranteed 16-bit, no missing codes
Low power
9.75 mW at 2 MSPS, 4.9 mW at 1 MSPS, 2.5 mW at 500 kSPS
(VDD only)
70 µW at 10 kSPS, 14 mW at 2 MSPS (total)
SNR: 93 dB typical at 1 kHz, V
REF
= 5 V; 90 dB typical at 100 kHz
THD: −115 dB typical at 1 kHz, V
REF
= 5 V; −95 dB typical at 100 kHz
Ease of use features reduce system power and complexity
Input overvoltage clamp circuit
Reduced nonlinear input charge kickback
High-Z mode
Long acquisition phase
Input span compression
Fast conversion time allows low SPI clock rates
SPI-programmable modes, read/write capability, status word
Pseudo differential (single-ended) analog input range
0 V to V
REF
with V
REF
from 2.4 V to 5.1 V
Single 1.8 V supply operation with 1.71 V to 5.5 V logic interface
SAR architecture: no latency/pipeline delay, valid first conversion
First conversion accurate
Guaranteed operation: −40°C to +125°C
SPI-/QSPI-/MICROWIRE-/DSP-compatible serial interface
Ability to daisy-chain multiple ADCs and busy indicator
10-lead packages: 3 mm × 3 mm LFCSP, 3 mm × 4.90 mm MSOP
APPLICATIONS
Automatic test equipment
Machine automation
Medical equipment
Battery-powered equipment
Precision data acquisition systems
GENERAL DESCRIPTION
The AD4000/AD4004/AD4008 are low noise, low power, high
speed, 16-bit, precision successive approximation register (SAR)
analog-to-digital converters (ADCs). The AD4000, AD4004,
2.4V TO 5.1V
10µF
V
REF
V
REF
/2
0
HIGH-Z
MODE
REF
FUNCTIONAL BLOCK DIAGRAM
IN+
IN–
AD4000/
AD4004/
AD4008
16-BIT
SAR ADC
1.8V TO 5V
3-WIRE OR 4-WIRE
SPI INTERFACE
(DAISY CHAIN, CS)
14956-001
SDI
SCK
SDO
CNV
SERIAL
INTERFACE
STATUS
BITS
SPAN
CLAMP
COMPRESSION
GND
Figure 1.
Rev. C
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AD4000/AD4004/AD4008
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 3
Specifications..................................................................................... 4
Timing Specifications .................................................................. 7
Absolute Maximum Ratings............................................................ 9
Thermal Resistance ...................................................................... 9
ESD Caution .................................................................................. 9
Pin Configurations and Function Descriptions ......................... 10
Typical Performance Characteristics ........................................... 11
Terminology .................................................................................... 16
Theory of Operation ...................................................................... 17
Circuit Information .................................................................... 17
Converter Operation .................................................................. 18
Transfer Functions...................................................................... 18
Applications Information .............................................................. 19
Typical Application Diagrams .................................................. 19
Data Sheet
Analog Inputs ............................................................................. 20
Driver Amplifier Choice ........................................................... 21
Ease of Drive Features ............................................................... 22
Voltage Reference Input ............................................................ 23
Power Supply............................................................................... 24
Digital Interface .......................................................................... 24
Register Read/Write Functionality........................................... 25
Status Word ................................................................................. 27
CS Mode, 3-Wire Turbo Mode ................................................. 28
CS Mode, 3-Wire Without Busy Indicator ............................. 29
CS Mode, 3-Wire with Busy Indicator .................................... 30
CS Mode, 4-Wire Turbo Mode ................................................. 31
CS Mode, 4-Wire Without Busy Indicator ............................. 32
CS Mode, 4-Wire with Busy Indicator .................................... 33
Daisy-Chain Mode ..................................................................... 34
Layout Guidelines....................................................................... 35
Evaluating the AD4000/AD4004/AD4008 Performance .......... 35
Outline Dimensions ....................................................................... 36
Ordering Guide .......................................................................... 36
Rev. C | Page 2 of 36
Data Sheet
REVISION HISTORY
10/2017—Rev. B to Rev. C
Changes to Features Section ............................................................ 1
Added Multiplexed Applications Section ....................................21
Changes to Ordering Guide ...........................................................36
9/2017—Rev. A to Rev. B
Added AD4008 ................................................................... Universal
Changes to Title, Features Section, General Description Section,
and Figure 1........................................................................................ 1
Changes to Table 1 ............................................................................ 4
