a
FEATURES
Fast (2.4 s) 14-Bit ADC
Four Simultaneously Sampled Inputs
Four Track/Hold Amplifiers
0.35 s Track/Hold Acquisition Time
2.4 s Conversion Time per Channel
HW/SW Select of Channel Sequence for Conversion
Single Supply Operation
Selection of Input Ranges: 10 V, 5 V and 2.5 V,
0 V to 5 V and 0 V to 2.5 V
High Speed Parallel Interface Which Also Allows
Interfacing to 3 V Processors
Low Power, 115 mW Typ
Power Saving Mode, 15 W Typ
Overvoltage Protection on Analog Inputs
APPLICATIONS
AC Motor Control
Uninterruptible Power Supplies
Industrial Power Meters/Monitors
Data Acquisition Systems
Communications
GENERAL DESCRIPTION
Four-Channel, Simultaneous
Sampling, Fast, 14-Bit ADC
AD7865
FUNCTIONAL BLOCK DIAGRAM
AV
DD
V
REF
6k
TRACK/HOLD
4
SIGNAL
SCALING
SIGNAL
SCALING
SIGNAL
SCALING
SIGNAL
SCALING
V
REFAGND
DV
DD
V
DRIVE
+2.5V
REFERENCE
STBY
V
IN1A
V
IN1B
V
IN2A
V
IN2B
V
IN3A
V
IN3B
V
IN4A
V
IN4B
FRSTDATA
BUSY
EOC
DGND
AGND
RD
AD7865
MUX
14-BIT
ADC
OUTPUT
LATCH
DB13
DB0
CHANNEL
SELECT
REGISTER
DB0–DB3
CS
WR
CONVERSION
CONTROL LOGIC
INT/EXT
CLOCK
SELECT
INT
CLOCK
CONVST
SL3 SL4
H/S
CLK IN
INT/EXT
AGND AGND
SEL /SL1 CLK/SL2
The AD7865 is a fast, low power, four-channel simultaneous
sampling 14-bit A/D converter that operates from a single 5 V
supply. The part contains a 2.4
µs
successive approximation
ADC, four track/hold amplifiers, 2.5 V reference, on-chip clock
oscillator, signal conditioning circuitry and a high speed parallel
interface. The input signals on four channels are sampled simul-
taneously thus preserving the relative phase information of the
signals on the four analog inputs. The part accepts analog input
ranges of
±
10 V,
±
5 V,
±
2.5 V, 0 V to 2.5 V and 0 V to 5 V.
The part allows any subset of the four channels to be converted
in order to maximize the throughput rate on the selected sequence.
The channels to be converted can be selected either via hard-
ware (channel select input pins) or via software (programming
the channel select register).
A single conversion start signal (CONVST) simultaneously places
all the track/holds into hold and initiates conversion sequence
for the selected channels. The
EOC
signal indicates the end of
each individual conversion in the selected conversion sequence.
The BUSY signal indicates the end of the conversion sequence.
Data is read from the part via a 14-bit parallel data bus using the
standard
CS
and
RD
signals. Maximum throughput for a single
channel is 350 kSPS. For all four channels the maximum through-
put is 100 kSPS.
The AD7865 is available in a small (0.3 sq. inch area) 44-lead
PQFP.
PRODUCT HIGHLIGHTS
1. The AD7865 features four Track/Hold amplifiers and a fast
(2.4
µs)
ADC allowing simultaneous sampling and then con-
version of any subset of the four channels.
2. The AD7865 operates from a single 5 V supply and con-
sumes only 115 mW typ, making it ideal for low power and
portable applications.
3. The part offers a high speed parallel interface for easy con-
nection to microprocessors, microcontrollers and digital
signal processors.
4. The part is offered in three versions with different analog
input ranges. The AD7865-1 offers the standard industrial
ranges of
±
10 V and
±
5 V; the AD7865-2 offers a unipolar
range of 0 V to 2.5 V or 0 V to 5 V and the AD7865-3 offers
the common signal processing input range of
±
2.5 V.
5. The part features very tight aperture delay matching between
the four input sample and hold amplifiers.
