|
|
PDF 420AR-32 Data sheet ( Hoja de datos )
| Número de pieza | 420AR-32 | |
| Descripción | AD420AR-32 | |
| Fabricantes | Analog Devices | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de 420AR-32 (archivo pdf) en la parte inferior de esta página. Total 12 Páginas | ||
|
No Preview Available !
a
Serial Input 16-Bit
4–20 mA, 0–20 mA DAC
AD420
FEATURES
4–20 mA, 0–20 mA or 0–24 mA Current Output
16-Bit Resolution and Monotonicity
؎0.012% max Integral Nonlinearity
؎0.05% max Offset (Trimmable)
؎0.15% max Total Output Error (Trimmable)
Flexible Serial Digital Interface (3.3 MBPS)
On-Chip Loop Fault Detection
On-Chip 5 V Reference (25 ppm/؇C max)
Asynchronous CLEAR Function
Maximum Power Supply Range of 32 V
Output Loop Compliance of 0 V to VCC – 2.5 V
24-Pin SOIC and PDIP Packages
PRODUCT DESCRIPTION
The AD420 is a complete digital to current loop output con-
verter, designed to meet the needs of the industrial control mar-
ket. It provides a high precision, fully integrated, low cost
single-chip solution for generating current loop signals in a com-
pact 24-pin SOIC or PDIP package.
The output current range can be programmed to 4 mA–20 mA,
0 mA–20 mA or an overrange function of 0 mA–24 mA. The
AD420 can alternatively provide a voltage output from a sepa-
rate pin that can be configured to provide 0 V–5 V, 0 V–10 V,
± 5 V or ± 10 V with the addition of a single external buffer
amplifier.
The 3.3M Baud serial input logic design minimizes the cost of
galvanic isolation and allows for simple connection to com-
monly used microprocessors. It can be used in three-wire or
asynchronous mode and a serial-out pin is provided to allow
daisy chaining of multiple DACs on the current loop side of the
isolation barrier.
The AD420 uses sigma-delta (Σ∆) DAC technology to achieve
16-bit monotonicity at very low cost. Full-scale settling to 0.1%
occurs within 3 ms. The only external components that are
required (in addition to normal transient protection circuitry)
are three low cost capacitors which are used in the DAC output
filter.
If the AD420 is going to be used at extreme temperatures and
supply voltages, an external output transistor can be used to
minimize power dissipation on the chip via the “BOOST” pin.
The FAULT DETECT pin signals when an open circuit occurs
in the loop. The on-chip voltage reference can be used to supply
a precision +5 V to external components in addition to the
AD420 or, if the user desires temperature stability exceeding
25 ppm/°C, an external precision reference such as the AD586
can be used as the reference.
FUNCTIONAL BLOCK DIAGRAM
VLL
REF OUT
REF IN
DATA OUT
CLEAR
LATCH
CLOCK
DATA IN
RANGE
SELECT 1
RANGE
SELECT 2
VCC
REFERENCE
4kΩ
AD420
DATA I/P
REGISTER
CLOCK
16-BIT
DAC
SWITCHED
CURRENT
SOURCES
AND
FILTERING
40Ω
BOOST
1.25kΩ
IOUT
VOUT
FAULT
DETECT
OFFSET
TRIM
CAP 1,2,3
GND
The AD420 is available in a 24-pin SOIC and PDIP over the in-
dustrial temperature range of –40°C to +85°C.
PRODUCT HIGHLIGHTS
1. The AD420 is a single chip solution for generating 4 mA–
20 mA or 0 mA–20 mA signals at the “controller end” of the
current loop.
2. The AD420 is specified with a power supply range
from 12 V to 32 V. Output loop compliance is 0 V to
VCC – 2.5 V.
3. The flexible serial input can be used in three-wire mode
with SPI* or MICROWIRE† microcontrollers, or in asyn-
chronous mode which minimizes the number of control
signals required.
4. The serial data out pin can be used to daisy chain any num-
ber of AD420s together in three-wire mode.
5. At power-up the AD420 initializes its output to the low end
of the selected range.
6. The AD420 has an asynchronous CLEAR pin which sends
the output to the low end of the selected range (0 mA,
4 mA, or 0 V).
7. The AD420 BOOST pin accommodates an external transis-
tor to off-load power dissipation from the chip.
8. The offset of ± 0.05% and total output error of ± 0.15% can
be trimmed if desired, using two external potentiometers.
*SPI is a registered trademark of Motorola.
†MlCROWIRE is a registered trademark of National Semiconductor.
REV. C
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.
