INTERSIL HA3-2556-9

HA-2556
Data Sheet
September 1998
File Number
2477.5
57MHz, Wideband, Four Quadrant,
Voltage Output Analog Multiplier
Features
The HA-2556 is a monolithic, high speed, four quadrant,
analog multiplier constructed in the Intersil Dielectrically
Isolated High Frequency Process. The voltage output
simplifies many designs by eliminating the current-to-voltage
conversion stage required for current output multipliers. The
HA-2556 provides a 450V/µs slew rate and maintains
52MHz and 57MHz bandwidths for the X and Y channels
respectively, making it an ideal part for use in video systems.
• Low Multiplication Error . . . . . . . . . . . . . . . . . . . . . . .1.5%
• High Speed Voltage Output . . . . . . . . . . . . . . . . . 450V/µs
The suitability for precision video applications is
demonstrated further by the Y Channel 0.1dB gain flatness
to 5.0MHz, 1.5% multiplication error, -50dB feedthrough and
differential inputs with 8µA bias current. The HA-2556 also
has low differential gain (0.1%) and phase (0.1o) errors.
The HA-2556 is well suited for AGC circuits as well as mixer
applications for sonar, radar, and medical imaging
equipment. The HA-2556 is not limited to multiplication
applications only; frequency doubling, power detection, as
well as many other configurations are possible.
• Input Bias Currents. . . . . . . . . . . . . . . . . . . . . . . . . . . 8µA
• 5MHz Feedthrough. . . . . . . . . . . . . . . . . . . . . . . . . . -50dB
• Wide Y Channel Bandwidth . . . . . . . . . . . . . . . . . . 57MHz
• Wide X Channel Bandwidth . . . . . . . . . . . . . . . . . . 52MHz
• VY 0.1dB Gain Flatness . . . . . . . . . . . . . . . . . . . . 5.0MHz
Applications
• Military Avionics
• Missile Guidance Systems
• Medical Imaging Displays
• Video Mixers
• Sonar AGC Processors
• Radar Signal Conditioning
For MIL-STD-883 compliant product consult the
HA-2556/883 datasheet.
• Voltage Controlled Amplifier
Ordering Information
Functional Block Diagram
PART NUMBER
TEMP.
RANGE (oC)
PACKAGE
• Vector Generators
PKG.
NO.
HA3-2556-9
-40 to 85
16 Ld PDIP
E16.3
HA9P2556-9
-40 to 85
16 Ld SOIC
M16.3
HA1-2556-9
-40 to 85
16 Ld CERDIP
F16.3
HA-2556
VX+
VX-
-
A
X
+
1/SF
Pinout
VOUT
+
∑
HA-2556
(PDIP, CERDIP, SOIC)
TOP VIEW
VY+
+
-
VYREF
15 VXIOB
14 NC
VYIOB 3
VYIOA 4
X
VZ+
+
-
VZ-
13 VX+
NOTE: The transfer equation for the HA-2556 is:
(VX+ -VX-) (VY+ -VY-) = SF (VZ+ -VZ-),
where SF = Scale Factor = 5V; VX, VY,
VZ = Differential Inputs.
12 VX-
Y
11 V+
VY - 6
V- 7
Z
16 VXIOA
GND 1
VREF 2
VY+ 5
Y
+-
Σ
Z
10 VZ 9 VZ +
VOUT 8
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Copyright © Intersil Corporation 1999
HA-2556
Absolute Maximum Ratings
Thermal Information
Voltage Between V+ and V- Terminals. . . . . . . . . . . . . . . . . . . . 35V
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V
Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±60mA
Thermal Resistance (Typical, Note 1)
θJA (oC/W) θJC (oC/W)
PDIP Package . . . . . . . . . . . . . . . . . . .
77
N/A
SOIC Package . . . . . . . . . . . . . . . . . . .
90
N/A
CERDIP Package. . . . . . . . . . . . . . . . .
75
20
Maximum Junction Temperature (Ceramic Package) . . . . . . . 175oC
Maximum Junction Temperature (Plastic Packages) . . . . . . 150oC
Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300oC
(SOIC - Lead Tips Only)
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
1. θJA is measured with the component mounted on an evaluation PC board in free air.
VSUPPLY = ±15V, RF = 50Ω, RL = 1kΩ, CL = 20pF, Unless Otherwise Specified
Electrical Specifications
PARAMETER
TEST CONDITIONS
TEMP. (oC)
MIN
TYP
MAX
UNITS
MULTIPLIER PERFORMANCE
Transfer Function
( V X+ – V X- ) × ( V Y+ – V Y- )
V OUT = A -------------------------------------------------------------------- – ( V Z+ – V Z- )
5
Multiplication Error
Note 2
25
-
1.5
3
%
Full
-
3.0
6
%
Multiplication Error Drift
Full
-
0.003
-
%/oC
Scale Factor
25
-
5
-
V
VX, VY = ±3V, Full Scale = 3V
25
-
0.02
-
%
VX, VY = ±4V, Full Scale = 4V
25
-
0.05
0.25
%
VX, VY = ±5V, Full Scale = 5V
25
-
0.2
0.5
%
VY = 200mVP-P, VX = 5V
25
-
57
-
MHz
VX = 200mVP-P, VY = 5V
25
-
52
-
MHz
Full Power Bandwidth (-3dB)
10VP-P
25
-
32
-
MHz
Slew Rate
Note 5
25
420
450
-
V/µs
Rise Time
Note 6
25
-
8
-
ns
Overshoot
Note 6
25
-
20
-
%
Settling Time
To 0.1%, Note 5
25
-
100
-
ns
Differential Gain
Notes 3, 8
25
-
0.1
0.2
%
Differential Phase
Notes 3, 8
25
-
0.1
0.3
Degrees
VY 0.1dB Gain Flatness
200mVP-P, VX = 5V, Note 8
25
4.0
5.0
-
MHz
VX 0.1dB Gain Flatness
200mVP-P, VY = 5V, Note 8
25
2.0
4.0
-
MHz
THD + N
Note 4
25
-
0.03
-
%
1MHz Feedthrough
200mVP-P, Other Ch Nulled
25
-
-65
-
dB
5MHz Feedthrough
200mVP-P, Other Ch Nulled
25
-
-50
-
dB
25
-
3
15
mV
Linearity Error
AC CHARACTERISTICS
Small Signal Bandwidth (-3dB)
SIGNAL INPUT (VX, VY, VZ)
Input Offset Voltage
Full
-
8
25
mV
Average Offset Voltage Drift
Full
-
45
-
µV/ oC
Input Bias Current
25
-
8
15
µA
Full
-
12
20
µA
2
HA-2556
VSUPPLY = ±15V, RF = 50Ω, RL = 1kΩ, CL = 20pF, Unless Otherwise Specified (Continued)
Electrical Specifications
PARAMETER
TEST CONDITIONS
TEMP. (oC)
MIN
TYP
MAX
UNITS
25
-
0.5
2
µA
Full
-
1.0
3
µA
Input Offset Current
Differential Input Resistance
25
-
1
-
MΩ
Full Scale Differential Input (VX, VY, VZ)
25
±5
-
-
V
VX Common Mode Range
25
-
±10
-
V
VY Common Mode Range
25
-
+9, -10
-
V
CMRR Within Common Mode Range
Full
65
78
-
dB
f = 1kHz
25
-
150
-
nV/√Hz
f = 100kHz
25
-
40
-
nV/√Hz
Note 10
Full
±5.0
±6.05
-
V
Output Current
Full
±20
±45
-
mA
Output Resistance
25
-
0.7
1.0
Ω
Voltage Noise (Note 9)
OUTPUT CHARACTERISTICS
Output Voltage Swing
POWER SUPPLY
+PSRR
Note 7
Full
65
80
-
dB
-PSRR
Note 7
Full
45
55
-
dB
Full
-
18
22
mA
Supply Current
NOTES:
2.
3.
4.
5.
6.
7.
8.
9.
10.
Error is percent of full scale, 1% = 50mV.
f = 4.43MHz, VY = 300mVP-P, 0 to 1VDC offset, VX = 5V.
f = 10kHz, VY = 1VRMS, VX = 5V.
VOUT = 0 to ±4V.
VOUT = 0 to ±100mV.
VS = ±12V to ±15V.
Guaranteed by characterization and not 100% tested.
VX = VY = 0V.
VX = 5.5V, VY = ±5.5V.
Simplified Schematic
V+
VBIAS
VBIAS
VX+
VX-
VY+
REF
VCC
VY VZ +
VZ -
OUT
+
-
VXIO A
VXIOB
3
VYIO A
GND
VYIOB
V-
HA-2556
Application Information
Operation at Reduced Supply Voltages
The HA-2556 will operate over a range of supply voltages,
±5V to ±15V. Use of supply voltages below ±12V will reduce
input and output voltage ranges. See “Typical Performance
Curves” for more information.
Offset Adjustment
X and Y channel offset voltages may be nulled by using a
20K potentiometer between the VYIO or VXIO adjust pin A
and B and connecting the wiper to V-. Reducing the channel
offset voltage will reduce AC feedthrough and improve the
multiplication error. Output offset voltage can also be nulled
by connecting VZ- to the wiper of a potentiometer which is
tied between V+ and V-.
Capacitive Drive Capability
When driving capacitive loads >20pF a 50Ω resistor should
be connected between VOUT and VZ+, using VZ+ as the
output (see Figure 1). This will prevent the multiplier from
going unstable and reduce gain peaking at high frequencies.
The 50Ω resistor will dampen the resonance formed with the
capacitive load and the inductance of the output at pin 8.
Gain accuracy will be maintained because the resistor is
inside the feedback loop.