Changes to Timing Specifications Section and Table 2................ 7
Changes to Table 4 ............................................................................ 8
Changes to Table 5 ............................................................................ 9
Changes to Typical Performance Characteristics Section Layout .. 11
Changes to Figure 19 ............................................................................... 13
Added Figure 25; Renumbered Sequentially ...............................14
Changes to Figure 28 ......................................................................14
Change to Zero Error Definition, Terminology Section............16
Changes to Circuit Information Section and Table 8 .................17
Changes to Converter Operation Section and Note 1 and
Note 2, Table 9 .................................................................................18
Changes to High Frequency Input Signals Section, Figure 36
Caption, and Figure 37 Caption ....................................................21
Added Figure 38 ..............................................................................21
Changes to Input Span Compression Section, High-Z Mode
Section, Figure 40, and Figure 41 Caption ...................................22
Changes to Figure 42 Caption, Figure 43 Caption, Power Supply
Section, and Figure 44 Caption .....................................................23
Changes to Figure 45, Digital Interface Section, and Table 11 ........ 24
Changes to Register Read/Write Functionality Section and
Figure 46 Caption ............................................................................25
Changes to CS Mode, 3-Wire Turbo Mode Section ...................28
Changes to CS Mode, 3-Wire with Busy Indicator Section .......30
Changes to CS Mode, 4-Wire Turbo Mode Section ...................31
Changes to CS Mode, 4-Wire with Busy Indicator Section .......33
Changes to Daisy-Chain Mode Section .......................................34
Changed Evaluating the AD4000/AD4004 Performance Section
to Evaluating the AD4000/AD4004/AD4008 Performance
Section ..............................................................................................35
Changes to Evaluating the AD4000/AD4004/AD4008
Performance Section .......................................................................35
Changes to Ordering Guide ...........................................................36
AD4000/AD4004/AD4008
4/2017—Rev. 0 to Rev. A
Added AD4004 ................................................................... Universal
Changes to Title, Features Section, General Description Section,
and Figure 1 ....................................................................................... 1
Changes to Table 1 ............................................................................ 3
Changes to Table 2 ............................................................................ 6
Changes to Table 4 ............................................................................ 7
Changes to Table 7 ............................................................................ 9
Changes to Figure 19 and Figure 21 ............................................. 12
Changes to Figure 24 ...................................................................... 13
Added Figure 25; Renumbered Sequentially ............................... 13
Moved Terminology Section ......................................................... 15
Changes to Circuit Information Section and Table 8 ................. 16
Changes to Figure 33 ...................................................................... 18
Changes to RC Filters Section ....................................................... 19
Changes to High Frequency Input Signals Section .................... 20
Changes to High-Z Mode Section, Figure 38, and Figure 39 .... 21
Changes to Long Acquisition Phase Section and Figure 43 ...... 22
Changes to Digital Interface Section and Register Read/Write
Functionality Section ...................................................................... 23
Changes to Figure 45 ...................................................................... 24
Changes to CS Mode, 3-Wire Turbo Mode Section ................... 26
Added Figure 48 .............................................................................. 26
Changes to CS Mode, 4-Wire Turbo Mode ................................. 29
Added Figure 54 .............................................................................. 29
Changes to Figure 56 and Figure 57 ............................................. 30
Changes to Layout Guidelines Section and Evaluating the
AD4000/AD4004 Performance Section ....................................... 33
Updated Outline Dimensions........................................................ 34
Changes to Ordering Guide Section............................................. 34
10/2016—Revision 0: Initial Version
Rev. C | Page 3 of 36
AD4000/AD4004/AD4008
SPECIFICATIONS
Data Sheet
VDD = 1.71 V to 1.89 V, VIO = 1.71 V to 5.5 V, V
REF
= 5 V, all specifications T
MIN
to T
MAX
, high-Z mode disabled, span compression disabled,
turbo mode enabled, and sampling frequency (f
S
) = 2 MSPS for the AD4000, f
S
= 1 MSPS for the AD4004, and f
S
= 500 kSPS for the AD4008,
unless otherwise noted.
Table 1.