© Analog Devices, Inc., 1995
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
1 page  
Pin #
2
3
4
5
6
7
8
9
10
11
14
15
16
17
18
19
20
21
22
23
1, 12, 13, 24
Symbol
VLL
FAULT DETECT
RANGE SELECT 2
RANGE SELECT 1
CLEAR
LATCH
CLOCK
DATA IN
DATA OUT
GND
REF OUT
REF IN
OFFSET TRIM
VOUT
IOUT
BOOST
CAP 1
CAP 2
CAP 3
VCC
NC
AD420
PIN DESCRIPTION
Function
Auxiliary buffered +4.5 V digital logic voltage. This pin is the internal supply
voltage for the digital circuitry and can be used as a termination for pull-up
resistors. An external +5 V power supply can be connected to VLL. It will override
this buffered voltage, thus reducing the internal power dissipation.
FAULT DETECT, connected to a pull-up resistor, is asserted low when the
output current does not match the DAC’s programmed value, for example, in
case the current loop is broken.
Selects the converter’s output operating range. One output voltage range and three
output current ranges are available.
Valid VIH will unconditionally force the output to go to the minimum of its
programmed range. After CLEAR is removed the DAC output will remain at this
value. The data in the input register is unaffected.
In the three-wire interface mode a rising edge parallel loads the serial input register
data into the DAC. To use the asynchronous mode connect LATCH through a
current limiting resistor to VCC.
Data Clock Input. The clock period is equal to the input data bit rate in the three-
wire interface mode and is 16 times the bit rate in asynchronous mode.
Serial Data Input.
Serial Data Output. In the three-wire interface mode, this output can be used for
daisy-chaining multiple AD420s. In the asynchronous mode a positive pulse will
indicate a framing error after the stop-bit is received.
Ground (Common).
+5 V Reference Output.
Reference Input.
Offset Adjust.
Voltage Output.
Current Output.
Connect to an external transistor to reduce the power dissipated in the AD420
output transistor, if desired.
These pins are used for internal filtering. Connect capacitors between each of these
pins and VCC. Refer to the description of current output operation.
Power Supply Input.
No Connection. No internal connections inside device.
DEFINITIONS OF SPECIFICATIONS
RESOLUTION: For 16-bit resolution, 1 LSB = 0.0015% of the
FSR. In the 4 mA–20 mA range 1 LSB = 244 nA.
INTEGRAL NONLINEARITY: Analog Devices defines inte-
gral nonlinearity as the maximum deviation of the actual, ad-
justed DAC output from the ideal analog output (a straight line
drawn from 0 to FS – 1 LSB) for any bit combination. This is
also referred to as relative accuracy.
DIFFERENTIAL NONLINEARITY: Differential nonlinearity
is the measure of the change in the analog output, normalized to
full scale, associated with an LSB change in the digital input code.
Monotonic behavior requires that the differential linearity error be
greater than –1 LSB over the temperature range of interest.
MONOTONICITY: A DAC is monotonic if the output either
increases or remains constant for increasing digital inputs with
the result that the output will always be a single-valued function
of the input.
GAIN ERROR: Gain error is a measure of the output error be-
tween an ideal DAC and the actual device output with all 1s
loaded after offset error has been adjusted out.
OFFSET ERROR: Offset error is the deviation of the output
current from its ideal value expressed as a percentage of the full-
scale output with all 0s loaded in the DAC.
DRIFT: Drift is the change in a parameter (such as gain and
offset) over a specified temperature range. The drift temperature
coefficient, specified in ppm/°C, is calculated by measuring the
parameter at TMIN, 25°C, and TMAX and dividing the change in
the parameter by the corresponding temperature change.
CURRENT LOOP VOLTAGE COMPLIANCE: The voltage
compliance is the maximum voltage at the IOUT pin for which
the output current will be equal to the programmed value.
REV. C
–5–
5 Page 
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
N-24
24-Lead Plastic DIP
1.275 (32.30)
1.125 (28.60)
24
1
0.210
(5.33)
MAX
PIN 1
0.200 (5.05) 0.022 (0.558)
0.125 (3.18) 0.014 (0.356)
0.100
(2.54)
BSC
13 0.280 (7.11)
12 0.240 (6.10)
0.060 (1.52)
0.015 (0.38)
0.325 (8.25)
0.300 (7.62) 0.195 (4.95)
0.115 (2.93)
0.150
(3.81)
MIN
0.070 (1.77) SEATING
0.045 (1.15) PLANE
0.015 (0.381)
0.008 (0.204)
R-24
24-Lead Small Outline (SOIC)
0.6141 (15.60)
0.5985 (15.20)
24 13
1 12
PIN 1
0.1043 (2.65)
0.0926 (2.35)
0.0291
0.0098
(0.74)
(0.25)
x
45°
0.0118 (0.30)
0.0040 (0.10)
0.0500
(1.27)
BSC
0.0192 (0.49)
0.0138 (0.35)
8°
SEATING 0.0125 (0.32) 0°
PLANE 0.0091 (0.23)
0.0500 (1.27)
0.0157 (0.40)
AD420
REV. C
–11–
11 Page | ||
| Páginas | Total 12 Páginas | |
| PDF Descargar | [ Datasheet 420AR-32.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| 420AR-32 | AD420AR-32 | Analog Devices |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |