AD AD7400

Isolated Sigma-Delta Modulator
AD7400/AD7401
Preliminary Technical Data
FEATURES
Up to 20 MHz Data Rate (AD7401)
10 MHz Data Rate (AD7400)
2nd Order Modulator
±4 LSB INL @16 Bits
Onboard Digital Isolator
Onboard Reference
Low Power Operation:
15 mA @ 5 V
-40⬚C to +105⬚C Operating Range
16-ld SOIC Package
Safety and Regulatory Approvals
UL Recognition
3750 VRMS for 1 minute per UL 1577
CSA Component Acceptance Notice ~5A
VDE Certificate of Conformity
DIN EN 60747-5-2 (VDE 0884 Part 2):2003-01
DIN EN 60950 (VDE 0805): 2001-12; EN 60950:2000
VIORM = 840VPEAK
APPLICATIONS
AC Motor Control
Data Acquisition Systems
A/D + Opto-Isolator Replacement
GENERAL DESCRIPTION
The AD7400/AD7401 are 2nd order sigma-delta modulators
that convert an analog input signal into a high speed 1-bit data
stream with onboard digital isolation based on Analog Devices’
iCoupler® technology. The AD7400/AD7401 operate from a 5 V
power supply and accept a differential input signal of ±200 mV.
The analog input is continuously sampled by the analog
modulator, eliminating the need for external sample and hold
circuitry. The input information is contained in the output
stream as a density of ones with data rates up to 20MHz. The
original information can be reconstructed with an appropriate
digital filter. The serial I/O may use a 5V or 3V supply (VDD2).
The serial interface is digitally isolated. High-speed CMOS,
FUNCTIONAL BLOCK DIAGRAM
VDD2
VDD1
VIN+
T/H
Σ-∆ ADC
VIN-
UPDATE
ENCODE
BUF
CONTROL LOGIC
UPDATE
WATCHDOG
MDAT
DECODE
WATCHDOG
REF
ENCODE
GND1
DECODE
MCLKOUT*
GND2
*MCLKIN pin on AD7401
Rev. PrH
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 companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.326.8703
© 2004 Analog Devices, Inc. All rights reserved.
AD7400/AD7401
Preliminary Technical Data
combined with monolithic air core transformer technology, means the onboard isolation provides outstanding performance
characteristics superior to alternatives such as optocoupler devices. The parts provide an on-chip 2.5V reference. The AD7400/AD7401
are offered in a 16-lead SOIC package and have an operating temperature range of -40°C to +105°C.
TABLE OF CONTENTS
AD7400—Specifications.................................................................. 3
Pin Functional Descriptions ........................................................8
AD7401—Specifications.................................................................. 4
Theory of Operation.....................................................................9
TIMING SPECIFICATIONS1 ..................................................... 5
Outline Dimensions ....................................................................... 10
Absolute Maximum Ratings1,3......................................................... 6
REVISION HISTORY
Revision PrH: Preliminary Version
Rev. PrH | Page 2 of 10
Preliminary Technical Data
AD7400/AD7401
AD7400—SPECIFICATIONS1
Table 1. (VDD1 = VDD2 = 4.5V to 5.5V, , VIN+ = -200mV to +200mV and VIN- = 0V; TA = TMIN to TMAX, fMCLK = 10MHz unless
otherwise noted.)