Theory of Operation
The HA-2556 creates an output voltage that is the product
of the X and Y input voltages divided by a constant scale
factor of 5V. The resulting output has the correct polarity in
each of the four quadrants defined by the combinations of
positive and negative X and Y inputs. The Z stage provides
the means for negative feedback (in the multiplier
configuration) and an input for summation into the output.
This results in the following equation, where X, Y and Z are
high impedance differential inputs.
1
16
NC
2
15
NC
NC
3
14
NC
NC
4
13
VX+
VY+
5
6
-15V
7
+
-
+
-
Σ
+
10
9
8
50Ω
1kΩ
FIGURE 1. DRIVING CAPACITIVE LOAD
The Balance Concept
The open loop transfer equation for the HA-2556 is:
( V X+ -V X- ) x ( V Y+ – V Y- )
V OUT = A ------------------------------------------------------------------- - ( V Z+ -V Z- )
5V
where;
A
= Output Amplifier Open Loop Gain
= Fixed Scaled Factor
An understanding of the transfer function can be gained by
assuming that the open loop gain, A, of the output amplifier
is infinite. With this assumption, any value of VOUT can be
generated with an infinitesimally small value for the terms
within the brackets. Therefore we can write the equation:
+15 V
VZ VZ +
The purpose of the reference circuit is to provide a stable
current, used in setting the scale factor to 5V. This is
achieved with a bandgap reference circuit to produce a
temperature stable voltage of 1.2V which is forced across a
NiCr resistor. Slight adjustments to scale factor may be
possible by overriding the internal reference with the VREF
pin. The scale factor is used to maintain the output of the
multiplier within the normal operating range of ±5V when
full scale inputs are applied.
5V
12
11
+-
The HA-2556 takes the output current of the core and feeds it
to a transimpedance amplifier, that converts the current to a
voltage. In the multiplier configuration, negative feedback is
provided with the Z transconductance amplifier by connecting
VOUT to the Z input. The Z stage converts VOUT to a current
which is subtracted from the multiplier core before being
applied to the high gain transimpedance amp. The Z stage, by
virtue of it’s similarity to the X and Y stages, also cancels
second order errors introduced by the dependence of VBE on
collector current in the X and Y stages.
VX, VY, VZ = Differential Input Voltages
REF
NC
To accomplish this the differential input voltages are first
converted into differential currents by the X and Y input
transconductance stages. The currents are then scaled by a
constant reference and combined in the multiplier core. The
multiplier core is a basic Gilbert Cell that produces a
differential output current proportional to the product of X and
Y input signal currents. This current becomes the output for
the HA-2557.
VOUT
20pF
( V X+ -V X- ) x ( V Y+ -V Y- )
0 = ----------------------------------------------------------------- - ( V Z+ -V Z- )
5V
which simplifies to:
( V X+ -V X- ) x ( V Y+ -V Y- ) = 5V ( V Z+ -V Z- )
This form of the transfer equation provides a useful tool to
analyze multiplier application circuits and will be called the
Balance Concept.
XxY
V OUT = Z = -------------5
4
HA-2556
Typical Applications
Here the Balance equation will appear as:
Let’s first examine the Balance Concept as it applies to the
standard multiplier configuration (Figure 2).
(A) x (A) = 5(W)
VX+
A
HA-2556
VOUT
+
-
VX-
A
Y
VZ +
Z
-
-
VY-
W
X
+
1/5V
+
VOUT
A
-
VX-
+
+
∑
1/5V
VY+
HA-2556
VX+
A
+
B
W
X
VZ -
∑
-
VY+
Y
+
Z
-
VZ +
+
-
VY -
FIGURE 2. MULTIPLIER
Signals A and B are input to the multiplier and the signal W
is the result. By substituting the signal values into the
Balance equation you get:
VZ -
FIGURE 4. SQUARE
Which simplifies to:
(A) x (B) = 5(W)
A2
W = ------5
And solving for W:
AxB
W = -------------5
Notice that the output (W) enters the equation in the
feedback to the Z stage. The Balance Equation does not test
for stability, so remember that you must provide negative
feedback. In the multiplier configuration, the feedback path is
connected to VZ+ input, not VZ-. This is due to the inversion
that takes place at the summing node just prior to the output
amplifier. Feedback is not restricted to the Z stage, other
feedback paths are possible as in the Divider Configuration
shown in Figure 3.
VX-
W
X
+
VX-
W
A
X
+
1/5V
∑
-
VY+
+
Y
Z
-
VY-
VZ +
+
-
A
VZ -
Y
The Balance equation takes the form:
( W ) × ( –W ) = 5 ( –A )
∑
+
-
VOUT
A
1/5V
VY+
VOUT
+
FIGURE 5. SQUARE ROOT (FOR A > 0)
+
-
HA-2556
VX+
HA-2556
VX+
B
The last basic configuration is the Square Root as shown in
Figure 5. Here feedback is provided to both X and Y inputs.
Z
-
VZ +
Which equates to:
+
-
VZ -
VY-
A
W =
5A
FIGURE 3. DIVIDER
Inserting the signal values A, B and W into the Balance
Equation for the divider configuration yields:
The four basic configurations (Multiply, Divide, Square and
Square Root) as well as variations of these basic circuits
have many uses.
( -W ) ( B ) = 5V x ( -A )
Frequency Doubler
Solving for W yields:
For example, if ACos(ωτ) is substituted for signal A in the
Square function, then it becomes a Frequency Doubler and
the equation takes the form:
5A
W = ------B
Notice that, in the divider configuration, signal B must remain
≥0 (positive) for the feedback to be negative. If signal B is
negative, then it will be multiplied by the VX- input to produce
positive feedback and the output will swing into the rail.
Signals may be applied to more than one input at a time as
in the Squaring configuration in Figure 4:
5
( ACos ( ωτ ) ) × ( ACos ( ωτ ) ) = 5 ( W )
And using some trigonometric identities gives the result:
A2
W = ------- ( 1 + Cos ( 2ωτ ) )
10
HA-2556
Square Root
The Square Root function can serve as a precision/wide
bandwidth compander for audio or video applications. A
compander improves the Signal to Noise Ratio for your
system by amplifying low level signals while attenuating or
compressing large signals (refer to Figure 17; X0.5 curve).
This provides for better low level signal immunity to noise
during transmission. On the receiving end the original signal
may be reconstructed with the standard Square function.
Communications
The Multiplier configuration has applications in AM Signal
Generation, Synchronous AM Detection and Phase
Detection to mention a few. These circuit configurations are
shown in Figures 6, 7 and 8. The HA-2556 is particularly
useful in applications that require high speed signals on all
inputs.
ACos(ωΑτ)
VX+
HA-2556
VOUT
+
Audio
-
VX-
A
+
1/5V
CCos(ωCτ)
∑
-
VY+
+
Carrier
W
X
Y
VZ +
Z
+
-
-
VY-
VZ -
AC
W = -------- ( Cos ( ω C – ω A )τ + Cos ( ω C + ω A )τ )
10
FIGURE 6. AM SIGNAL GENERATION
AM Signal
VX+
HA-2556
VOUT
+
-
VX-
+
+
Scale Factor Control
The HA-2556 is able to operate over a wide supply voltage
range ±5V to ±17.5V. The ±5V range is particularly useful in
video applications. At ±5V the input voltage range is reduced
to ±1.4V. The output cannot reach its full scale value with this
restricted input, so it may become necessary to modify the
scale factor. Adjusting the scale factor may also be useful
when the input signal itself is restricted to a small portion of
the full scale level. Here we can make use of the high gain
output amplifier by adding external gain resistors.
Generating the maximum output possible for a given input
signal will improve the Signal to Noise Ratio and Dynamic
Range of the system. For example, let’s assume that the
input signals are 1VPEAK each. Then the maximum output
for the HA-2556 will be 200mV. (1V x 1V)/(5V) = 200mV. It
would be nice to have the output at the same full scale as
our input, so let’s add a gain of 5 as shown in Figure 9.
VX+
∑
Y
HA-2556
A
-
VY+
Although the X and Y inputs have similar AC characteristics,
they are not the same. The designer should consider input
parameters such as small signal bandwidth, AC feedthrough
and 0.1dB gain flatness to get the most performance from
the HA-2556. The Y channel is the faster of the two inputs
with a small signal bandwidth of typically 57MHz versus
52MHz for the X channel. Therefore in AM Signal
Generation, the best performance will be obtained with the
Carrier applied to the Y channel and the modulation signal
(lower frequency) applied to the X channel.
X
1/5V
Carrier
W
A
input was dedicated to a slow moving control function as is
required for Automatic Gain Control. The HA-2556 is
versatile enough for both.
VZ+
Z
-
VX-
LIKE THE FREQUENCY DOUBLER YOU GET AUDIO CENTERED AT DC
AND 2FC.