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2000
AD7865–SPECIFICATIONS
Parameter
SAMPLE AND HOLD
–3 dB Full Power Bandwidth
Aperture Delay
Aperture Jitter
Aperture Delay Matching
DYNAMIC PERFORMANCE
2
Signal to (Noise + Distortion) Ratio
3
@ 25°C
AD7865-1, AD7865-3
AD7865-2
T
MIN
to T
MAX
AD7865-1, AD7865-3
AD7865-2
Total Harmonic Distortion
3, 4
Peak Harmonic or Spurious Noise
3, 4
Intermodulation Distortion
3
2nd Order Terms
3rd Order Terms
Channel-to-Channel Isolation
3, 5
DC ACCURACY
Resolution
Relative Accuracy (INL)
3
Differential Nonlinearity (DNL)
3
AD7865-1
Positive Gain Error
3
Positive Gain Error Match
3
Negative Gain Error
3
Negative Gain Error Match
3
Bipolar Zero Error
Bipolar Zero Error Match
AD7865-2
Positive Gain Error
3
Positive Gain Error Match
3
Unipolar Offset Error
3
Unipolar Offset Error Match
3
AD7865-3
Positive Gain Error
3
Positive Gain Error Match
3
Negative Gain Error
3
Negative Gain Error Match
3
Bipolar Zero Error
Bipolar Zero Error Match
ANALOG INPUTS
AD7865-1
Input Voltage Range
Input Current
AD7865-2
Input Voltage Range
Input Current
AD7865-3
Input Voltage Range
Input Current
3
20
50
4
(V
DD
= 5 V 5%, AGND = DGND = 0 V, V
REF
= Internal. Clock = Internal; all specifi-
cations T
MIN
to T
MAX
unless otherwise noted.)
B Version
3
20
50
4
Unit
MHz typ
ns max
ps typ
ns max
f
IN
= 100 kHz, f
S
= 350 kSPS
Test Conditions/Comments
A, Y Versions
1
78
77
77
76
–86
–86
–95
–95
–88
14
±
2
±
1
±
10
8
±
10
8
±
12
6
±
16
8
±
10
10
±
16
8
±
16
8
±
14
8
78
77
77
76
–86
–86
–95
–95
–88
14
±
1.5
±
1
±
8
8
±
8
8
±
10
6
±
16
8
±
10
10
±
14
8
±
14
8
±
12
6
dB min
dB min
dB min
dB min
dB max
dB max
Typically 80 dB
Typically 78 dB
fa = 49 kHz, fb = 50 kHz
dB typ
dB typ
dB max
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
LSB max
LSB max
LSB max
LSB max
f
IN
= 50 kHz Sine Wave
Any Channel
Typically 0.6 LSBs
No Missing Codes Guaranteed
Typically
±
2 LSBs
Typically 2 LSBs
Typically
±
2 LSBs
Typically 2 LSBs
Typically
±
2 LSBs
Typically 1.5 LSBs
Typically
±
2 LSBs
Typically 2 LSBs
Typically
±
2 LSBs
Typically 2 LSBs
Typically
±
6 LSBs
Typically 2 LSBs
Typically
±
6 LSBs
Typically 2 LSBs
Typically
±
5 LSBs
Typically 2 LSBs
±
5,
±
10
1, 1
±
5,
±
10
1, 1
Volts
mA max
V
IN
= –5 V and –10 V Respectively,
Typically 0.7 mA
0 V to 2.5 V,
0 V to 5 V
10
1
±
2.5
1
0 V to 2.5 V,
0 V to 5 V
10
1
±
2.5
1
Volts
µA
max
mA max
Volts
mA max
V
IN
= 2.5 V, 0 V to 2.5 V Range, Typ 1
µA
V
IN
= 5 V, 0 V to 5 V Range, Typ 0.7 mA
V
IN
= –2.5 V, Typically 0.7 mA
–2–
REV. B
AD7865
Parameter
REFERENCE INPUT/OUTPUT
V
REF
IN Input Voltage Range
V
REF
IN Input Capacitance
6
V
REF
OUT Output Voltage
V
REF
OUT Error @ 25°C
V
REF
OUT Error T
MIN
to T
MAX
V
REF
OUT Temperature Coefficient
V
REF
OUT Output Impedance
LOGIC INPUTS
Input High Voltage, V
INH
Input Low Voltage, V
INL
Input Current, I
IN
Input Capacitance, C
IN6
LOGIC OUTPUTS
Output High Voltage, V
OH
Output Low Voltage, V
OL
DB13–DB0
High Impedance
Leakage Current
Capacitance
6
Output Coding
AD7865-1, AD7865-3
AD7865-2
CONVERSION RATE
Conversion Time
Track/Hold Acquisition Time
2, 3
Throughput Time
POWER REQUIREMENTS
V
DD
I
DD
AD7865-1
Normal Mode
Standby Mode
AD7865-2
Normal Mode
Standby Mode
AD7865-3
Normal Mode
Standby Mode