Parameter
STATIC PERFORMANCE
Resolution
Integral Nonlinearity2
Differential Nonlinearity2
Offset Error2
Offset Drift vs. Temperature2
Offset Drift vs. VDD12
Absolute Reference Voltage Tolerance
Reference Voltage Matching
VREF Drift vs. Temperature2
VREF Drift vs. VDD12
ANALOG INPUT
Input Voltage Ranges6
DC Leakage Current
DYNAMIC SPECIFICATIONS
Signal to Noise + Distortion Ratio (SINAD) 2
Total Harmonic Distortion (THD)2
Peak Harmonic or Spurious Noise (SFDR)2
Effective number of bits
Isolation Transient Immunity
Signal Delay
LOGIC INPUTS
Input High Voltage, VINH
Input Low Voltage, VINL
Input Current, IIN
Input Capacitance, CIN3
LOGIC OUTPUTS
Output High Voltage, VOH
Output Low Voltage, VOL
POWER REQUIREMENTS
VDD1
VDD2
IDD17
IDD27
B Version1,5
Units
Test Conditions/Comments
When Tested with Sinc3 Filter4
16
±4
±0.9
±0.5
5
2
Filter output trunctaed to 16 Bits
0.05
±1
±TBD
60
0.2
Bits min
LSB max
LSB max
mV max
µV/⬚C max
µV/⬚C typ
mV/V typ
%min/max
%min/max
ppm/⬚C typ
% typ
±200
±1
mV min/max
µA max
70
76
-80
-70
12
15
20
20
24
dBmin
dB typ
2
0.8
±1
10
V min
V max
µA max
pF max
dB typ
dB typ
Bits
kV/µs min
kV/µs typ
µs typ
µs max
VDD2 – 0.1
0.4
V min
V max
+4.5/+5.5
+4.5/+5.5
+2.7/+3.3
18.1
1.96
Vmin/Vmax
Vmin/Vmax
Vmin/Vmax
mA max
mA max
NOTES
1
Temperature ranges as follows: -40⬚C to +105⬚C
2
See Terminology section.
3
Sample tested @ 25⬚C to ensure compliance.
4
Filter as defined by Verilog Code.
5
All voltages are relative to their respective ground.
6
Beyond the full-scale input range the output is either all zeroes or all ones.
Specifications subject to change without notice.
Rev. PrH | Page 3 of 10
Guaranteed No Missed Codes to 15 bits
Bipolar Input Range
When Tested with Sinc3 Filter4
VIN+ = 35Hz, 400mVpk-pk sine wave
Delay through filter varies with actual value of onboard clock. Decimation by 2.
IO = -20 µA
IO = 20 µA
VDD1 = 5V, Digital I/Ps = 0 V or VDD1
AD7400/AD7401
Preliminary Technical Data
AD7401—SPECIFICATIONS3
Table 2. (VDD1 = VDD2 = 4.5V to 5.5V, , VIN+ = -200mV to +200mV and VIN- = 0V; TA = TMIN to TMAX, fMCLK = 20MHz unless
otherwise noted.)
Parameter
STATIC PERFORMANCE
Resolution
Integral Nonlinearity2
Differential Nonlinearity2
Offset Error2
Offset Drift vs. Temperature2
Offset Drift vs. VDD12
Absolute Reference Voltage Tolerance
Reference Voltage Matching
VREF Drift vs. Temperature2
VREF Drift vs. VDD12
ANALOG INPUT
Input Voltage Ranges6
DC Leakage Current
DYNAMIC SPECIFICATIONS
Signal to Noise + Distortion Ratio (SINAD) 4
Total Harmonic Distortion (THD)2
Peak Harmonic or Spurious Noise (SFDR)2
Effective number of bits
Isolation Transient Immunity
Signal Delay
LOGIC INPUTS
Input High Voltage, VINH
Input Low Voltage, VINL
Input Current, IIN
Input Capacitance, CIN3
LOGIC OUTPUTS
Output High Voltage, VOH
Output Low Voltage, VOL
POWER REQUIREMENTS
VDD1
VDD2
IDD17
IDD27
B Version1,5
Units
Test Conditions/Comments
When Tested with Sinc3 Filter4
16
±4
±0.9
±0.5
5
2
Filter output trunctaed to 16 Bits
0.05
±1
±TBD
60
0.2
Bits min
LSB max
LSB max
mV max
µV/⬚C max
µV/⬚C typ
mV/V typ
%min/max
%min/max
ppm/⬚C typ
% typ
±200
±1
mV min/max
µA max
Guaranteed No Missed Codes to 15 bits
Bipolar Input Range
When Tested with Sinc3 Filter4
VIN+ = 35Hz, 400mVpk-pk sine wave
70
76
-80
-70
12
15
20
10
12
dBmin
dB typ
2
0.8
±1
10
V min
V max
µA max
pF max
VDD2 – 0.1
0.4
V min
V max
IO = -20 µA
IO = 20 µA
+4.5/+5.5
+4.5/+5.5
+2.7/+3.3
21.2
3.92
Vmin/Vmax
Vmin/Vmax
Vmin/Vmax
mA max
mA max
VDD1 = 5V, Digital I/Ps = 0 V or VDD1
dB typ
dB typ
Bits
kV/µs min
kV/µs typ
µs typ
µs max
NOTES
3
Temperature ranges as follows: -40⬚C to +105⬚C
4
See Terminology section.