+
VX-
-
-
+
Y
-
VZ -
250Ω
RG
One caveat is that the output bandwidth will also drop by this
factor of 5. The multiplier equation then becomes:
∑
-
VY+
+
W
X
1/5V
ACos(ωτ+φ)
VZ +
1kΩ
RF
FIGURE 9. EXTERNAL GAIN OF 5
VOUT
+
Z
RF
ExternalGain = -------- + 1
RG
HA-2556
A
Y
VY-
FIGURE 7. SYNCHRONOUS AM DETECTION
+
-
VY+
B
VX+
∑
1/5V
VZ-
W
X
+
-
VY-
ACos(ωτ)
A
+
-
VOUT
+
Z
VZ +
5AB
W = ------------ = A × B
5
VZ -
Current Output
+
-
-
VY-
A2
W = ------- ( Cos ( φ ) + Cos ( 2ωτ + φ ) )
10
DC COMPONENT IS PROPORTIONAL TO COS(f)
FIGURE 8. PHASE DETECTION
Each input X, Y and Z has similar wide bandwidth and input
characteristics. This is unlike earlier products where one
6
Another useful circuit for low voltage applications allows the
user to convert the voltage output of the HA2556 to an output
current. The HA-2557 is a current output version offering
100MHz of bandwidth, but its scale factor is fixed and does not
have an output amplifier for additional scaling. Fortunately the
circuit in Figure 10 provides an output current that can be
HA-2556
scaled with the value of RCONVERT and provides an output
impedance of typically 1MΩ. The equation for IOUT becomes:
A×B
1
I OUT = -------------- × -------------------------------5
R CONVERT
Of course the HA-2556 is also well suited to standard
multiplier applications such as Automatic Gain Control and
Voltage Controlled Amplifier.
A
HA-2556
VX+
The Video Fader circuit provides a unique function. Here Ch B
is applied to the minus Z input in addition to the minus Y input.
In this way, the function in Figure 11 is generated. VMIX will
control the percentage of Ch A and Ch B that are mixed
together to produce a resulting video image or other signal.
A
VOUT
+
X
+
1/5V
VY+
B
Y
+
∑
-
5K
VZ +
Z
+
-
-
5K
VY-
5K
VZ -
IOUT
95K
X
+
R1
5K
∑
1/5V
B
-
VX-
RCONVERT
A
-
5K
A
FIGURE 12. DIFFERENCE OF SQUARES
HA-2556
VX+
VX-
W = 5(A2-B2)
+
Video Fader
-
VY+
Y
+
VX+
+
VY-
A
VZ -
+
A
∑
-
VY+
+
Y
VZ +
Z
-
VY-
The Balance equation looks like:
B
+
-
FIGURE 10. CURRENT OUTPUT
A-B
W = 100 A
X
1/5V
-
-
VOUT
+
-
VZ +
Z
HA-2556
R2
VX-
VZ -
R1 and R2 set scale to 1V/%, other scale factors possible.
For A 0V.
FIGURE 13. PERCENTAGE DEVIATION
( V MIX ) × ( ChA – ChB ) = 5 ( V OUT – ChB )
Which simplifies to:
V MIX
V OUT = ChB + -------------- ( ChA – ChB )
5
-
VX+
1
16
NC
REF
Ch B
VY-
NC
2
15
NC
NC
3
14
NC
4
NC
VX +
-15V
5
6
+
-
+
-
13
+-
7
Σ
+
10
9
8
∑
-
VY+
+
Y
Z
-
VY-
VZ +
B
A
+
-
VZ -
FIGURE 14. DIFFERENCE DIVIDED BY SUM S (For A + B ≥ 0V)
VMIX
(0V to 5V)
Automatic Gain Control
+15 V
VZ VZ +
VOUT
50Ω
FIGURE 11. VIDEO FADER
Other Applications
As shown above, a function may contain several different
operators at the same time and use only one HA-2556.
Some other possible multi-operator functions are shown in
Figures 12, 13 and 14.
7
+
5K
12
11
A
A-B
W = 10 B + A
X
1/5V
5K
VY+
VOUT
+
When VMIX is 0V the equation becomes VOUT = Ch B and
Ch A is removed, conversely when VMIX is 5V the equation
becomes VOUT = Ch A eliminating Ch B. For VMIX values
0V ≤ VMIX ≤ 5V the output is a blend of Ch A and Ch B.
Ch A
HA-2556
VX-
Figure 15 shows the HA-2556 configured in an Automatic
Gain Control or AGC application. The HA-5127 low noise
amplifier provides the gain control signal to the X input. This
control signal sets the peak output voltage of the multiplier to
match the preset reference level. The feedback network
around the HA-5127 provides a response time adjustment.
High frequency changes in the peak are rejected as noise or
the desired signal to be transmitted. These signals do not
indicate a change in the average peak value and therefore
no gain adjustment is needed. Lower frequency changes in
the peak value are given a gain of -1 for feedback to the
control input. At DC the circuit is an integrator automatically
compensating for Offset and other constant error terms.
HA-2556
This multiplier has the advantage over other AGC circuits, in
that the signal bandwidth is not affected by the control signal
gain adjustment.
HA-2556
16 NC
1
REF
NC
2
15 NC
NC
3
14 NC
NC
4
VY+
5
Wave Shaping Circuits
Wave shaping or curve fitting is another class of application
for the analog multiplier. For example, where a nonlinear
sensor requires corrective curve fitting to improve linearity
the HA-2556 can provide nonintegral powers in the range 1
to 2 or nonintegral roots in the range 0.5 to 1.0 (refer to
References). This effect is displayed in Figure 17.
