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PDF AD734 Data sheet ( Hoja de datos )
| Número de pieza | AD734 | |
| Descripción | 10 MHz/ 4-Quadrant Multiplier/Divider | |
| Fabricantes | Analog Devices | |
| Logotipo |  |
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FEATURES
High accuracy
0.1% typical error
High speed
10 MHz full power bandwidth
450 V/μs slew rate
200 ns settling to 0.1% at full power
Low distortion
−80 dBc from any input
Third-order IMD typically −75 dBc at 10 MHz
Low noise
94 dB SNR, 10 Hz to 20 kHz
70 dB SNR, 10 Hz to 10 MHz
Direct division mode
2 MHz BW at gain of 100
APPLICATIONS
High performance replacement for AD534
Multiply, divide, square, square root
Modulators, demodulators
Wideband gain control, rms-to-dc conversion
Voltage-controlled amplifiers, oscillators, and filters
Demodulator with 40 MHz input bandwidth
GENERAL DESCRIPTION
The AD734 is an accurate high speed, four-quadrant analog
multiplier that is pin compatible with the industry-standard
AD534 and provides the transfer function W = XY/U. The
AD734 provides a low impedance voltage output with a full
power (20 V p-p) bandwidth of 10 MHz. Total static error
(scaling, offsets, and nonlinearities combined) is 0.1% of full
scale. Distortion is typically less than −80 dBc and guaranteed.
The low capacitance X, Y, and Z inputs are fully differential.
In most applications, no external components are required to
define the function.
The internal scaling (denominator) voltage, U, is 10 V, derived
from a buried-Zener voltage reference. A new feature provides
the option of substituting an external denominator voltage,
allowing the use of the AD734 as a two-quadrant divider with a
1000:1 denominator range and a signal bandwidth that remains
10 MHz, Four-Quadrant
Multiplier/Divider
AD734
FUNCTIONAL BLOCK DIAGRAM
AD734
X1
XIF
X2
X = X1 – X2
HIGH ACCURACY
TRANSLINEAR CORE
DD
U0
DENOMINATOR U
CONTROL
XZ
U
+ XY ÷ U – Z
WIF
–
W
U1 ER
AO ∞
RU
U2
Y1
YIF
Y2
Y = Y1 – Y2
Z = Z1 – Z2 ZIF
Z1
Z2
Figure 1.
10 MHz to a gain of 20 dB, 2 MHz at a gain of 40 dB, and 200 kHz
at a gain of 60 dB, for a gain-bandwidth product of 200 MHz.
The advanced performance of the AD734 is achieved by a
combination of new circuit techniques, the use of a high speed
complementary bipolar process, and a novel approach to laser
trimming based on ac signals rather than the customary dc
methods. The wide bandwidth (>40 MHz) of the AD734’s input
stages and the 200 MHz gain-bandwidth product of the multiplier
core allow the AD734 to be used as a low distortion demodulator
with input frequencies as high as 40 MHz as long as the desired
output frequency is less than 10 MHz.
The AD734AQ and AD734BQ are specified for the industrial
temperature range of −40°C to +85°C and come in a 14-lead
CERDIP and a 14-lead PDIP package. The AD734SQ/883B,
available processed to MIL-STD-883B for the military range of
−55°C to +125°C, is available in a 14-lead CERDIP.
Rev. E
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.
Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2011 Analog Devices, Inc. All rights reserved.
1 page  
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
Supply Voltage
Internal Power Dissipation
for TJ max = 175°C
X, Y, and Z Input Voltages
Output Short-Circuit Duration
Storage Temperature Range
Q-14
N-14
Operating Temperature Range
AD734A, AD734B (Industrial)
AD734S (Military)
Lead Temperature Range (Soldering, 60 sec)
Transistor Count
ESD Rating
Rating
±18 V
500 mW
VN to VP
Indefinite
−65°C to +150°C
−65°C to +150°C
−40°C to +85°C
−55°C to +125°C
+300°C
81
500 V
AD734
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; 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.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Table 3. Thermal Resistance
Package Type
14-Lead PDIP (N-14)
14-Lead CERDIP (Q-14)
θJA Unit
150 °C/W
110 °C/W
ESD CAUTION
W
12
DD
13
VP
14
X1 1
2
X2
0.093 (2.3622)
Z1
11
Z2
10
ER
9
8 VN
0.122
(3.0988)
7 Y2
6
Y1
34
5
U1
U0
U2
Figure 2. Chip Dimensions and Bonding Diagram, Dimensions shown in inches and (mm), (Contact factory for latest dimensions)
Rev. E | Page 5 of 20
5 Page 
AD734
Most of the functions of the AD734 (including division, unlike
the AD534 in this respect) are realized with Z1 connected to W.