3
Sample tested @ 25⬚C to ensure compliance.
4
Filter as defined by Verilog Code.
5
All voltages are relative to their respective ground.
6
Beyond the full-scale input range the output is either all zeroes or all ones.
Specifications subject to change without notice.
Rev. PrH | Page 4 of 10
Delay through filter varies with actual value of onboard clock. Decimation by 2.
Preliminary Technical Data
AD7400/AD7401
TIMING SPECIFICATIONS1
Table 3. AD7400/AD7401 Timing Specifications (VDD1 = VDD2 = 4.5V to 5.5V, TA = TMAX to TMIN unless otherwise noted.)
Parameter
FMCLKOUT
TMCLKIN2
t13
t23
t3
t4
Limit at TMIN, TMAX
10
8.2/13.2
1
20
30
15
0.4 x tMCLKIN
0.4 x tMCLKIN
Unit
MHz typ
MHz min/max
MHz min
MHz max
ns max
ns min
ns max
ns max
Description
AD7400
AD7401
Data Access Time after MCLK Rising Edge
Data Hold Time after MCLK Rising Edge
Master Clock Low Time
Master Clock High Time
NOTES
1
Sample tested @ 25⬚C to ensure compliance. All input signals are specified with tr = tf = 5ns (10% to 90% of VDD1) and timed form a voltage level of 1.6 Volts. See Figure
1.
2
Mark Space ratio for the MCLKIN input is 40/60 to 60/40.
3
Measured with the load circuit of Figure 1 and defined as the time required for the output to cross 0.8V or 2.0V.
200µA
IOL
TO
OUTPUT
PIN
+1.6V
CL
50pF
200µA
IOH
Figure 1. Load Circuit for Digital Output Timing Specifications
t4
MCLKIN /
MCLKOUT
t1
t2
t3
MDAT
Figure 2. Data Timing
Rev. PrH | Page 5 of 10
AD7400/AD7401
Preliminary Technical Data
ABSOLUTE MAXIMUM RATINGS1,3
Table 4. AD7400/AD7401 Absolute Maximum Ratings (TA = +25°C unless otherwise noted)
VDD1 to GND1
VDD2 to GND2
Analog Input Voltage to GND1
Digital Input Voltage to GND2
Output Voltage to GND2
Input Current to Any Pin Except Supplies2
Operating Temperature Range
Storage Temperature Range
Junction Temperature
SOIC Package
θJA Thermal Impedance
θJC Thermal Impedance
Resistance (Input-Output), RI-O
-0.3 V to +6.5V
-0.3 V to +6.5 V
-0.3 V to VDD1 +0.3V
-0.3 V to VDD2 +0.5 V
-0.3 V to VDD2 +0.3V
±10mA
-40°C to +105°C
-65°C to +150°C
+150°C
Capacitance (Input-Output), CI-O
Lead Temperature, Soldering
Vapor Phase (60 sec)
Infared (15 sec)
ESD
1pF
+215°C
+220°C
TBD
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause
permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those
indicated in the operational section of this specification is not implied.
Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
2
Transient currents of up to 100mA will not cause SCR latch up.
3
All voltages are relative to their respective ground.
89.2 °C/W
55.6 °C/W
1012Ω
REGULATORY INFORMATION
(PENDING)
Table 5. Insulation and Safety Related Specifications
Parameter
Input-Output Withstand Momentary
Withstand Voltage1
Minimum External Air Gap
(Clearance)
Minimum External Tracking
(Creepage)
Minimum Internal Gap (Internal
Clearance)
Tracking Resistance (Comparative
Tracking Index)
Isolation Group
Symbol
VISO
Value
3750 min.