1
13
X
12
+-
7
Σ
10
Z
9
8
VOUT
OUTPUT (V)
11 V+
6
V-
X0.5
0.8
Y
X0.7
0.6
0.4
X1.5
50Ω
10kΩ
X2
0.2
0.1µF
1N914
0
0.01µF
10kΩ
0
0.2
0.4
0.6
INPUT (V)
-
+
+15V
5kΩ
HA-5127
5.6V
0.8
1
FIGURE 17. EFFECT OF NONINTEGRAL POWERS / ROOTS
A multiplier can’t do nonintegral roots “exactly”, but it can
yield a close approximation. We can approximate
nonintegral roots with equations of the form:
20kΩ
0.1µF
2 + αV
V o = ( 1 – α )V IN
IN
FIGURE 15. AUTOMATIC GAIN CONTROL
1 ⁄ 2 + αV
V o = ( 1 – α )V IN
IN
HA-2556
Figure 18 compares the function VOUT = VIN0.7 to the
approximation VOUT = 0.5VIN0.5 + 0.5VIN.
16 NC
1
REF
NC 2
15 NC
NC 3
14 NC
NC 4
X
5
1
0.8
13 VX + (VGAIN)
X0.7
12
Y
7
+-
Σ
OUTPUT (V)
V-
0.6
11 V+
6
10
Z
9
8
0.5X0.5+ 0.5X
0.4
0.2
X
5kΩ
500Ω
-
VOUT
VIN
+
0
0
0.2
0.4
0.6
0.8
1
INPUT (V)
HFA0002
FIGURE 16. VOLTAGE CONTROLLED AMPLIFIER
Voltage Controlled Amplifier
A wide range of gain adjustment is available with the Voltage
Controlled Amplifier configuration shown in Figure 16. Here
the gain of the HFA0002 can be swept from 20V/V to a gain
of almost 1000V/V with a DC voltage from 0V to 5V.
8
FIGURE 18. COMPARE APPROXIMATION TO NONINTEGRAL
ROOT
This function can be easily built using an HA-2556 and a
potentiometer for easy adjustment as shown in Figures 19 and
20. If a fixed nonintegral power is desired, the circuit shown in
Figure 21 eliminates the need for the output buffer amp. These
M where M is the desired
circuits approximate the function VIN
nonintegral power or root.
HA-2556
Values for α to give a desired M root or power are as follows:
HA-2556
ROOTS - FIGURE 19
16 NC
1
REF
NC
15 NC
2
NC
14 NC
3
+
4
NC
X
+
5
+
+-
7
V-
Σ
10
Z
8
-
1-α
9
VIN
α
+
HA-5127
0V ≤ VIN ≤ 1V
FIGURE 19. NONINTEGRAL ROOTS - ADJUSTABLE
HA-2556
REF
15 NC
NC 2
14 NC
NC 3
+
NC 4
5
X
+
6
VIN
13
11 V+
+-
7
1
0.6
1.2
0.9
≈0.25
≈0.50
≈0.70
≈0.85
1.8
≈0.75
≈0.5
≈0.3
≈0.15
1.0
1
2.0
0
1.4
1.6
Similar functions can be formulated to approximate a SINE
function converter as shown in Figure 22. With a linearly
changing (0V to 5V) input the output will follow 0 degrees to 90
degrees of a sine function (0V to 5V) output. This configuration
is theoretically capable of ±2.1% maximum error to full scale.
Σ
10
Z
-
References
1-α
+
8
α
9
1.0 ≤ M ≤ 2.0
VOUT
-
0V ≤ VIN ≤ 1V
[1] Pacifico Cofrancesco, “RF Mixers and Modulators made
with a Monolithic Four-Quadrant Multiplier” Microwave
Journal, December 1991 pg. 58 - 70.
[2] Richard Goller, “IC Generates Nonintegral Roots”
Electronic Design, December 3, 1992.
+
HA-5127
HA-2556
FIGURE 20. NONINTEGRAL POWERS - ADJUSTABLE
REF
16 NC
1
REF
NC
15 NC
2
NC
3
NC
4
5
14 NC
+
X
+
-
Y
6
V-
13
+-
Σ
8
VIN
NC
2
15 NC
NC
3
14 NC
NC
4
5
VIN
V+
R1
+
+
X
+
VOUT
V-
7
0V ≤ VIN ≤ 1V
+-
Σ
8
Z
-
9
R3
R1
262
1410
10
Z
-
9
R2
R4
 2
 R3
  R2 
1  R3
V OUT = ---  ------- + 1 V IN
+  ------- + 1  --------------------- V IN
5  R4
R

 4
  R 1 + R 2
Setting:
 R3
  R2 
α =  ------- + 1  ---------------------
R
 4
  R 1 + R 2
9
+
10
FIGURE 21. NONINTEGRAL POWERS - FIXED

1  R3
1 – α = ---  ------- + 1
5  R4

R6
470
13
11 V+
-
R3 , 644
1.2 ≤ M ≤ 2.0
R2
470
- 12
Y
6
12
11
-
7
16 NC
1
HA-2556
VOUT
α
- 12
Y
V-
1.0
By adding a second HA-2556 to the circuit an improved fit
may be achieved with a theoretical maximum error of ±0.5%
as shown in Figure 23. Figure 23 has the added benefit that it
will work for positive and negative input signals. This makes a
convenient triangle (±5V input) to sine wave (±5V output)
converter.