Therefore, substituting W in place of Z1 in Equation 2 results in
an output.
W
=
(X1
−
X 2 )(Y1
U
− Y2
)
+
Z2
(3)
The free input, Z2, can be used to sum another signal to the
output; in the absence of a product signal, W simply follows the
voltage at Z2 with the full 10 MHz bandwidth. When not needed
for summation, Z2 should be connected to the ground
associated with the load circuit. The allowable polarities can be
shown in the following shorthand form:
(±W) = (±X)(±Y ) + ± Z
(+U )
(4)
In the recommended direct divider mode, the Y input is set to a
fixed voltage (typically 10 V) and U is varied directly; it can have
any value from 10 mV to 10 V. The magnitude of the ratio X/U
cannot exceed 1.25; for example, the peak X input for U = 1 V is
±1.25 V. Above this level, clipping occurs at the positive and
negative extremities of the X input. Alternatively, the AD734
can be operated using the standard (AD534) divider connections
(see Figure 27), when the negative feedback path is established
via the Y2 input. Substituting W for Y2 in Equation 2,
(( ))W = U
Z2 − Z1
X1 − X2
+ Y1
(5)
In this case, note that the variable X is now the denominator,
and the previous restriction (X/U ≤ 1.25) on the magnitude of
the X input does not apply. However, X must be positive for the
feedback polarity to be correct. Y1 can be used for summing
purposes or connected to the load ground if not needed. The
shorthand form in this case is
(±W) = (+U) (±Z) + (±Y )
(+ X )
(6)
In some cases, feedback can be connected to two of the available
inputs. This is true for the square-rooting connections (see
Figure 28), where W is connected to both X1 and Y2. Set X1 =
W and Y2 = W in Equation 2, and anticipating the possibility of
again providing a summing input, set X2 = S and Y1 = S, so that,
in shorthand form,
(±W) = (+U)(+Z) + (±S)
(7)
This is seen more generally to be the geometric-mean function,
because both U and Z can be variable; operation is restricted to
one quadrant. Feedback can also be taken to the U interface.
Full details of the operation in these modes is provided in the
Wideband RMS-to-DC Converter Using U Interface section.
DIRECT DENOMINATOR CONTROL
A valuable new feature of the AD734 is the provision to replace
the internal denominator voltage, U, with any value from 10 mV to
10 V. This can be used
• To simply alter the multiplier scaling, thus improve accu-
racy and achieve reduced noise levels when operating with
small input signals.
• To implement an accurate two-quadrant divider, with a
1000:1 gain range and an asymptotic gain-bandwidth
product of 200 MHz.
• To achieve certain other special functions, such as
AGC or rms.
Figure 21 shows the internal circuitry associated with
denominator control. Note, first, that the denominator is
actually proportional to a current, Iu, having a nominal value of
356 μA for U = 10 V, whereas the primary reference is a voltage,
generated by a buried-Zener circuit and laser-trimmed to have a
very low temperature coefficient. This voltage is nominally 8 V
with a tolerance of ±10%.
U0 3
U1 4
U2 5
NOMINALLY
Iu
356µA for
U = 10V
AD734
+
VP
14
LINK TO
DISABLE
Qu Qd
Ru
28kΩ
Rd
NOM
22.5kΩ
Rr
TC 100kΩ
NOM
8V
Qr
13
DD
9 ER
8 VN
NEGATIVE SUPPLY
Figure 21. Denominator Control Circuitry
After temperature-correction (block TC), the reference voltage
is applied to Transistor Qd and trimmed Resistor Rd, which
generate the required reference current. Transistor Qu and
Resistor Ru are not involved in setting up the internal denomina-
tor, and their associated control pins, U0, U1, and U2, are
normally grounded. The reference voltage is also made
available, via the 100 kΩ resistor, Rr, at Pin 9 (ER).
When the control pin, DD (denominator disable), is connected
to VP, the internal source of Iu is shut off, and the collector
current of Qu must provide the denominator current. The resistor
Ru is laser-trimmed such that the multiplier denominator is
exactly equal to the voltage across it (that is, across Pin U1 and
Pin U2). Note that this trimming only sets up the correct
internal ratio; the absolute value of Ru (nominally 28 kΩ) has a
tolerance of ±20%. Also, the alpha of Qu (typically 0.995), which
may be seen as a source of scaling error, is canceled by the alpha of
other transistors in the complete circuit.
In the simplest scheme (see Figure 22), an externally provided
control voltage, VG, is applied directly to U0 and U2 and the
resulting voltage across Ru is therefore reduced by one VBE. For
example, when VG = 2 V, the actual value of U is about 1.3 V.
Rev. E | Page 11 of 20
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet AD734.PDF ] | |
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