Units
V
Conditions
Note 1
L(I01)
8.4 min
mm
L(I02)
8.1 min
mm
0.025 min
mm
Measured from input terminals to output terminals, shortest
distance through air.
Measured from input terminals to output terminals, shortest
distance path along body.
Insulation distance through insulation.
CTI
>175
V
IIIa
DIN IEC 112/VDE 0303 Part 1
Material Group (DIN VDE 0110,1/89,Table 1)
UL1
Recognized under 1577
component recognition program1
CSA
Approved under CSA Component
Acceptance Notice #5A
VDE2
Certified according to DIN EN 60747-5-2
(VDE 0884 Part 2):2003-012
Double insulation, 3750 V rms
isolation voltage
Reinforced insulation per
CSA 60950-1-03 and IEC 60950-1,
630 V rms maximum working voltage
Basic insulation, 891 V peak
Complies with DIN EN 60747-5-2 (VDE 0884 Part 2):2003-01,
DIN EN 60950 (VDE 0805):2001-12; EN 60950:2000
Reinforced insulation, 891 V peak
NOTES
1
In accordance with UL1577, each AD7400/AD7401 is proof tested by applying an insulation test voltage ≥ 4500 V rms for 1 second (current leakage detection limit =
5 µA).
2
In accordance with DIN EN 60747-5-2, each AD7400/AD7401 is proof tested by applying an insulation test voltage ≥ 1670 V peak for 1 second (partial discharge
detection limit = 5 pC).
Rev. PrH | Page 6 of 10
Preliminary Technical Data
AD7400/AD7401
DIN EN 60747-5-2 (VDE 0884 PART 2) INSULATION CHARACTERISTICS (PENDING)
Table 6.
Description
Installation classification per DIN VDE 0110
For Rated Mains Voltage ≤ 300 V rms
For Rated Mains Voltage ≤ 600 V rms
Climatic Classification
Pollution Degree (DIN VDE 0110, Table 1)
Maximum Working Insulation Voltage
Input to Output Test Voltage, Method b1
VIORM × 1.875 = VPR, 100% Production Test,
tm = 1 sec, Partial Discharge < 5 pC
Input to Output Test Voltage, Method a
After Environmental Tests Subgroup 1)
VIORM × 1.6 = VPR, tm = 60 sec, Partial Discharge < 5p C
After Input and/or Safety Test Subgroup 2/3)
VIORM × 1.2 = VPR, tm = 60 sec, Partial Discharge < 5p C
Highest Allowable Overvoltage
(Transient Overvoltage, tTR = 10 sec)
Safety-Limiting Values (Maximum value allowed in the event of a failure, also see Thermal
Derating Curve)
Case Temperature
Side 1 Current
Side 2 Current
Insulation Resistance at TS, VIO = 500 V
Symbol
Characteristic
Unit
I–IV
I–III
40/105/21
2
VIORM
VPR
891
1670
Vpeak
V peak
VPR
1426
Vpeak
1069
Vpeak
VTR
6000
V peak
TS
IS1
IS2
RS
150
TBD
TBD
>109
°C
mA
mA
Ω
This isolator is suitable for “basic electrical isolation” only within the safety limit data. Maintenance of the safety data shall be ensured by
means of protective circuits.
"*" marking on packages denotes DIN EN 60747-5-2 approval for 891 V peak working voltage.
Rev. PrH | Page 7 of 10
AD7400/AD7401
VDD1 1
VIN+ 2
VIN- 3
AD7400
NC 4
Preliminary Technical Data
16 GND2
VDD1 1
15 NC
VIN+ 2
VIN- 3
14
VDD2
13 MCLKOUT
TOP VIEW
NC 5 (Not to Scale) 12 NC
NC 6
11 MDAT
VDD1 7
10 NC
GND1 8
9
GND2
16 GND2
15 NC
AD7401
NC 4
14
VDD2
13 MCLKIN
TOP VIEW
NC 5 (Not to Scale) 12 NC
NC 6
11 MDAT
VDD1 7
10 NC
GND1 8
9
GND2
Pin Functional Descriptions
Table 7. AD7400/AD7401 Pin Function Descriptions
Pin
Number
1,7
AD7400
Pin
Mnemonic
VDD1
AD7401 Pin
Mnemonic
Description
VDD1
Supply Voltage, 5 V ±10%. This is the supply voltage for the isolated side of the
AD7400/AD7401 and is relative to GND1.