16 NC
1
M
0
Sine Function Generators
VOUT
-
0.5 ≤ M ≤ 1.0
α
0.8
11 V+
-
M
0.5
0.7
- 12
Y
6
13
POWERS - FIGURE 20
R4, 1K
FIGURE 22. SINE-FUNCTION GENERATOR
R5
HA-2556
( 1 – 0.1284V IN )
π V IN
V OUT = V IN --------------------------------------------------- ≈ 5sin  --- ⋅ ---------
2 5 
( 0.6082 – 0.05V )
71.5K
23.1K
IN
for; 0V ≤ VIN ≤ 5V
where:
X+
Max Theoretical Error = 2.1%FS
VOUT
X-
VIN
X+
R2
5 ( 0.1284 ) = --------------------R1 + R2
R4 ;
0.6082 = --------------------R3 + R4
10K
X-
R6
5 ( 0.05 ) = --------------------R5 + R6
VOUT
HA-2556
3
5V IN – 0.05494V IN
π V IN
V OUT = ------------------------------------------------------------------- ≈ 5sin  --- ⋅ ---------
2 5 
3.18167 + 0.0177919V2
Y+
Z+
Y-
Z-
VOUT
5.71K
HA-2556
Y+
Z+
Y-
Z-
10K
IN
for; -5V ≤ VIN ≤ 5V
FIGURE 23. BIPOLAR SINE-FUNCTION GENERATOR
Max Theoretical Error = 0.5%FS
Typical Performance Curves
1.5
1
Y = -4
Y = -5
1
Y = -3
Y=0
ERROR (%FS)
ERROR (%FS)
0.5
0
Y=1
Y=3
Y = -2
0.5
Y = -1
Y=0
0
-0.5
Y=2
-0.5
Y=4
-1
Y=5
-1
-1.5
-6
-4
-2
0
X INPUT (V)
2
4
6
-6
-4
-2
0
2
4
6
X INPUT (V)
FIGURE 24. X CHANNEL MULTIPLIER ERROR
FIGURE 25. X CHANNEL MULTIPLIER ERROR
1.5
1
X = -3
X = -2
1
0.5
0.5
ERROR (%FS)
ERROR (%FS)
X = -4
X = -1
X=0
0
X=0
0
X=5
X=1
-0.5
X = -5
X=2
-0.5
-1
X=4
X=3
-1
-6
-4
-2
0
2
4
Y INPUT (V)
FIGURE 26. Y CHANNEL MULTIPLIER ERROR
10
6
-1.5
-6
-4
-2
0
2
4
Y INPUT (V)
FIGURE 27. Y CHANNEL MULTIPLIER ERROR
6
HA-2556
(Continued)
8
200
4
100
OUTPUT (mV)
OUTPUT (V)
Typical Performance Curves
0
0
-100
-4
VY = ±100mV PULSE
VX = 5VDC
VX = ±4V PULSE
VY = 5VDC
-200
-8
0ns
0ns
1µs
500ns
250ns
FIGURE 28. LARGE SIGNAL RESPONSE
4
FIGURE 29. SMALL SIGNAL RESPONSE
Y CHANNEL = 10VP-P
X CHANNEL = 5VDC
4
3
2
2
1
1
GAIN (dB)
GAIN (dB)
3
0
-1
-2
Y CHANNEL = 4VP-P
X CHANNEL = 5VDC
0
-1
-2
-3
-3
-3dB
AT 32.5MHz
-4
10K
100K
1M
-4
10M
10K
100K
FREQUENCY (Hz)
4
3
2
2
1
GAIN (dB)
GAIN (dB)
X CHANNEL = 10VP-P
Y CHANNEL = 5VDC
0
-1
1
-1
-2
-3
-3
-4
-4
1M
10M
FREQUENCY (Hz)
FIGURE 32. X CHANNEL FULL POWER BANDWIDTH
11
X CHANNEL = 4VP-P
Y CHANNEL = 5VDC
0
-2
100K
10M
FIGURE 31. Y CHANNEL FULL POWER BANDWIDTH
3
10K
1M
FREQUENCY (Hz)
FIGURE 30. Y CHANNEL FULL POWER BANDWIDTH
4
500ns
50mV/DIV.; 50ns/DIV.
2V/DIV.; 100ns/DIV.