Power Dissipation
AD7865-1
Normal Mode
Standby Mode
AD7865-2
Normal Mode
Standby Mode
AD7865-3
Normal Mode
Standby Mode
A, Y Versions
1
2.375/2.625
10
2.5
±
10
±
20
25
6
2.4
0.8
±
10
10
4.0
0.4
B Version
2.375/2.625
10
2.5
±
10
±
20
25
6
2.4
0.8
±
10
10
4.0
0.4
Unit
V
MIN
/V
MAX
pF max
V nom
mV max
mV max
ppm/°C typ
kΩ typ
V min
V max
µA
max
pF max
V min
V max
Test Conditions/Comments
2.5 V
±
5%
See Reference Section
V
DD
= 5 V
±
5%
V
DD
= 5 V
±
5%
I
SOURCE
= 400
µA
I
SINK
= 1.6 mA
±
10
10
±
10
10
µA
max
pF max
Two’s Complement
Straight (Natural) Binary
2.4
0.35
350
100
5
2.4
0.35
350
100
5
µs
max
µs
max
kSPS max
kSPS max
V nom
For Single Channel
For Single Channel
For All Four Channels
±
5% for Specified Performance
Typically 23 mA, Logic Inputs = 0 V or V
DD
32
20
30
20
32
20
32
20
30
20
32
20
mA max
µA
max
Typically 20 mA, Logic Inputs = 0 V or V
DD
mA max
µA
max
Typically 23 mA, Logic Inputs = 0 V or V
DD
mA max
µA
max
160
100
150
100
160
100
160
100
150
100
160
100
mW max
µW
max
mW max
µW
max
mW max
µW
max
Typically 115 mW. V
DD
= 5 V
Typically 15
µW
Typically 100 mW. V
DD
= 5 V
Typically 15
µW
Typically 115 mW. V
DD
= 5 V
Typically 15
µW
NOTES
1
Temperature ranges are as follows : A, B Versions: –40°C to +85°C, Y Version: –40°C to +105°C.
2
Performance measured through full channel (SHA and ADC).
3
See Terminology.
4
Total Harmonic Distortion and Peak Harmonic or Spurious Noise are specified at –83 dBs for the AD7865-2.
5
Measured between any two channels with the other two channels grounded.
6
Sample tested @ 25°C to ensure compliance.
Specifications subject to change without notice.
REV. B
–3–
AD7865
TIMING CHARACTERISTICS
Parameter
t
CONV
t
ACQ
t
BUSY
t
WAKE-UP
—External V
REF
t
1
t
2
Read Operation
t
3
t
4
t
5
t
6 4
t
7 5
t
8
t
9
t
10
t
11
t
12
Write Operation
t
13
t
14
t
15
t
16
t
17
External Clock
t
18
3
1, 2
(V
DD
= 5 V
5%, AGND = DGND = 0 V, V
REF
= Internal, Clock = Internal; all specifications
T
MIN
to T
MAX
unless otherwise noted.)
Unit
µs
max
µs
max
µs
max
µs
max
µs
max
ns min
ns min
ns min
ns min
ns min
ns max
ns max
ns min
ns max
ns min
ns min
ns max
ns max
ns max
ns min
ns min
ns min
ns min
ns min
ns min
ns min
Test Conditions/Comments
Conversion Time, Internal Clock
Conversion Time, External Clock (5 MHz)
Acquisition Time
Selected Number of Channels Multiplied by t
CONV
STBY
Rising Edge to
CONVST
Rising Edge
CONVST
Pulsewidth
CONVST
Rising Edge to BUSY Rising Edge
CS
to
RD
Setup Time
CS
to
RD
Hold Time
Read Pulsewidth
Data Access Time after Falling Edge of
RD,
V
DRIVE
= 5 V
Data Access Time after Falling Edge of
RD,
V
DRIVE
= 3 V
Bus Relinquish Time after Rising Edge of
RD
Time Between Consecutive Reads
EOC
Pulsewidth
RD
Rising Edge to FRSTDATA Edge (Rising or Falling)
EOC
Falling Edge to FRSTDATA Falling Delay
EOC
to
RD
Delay
WR
Pulsewidth
CS
to
WR
Setup Time
WR
to
CS
Hold Time
Input Data Setup Time of Rising Edge of
WR
Input Data Hold Time
CONVST
Falling Edge to CLK Rising Edge
A, B, Y Versions
2.4
3.2
0.35
No. of Channels
×
(t
CONV
)
1
35
70
0
0
35
35
40
5
30
15
120
180
70
15
0
20
0
0
5
5
200
NOTES
1
Sample tested at 25°C to ensure compliance. All input signals are measured with tr = tf = 1 ns (10% to 90% of 5 V) and timed from a voltage level of 1.6 V.
2
See Figures 6, 7 and 8.
3
Refer to the Standby Mode Operation section. The MAX specification of 1
µs
is valid when using a 0.1
µF
decoupling capacitor on the V
REF
pin.
4
Measured with the load circuit of Figure 1 and defined as the time required for an output to cross 0.8 V or 2.4 V.
5
These times are derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 1. The measured number is then
extrapolated back to remove the effects of charging or discharging the 50 pF capacitor. This means that the times quoted in the timing characteristics are the true bus
relinquish times of the part and as such are independent of external bus loading capacitances.
Specifications subject to change without notice.
1.6mA
TO OUTPUT
PIN
50pF
400 A
1.6V
Figure 1. Load Circuit for Access Time and Bus Relinquish Time
–4–
REV. B
AD7865
ABSOLUTE MAXIMUM RATINGS*
(T
A
= 25°C unless otherwise noted)
V
DD
to AGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
V
DD
to DGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
V
DRIVE
to DGND . . . . . . . . . . . . . . . . . . . . . . . . . V
DD
+ 0.3 V
Analog Input Voltage to AGND
AD7865-1 (± 10 V Input Range) . . . . . . . . . . . . . . . .
±
18 V
AD7865-1 (± 5 V Input Range) . . . . . . . . . . . . . . . . . .
±
9 V
AD7865-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . –1 V to +18 V
AD7865-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . –4 V to +18 V
Reference Input Voltage to AGND . . . –0.3 V to V
DD
+ 0.3 V
Digital Input Voltage to DGND . . . . . –0.3 V to V
DD
+ 0.3 V
Digital Output Voltage to DGND . . . . –0.3 V to V
DD
+ 0.3 V
Operating Temperature Range
Commercial (A, B Versions) . . . . . . . . . . . –40°C to +85°C
Automotive (Y Version) . . . . . . . . . . . . . . –40°C to +105°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . 150°C
PQFP Package, Power Dissipation . . . . . . . . . . . . . . 450 mW
θ
JA
Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 95°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
*Stresses
above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
ORDERING GUIDE
Model
AD7865AS-1
AD7865BS-1
AD7865YS-1
AD7865AS-2
AD7865BS-2
AD7865YS-2
AD7865AS-3
AD7865BS-3
AD7865YS-3
Input
Ranges
±
5 V,
±
10 V
±
5 V,
±
10 V
±
5 V,
±
10 V
0 V to 2.5 V, 0 V to 5 V
0 V to 2.5 V, 0 V to 5 V
0 V to 2.5 V, 0 V to 5 V
±
2.5 V
±
2.5 V
±
2.5 V
Relative
Accuracy
±
2 LSB
±
1.5 LSB
±
2 LSB
±
2 LSB
±
1.5 LSB
±
2 LSB
±
2 LSB
±
1.5 LSB
±
2 LSB
Temperature
Ranges
–40°C to +85°C
–40°C to +85°C
–40°C to +105°C
–40°C to +85°C
–40°C to +85°C
–40°C to +105°C
–40°C to +85°C
–40°C to +85°C
–40°C to +105°C
Package
Description
Plastic Lead Quad Flatpack
Plastic Lead Quad Flatpack
Plastic Lead Quad Flatpack
Plastic Lead Quad Flatpack
Plastic Lead Quad Flatpack
Plastic Lead Quad Flatpack
Plastic Lead Quad Flatpack
Plastic Lead Quad Flatpack
Plastic Lead Quad Flatpack
Package
Option
S-44
S-44
S-44
S-44
S-44
S-44
S-44
S-44
S-44
PIN CONFIGURATION
V
DRIVE
DGND
EOC
DB3
DB5
DV
DD
DB0
DB2
DB1
DB4
DB6
44 43 42 41 40 39 38 37 36 35 34
BUSY 1
FRSTDATA 2
CONVST
3
CS
4
RD
5
WR
6
CLK IN/SL1 7
INT/EXT
CLK/SL2
8
PIN 1
IDENTIFIER
33 DB7
32 DB8
31 DB9
30 DB10
AD7865
TOP VIEW
(Not to Scale)
29 DB11
28 DB12
27 DB13
26 AGND
25 AV
DD
24 V
REF
23 AGND
SL3 9
SL4 10
H/S
SEL 11
12 13 14 15 16 17 18 19 20 21 22
VI
N4B
V
IN3B
AGND
AGND
VI
N2A
V
IN3A
V
IN2B
V
IN1B
VI
N1A
STBY
V
IN4A
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 the AD7865 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.
WARNING!
ESD SENSITIVE DEVICE
REV. B
–5–