Parameter
RESOLUTION
ANALOG INPUT
Voltage Range
Operating Input Voltage
Test Conditions/Comments
Min
16
0
−0.1
−0.1
0.1 × V
REF
0.3
1
Typ
Max
Unit
Bits
V
V
V
V
nA
µA
Analog Input Current
IN+ voltage (V
IN+
) − IN− voltage (V
IN−
)
V
IN+
to GND
V
IN−
to GND
Span compression enabled
Acquisition phase, T = 25°C
High-Z mode enabled, converting dc
input at 2 MSPS
V
REF
V
REF
+ 0.1
+0.1
0.9 × V
REF
THROUGHPUT
Complete Cycle
AD4000
AD4004
AD4008
Conversion Time
Acquisition Phase
1
AD4000
AD4004
AD4008
Throughput Rate
2
AD4000
AD4004
AD4008
Transient Response
3
DC ACCURACY
No Missing Codes
Integral Nonlinearity Error (INL)
T = 0°C to 85°C
Differential Nonlinearity Error (DNL)
Transition Noise
Zero Error
Zero Error Drift
4
Gain Error
Gain Error Drift
4
Power Supply Sensitivity
1/f Noise
5
AC ACCURACY
Dynamic Range
Total RMS Noise
f
IN
= 1 kHz, −0.5 dBFS, V
REF
= 5 V
Signal-to-Noise Ratio (SNR)
Spurious-Free Dynamic Range (SFDR)
Total Harmonic Distortion (THD)
Signal-to-Noise-and-Distortion Ratio
(SINAD)
Oversampled Dynamic Range
500
1000
2000
270
290
790
1790
0
0
0
290
320
ns
ns
ns
ns
ns
ns
ns
2
1
500
150
MSPS
MSPS
kSPS
ns
Bits
LSB
LSB
LSB
LSB
LSB
ppm/°C
LSB
ppm/°C
LSB
µV p-p
dB
µV rms
dB
dB
dB
dB
dB
16
−1.0
−0.8
−0.5
−4.5
−0.55
−20
−0.92
±0.2
±0.2
±0.15
0.5
+1.0
+0.8
+0.5
+4.5
+0.55
+20
+0.92
±3
0.5
6
93.5
37
VDD = 1.8 V ± 5%
Bandwidth = 0.1 Hz to 10 Hz
91
91
Oversampling ratio (OSR) = 256,
V
REF
= 5 V
Rev. C | Page 4 of 36
93
112
−115
92.5
117
Data Sheet
Parameter
f
IN
= 1 kHz, −0.5 dBFS, V
REF
= 2.5 V
SNR
SFDR
THD
SINAD
f
IN
= 100 kHz, −0.5 dBFS, V
REF
= 5 V
SNR
THD
SINAD
f
IN
= 400 kHz, −0.5 dBFS, V
REF
= 5 V
SNR
THD
SINAD
−3 dB Input Bandwidth
Aperture Delay
Aperture Jitter
REFERENCE
Voltage Range, V
REF
Current
AD4000
AD4004
AD4008
INPUT OVERVOLTAGE CLAMP
IN+/IN− Current, I
IN+
/I
IN−
V
IN+
/V
IN−
at Maximum I
IN+
/I
IN−
V
IN+
/V
IN−
Clamp On/Off Threshold
Deactivation Time
REF Current at Maximum I
IN+
DIGITAL INPUTS
Logic Levels
Input Low Voltage, V
IL
Input High Voltage, V
IH
Input Low Current, I
IL
Input High Current, I
IH
Input Pin Capacitance
DIGITAL OUTPUTS
Data Format
Pipeline Delay
Output Low Voltage, V
OL
Output High Voltage, V
OH
POWER SUPPLIES
VDD
VIO
Standby Current
I
SINK
= 500 µA
I
SOURCE
= −500 µA
Test Conditions/Comments
Min
85.5
AD4000/AD4004/AD4008
Typ
87.5
115
−113
87
90
−95
89
85
−91
84
10
1
1
2.4
V
REF
= 5 V
2 MSPS
1 MSPS
500 kSPS
V
REF
= 5 V
V
REF
= 2.5 V
V
REF
= 5 V
V
REF
= 2.5 V
V
REF
= 5 V
V
REF
= 2.5 V
V
IN+
> V
REF
0.75
0.325
0.185
50
50
5.4
3.1
5.4
2.8
360
100
5.1
Max
Unit
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
MHz
ns
ps rms
V
mA
mA
mA
mA
mA
V
V
V
V
ns
µA
85.5
5.25
2.68
VIO > 2.7 V
VIO ≤ 2.7 V
VIO > 2.7 V
VIO ≤ 2.7 V
−0.3
−0.3
0.7 × VIO
0.8 × VIO
−1
−1
6
+0.3 × VIO
+0.2 × VIO
VIO + 0.3
VIO + 0.3
+1
+1
V
V
V
V
µA
µA
pF
Serial 16 bits, straight binary
Conversion results available
immediately after completed
conversion
0.4
VIO − 0.3
1.71
1.71
1.8
1.6
1.89
5.5
V
V
V
V
µA
VDD and VIO = 1.8 V, T = 25°C
Rev. C | Page 5 of 36
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