10K
100K
1M
10M
FREQUENCY (Hz)
FIGURE 33. X CHANNEL FULL POWER BANDWIDTH
HA-2556
Typical Performance Curves
(Continued)
0
0
VY = 5VDC
VX = 5VDC
-6
GAIN (dB)
GAIN (dB)
-6
VX = 2VDC
-12
-18
VY = 2VDC
-12
-18
VY = 0.5VDC
-24
VY = 200mVP-P
VX = 0.5VDC
10K
100K
1M
10M
-24
VX = 200mVP-P
10K
100M
100K
FIGURE 34. Y CHANNEL BANDWIDTH vs X CHANNEL
-20
-30
-40
-50
CMRR (dB)
CMRR (dB)
VX +, VX - = 200mVRMS
VY = 5VDC
-10
-20
5MHz
-38.8dB
-60
-50
-60
-70
-80
-80
100K
1M
10M
5MHz
-26.2dB
-40
-70
10K
100M
10K
100K
FREQUENCY (Hz)
1M
10M
100M
FREQUENCY (Hz)
FIGURE 36. Y CHANNEL CMRR vs FREQUENCY
FIGURE 37. X CHANNEL CMRR vs FREQUENCY
0
0
VX = 200mVP-P
VY = 200mVP-P
VX = NULLED
-10
VY = NULLED
-20
FEEDTHROUGH (dB)
FEEDTHROUGH (dB)
100M
0
VY +, VY - = 200mVRMS
VX = 5VDC
-30
-20
10M
FIGURE 35. X CHANNEL BANDWIDTH vs Y CHANNEL
0
-10
-10
1M
FREQUENCY (Hz)
FREQUENCY (Hz)
-30
-40
-52.6dB
AT 5MHz
-50
-60
-70
-80
-30
-49dB
AT 5MHz
-40
-50
-60
-70
-80
10K
100K
1M
10M
FREQUENCY (Hz)
FIGURE 38. FEEDTHROUGH vs FREQUENCY
12
100M
10K
100K
1M
10M
FREQUENCY (Hz)
FIGURE 39. FEEDTHROUGH vs FREQUENCY
100M
HA-2556
Typical Performance Curves
(Continued)
14
8
13
7
BIAS CURRENT (uA)
OFFSET VOLTAGE (mV)
12
6
|VIOZ|
5
4
3
|VIOX|
2
11
10
9
8
7
6
1
5
|VIOY|
0
-100
-50
0
50
100
4
-100
150
-50
0
100
150
FIGURE 41. INPUT BIAS CURRENT (VX, VY, VZ) vs
TEMPERATURE
FIGURE 40. OFFSET VOLTAGE vs TEMPERATURE
2
6
1.5
INPUT VOLTAGE RANGE (V)
SCALE FACTOR ERROR (%)
50
TEMPERATURE (oC)
TEMPERATURE (oC)
1
0.5
0
-0.5
5
X INPUT
Y INPUT
4
3
2
1
-1
-100
-50
0
50
100
4
150
6
8
TEMPERATURE (oC)
10
12
14
16
SUPPLY VOLTAGE (±V)
FIGURE 42. SCALE FACTOR ERROR vs TEMPERATURE
FIGURE 43. INPUT VOLTAGE RANGE vs SUPPLY VOLTAGE
15
25
X INPUT
SUPPLY CURRENT (mA)
10
Y INPUT
CMR (V)
5
0
-5
X & Y INPUT
-10
-15
20
ICC
IEE
15
10
5
0
4
6
8
10
12
14
SUPPLY VOLTAGE (±V)
FIGURE 44. INPUT COMMON MODE RANGE vs SUPPLY
VOLTAGE
13
16
0
5
10
15
SUPPLY VOLTAGE (±V)
FIGURE 45. SUPPLY CURRENT vs SUPPLY VOLTAGE
20
HA-2556
Typical Performance Curves
(Continued)
MAX OUTPUT VOLTAGE (V)
5.0
4.8
4.6
4.4
4.2
100
300
500
700
900
1100
RLOAD (Ω)
FIGURE 46. OUTPUT VOLTAGE vs RLOAD
Die Characteristics
DIE DIMENSIONS:
PASSIVATION:
Type: Nitride (Si3N4) over Silox (SiO2, 5% Phos)
Silox Thickness: 12kÅ ±2kÅ
Nitride Thickness: 3.5kÅ ±2kÅ
71 mils x 100 mils x 19 mils
METALLIZATION:
Type: Al, 1% Cu
Thickness: 16kÅ ±2kÅ
TRANSISTOR COUNT:
84
SUBSTRATE POTENTIAL:
V-
Metallization Mask Layout
HA-2556
VREF GND
(2)
(1)
VXIOA
(16)
VXIOB
(15)
VYIOB
(3)
VYIOA
(4)
VX+
(13)
VY+
(5)
VX(12)
VY(6)
V+
(11)
(8)
(7)
V- VOUT
14
(9) (10)
VZ+ VZ-
HA-2556
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