Positive analog Input, range of ±200 mV .
Negative analog input (normally connected to GND1).
Master Clock. Logic Input. An external clock is applied at this pin. A serial clock input from
1MHz to 20MHz may be applied to this pin on the AD7401. The bit stream form the
modultaor is valid on the rising edge of MCLKIN.
Master Clock. Logic Output, 10MHz typical. The bit stream form the modultaor is valid on the
rising edge of MCLKOUT on the AD7400.
Supply Voltage, 5 V ±10% or 3V ±10%. This is the supply voltage for the non-isolated side of
the AD7400/AD7401 and is relative to GND2.
Ground. This is the ground reference point for all circuitry on the isolated side of the
AD7400/AD7401.
Ground. This is the ground reference point for all circuitry on the non-isolated side of the
AD7400/AD7401.
No Connect
2
3
18
VIN+
VIN-
VIN+
VINMCLKIN
18
MCLKOUT
14
VDD2
VDD2
8
GND1
GND1
9,16
GND2
GND2
4-6,10,12,15
NC
NC
Rev. PrH | Page 8 of 10
Preliminary Technical Data
AD7400/AD7401
Theory of Operation
CIRCUIT INFORMATION
The AD7400/AD7401 Isolated Sigma-Delta Modulator converts
an analog input signal into a high-speed, (10MHz using onboard MCLK on AD7400, or up to 20MHz using external
MCLK on AD7401), single-bit data stream; the time average of
the modulator’s single-bit data is directly proportional to the
ISOLATED
+5V
NON-ISOLATED
+5V/+3V
VDD1
+
INPUT
CURRENT
RSHUNT
input signal. Figure 4 shows a typical application circuit where
the AD7400/AD7401 is used to provide isolation between the
analog input, a current sensing resistor, and the digital output
which is then processed by a digital filter to provide an N-bit
word.
VIN+
VIN-
AD7400
VDD
VDD2
SIGMADELTA
MOD/
ENCODER
SINC3 FILTER
DECODER
MDAT
MDAT
MCLKOUT
MCLK
MCLKIN
DECODER
GND1
ENCODER
GND2
(UP TO 20MHz
with AD7401)
Figure 4. Typical Application Circuit
Table 8. Analog Input Range
Analog Input
Voltage Input
Full Scale Range
640 mV
+Full Scale
+320 mV
+ Specified Input range
+200 mV
Zero
0 mV
-Specified Input range
-200 mV
-Full Scale
-320mV
Rev. PrH | Page 9 of 10
CCLK
GND
+5
SCLK
SDAT
AD7400/AD7401
Preliminary Technical Data
OUTLINE DIMENSIONS
$
'
&
0.1043 (2.65)
0.0925 (2.35)
PIN 1
0.0118 (0.30)
0.0039 (0.10)
0.0500
(1.27)
BSC
0.2992 (7.60)
0.2913 (7.40)
0.4193 (10.65)
0.3937 (10.00)
0.4134 (10.50)
0.3976 (10.10)
0.0201 (0.51)
SEATING
0.0130 (0.33) PLANE
0.0295 (0.75)
x 45°
0.0098 (0.25)
0.0126 (0.32)
0.0091 (0.23)
8° 0.0500 (1.27)
0° 0.0157 (0.40)
Figure 2. 16-Lead Short Outline Package [SOIC] Wide Body (RW-16)—Dimensions shown in millimeters
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the
human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Ordering Guide
AD7266 Products
AD7400BRW
AD7401BRW
Temperature Package
–40°C to +105°C
–40°C to +105°C
Package Description
Short Outline I.C. Package
Short Outline I.C. Package
© 2004 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective companies.
Printed in the U.S.A.
PR04718-0-3/04(PrH)
Rev. PrH | Page 10 of 10
Package Outline
RW-16
RW-16