1
File Number
3682.4
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
|
Copyright
Intersil Corporation 1999
HFA1245
Dual, 420MHz, Low Power, Video, Current
Feedback Operational Amplifier with
Disable
The HFA1245 is a dual, high speed, low power current
feedback amplifier built with Intersil's proprietary
complementary bipolar UHF-1 process.
The HFA1245 features individual TTL/CMOS compatible
disable controls. When pulled low they disable the
corresponding amplifier, which reduces the supply current
and forces the output into a high impedance state. This
feature allows easy implementation of simple, low power
video switching and routing systems. Component and
composite video systems also benefit from this op amp's
excellent gain flatness, and good differential gain and phase
specifications.
Multiplexed A/D applications will also find the HFA1245
useful as the A/D driver/multiplexer.
The HFA1245 is a low power, high performance upgrade for
the popular Intersil HA5022. For a dual amplifier without
disable, in a standard 8 lead pinout, please see the HFA1205
data sheet.
Pinout
HFA1245
(PDIP)
TOP VIEW
Features
Low Supply Current . . . . . . . . . . . . . . . . . 5.8mA/Op Amp
High Input Impedance . . . . . . . . . . . . . . . . . . . . . . . 2M
Low Crosstalk (5MHz) . . . . . . . . . . . . . . . . . . . . . . -83dB
High Off Isolation (5MHz) . . . . . . . . . . . . . . . . . . . . . 65dB
Wide -3dB Bandwidth (A
V
= +2) . . . . . . . . . . . . . . 420MHz
Very Fast Slew Rate . . . . . . . . . . . . . . . . . . . . . . 1200V/
s
Gain Flatness (to 50MHz) . . . . . . . . . . . . . . . . . .
0.11dB
Differential Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02%
Differential Phase . . . . . . . . . . . . . . . . . . . . 0.03 Degrees
Individual Output Enable/Disable
Output Enable/Disable Time. . . . . . . . . . . . . . 150ns/30ns
Pin Compatible Upgrade to HA5022
Applications
Flash A/D Drivers
High Resolution Monitors
Video Multiplexers
Video Switching and Routing
Professional Video Processing
Video Digitizing Boards/Systems
Multimedia Systems
RGB Preamps
Medical Imaging
Hand Held and Miniaturized RF Equipment
Battery Powered Communications
High Speed Oscilloscopes and Analyzers
Ordering Information
PART NUMBER
TEMP.
RANGE (
o
C)
PACKAGE
PKG.
NO.
HFA1245IP
-40 to 85
14 Ld PDIP
E14.3
HA5022EVAL
High Speed Op Amp DIP Evaluation Board
1
2
3
4
5
6
7
14
13
12
11
10
9
8
-IN1
+IN1
DISABLE 1
DISABLE 2
+IN2
-IN2
OUT2
NC
NC
NC
OUT1
GND
V+
+
-
+
-
V-
Data Sheet
February 1999
2
Absolute Maximum Ratings
Thermal Information
Voltage Between V+ and V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11V
DC Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
SUPPLY
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8V
Output Current (Note 2) . . . . . . . . . . . . . . . . Short Circuit Protected
30mA Continuous
60mA
50% Duty Cycle
ESD Rating
Human Body Model (Per MIL-STD-883 Method 3015.7) . . . 600V
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . -40
o
C to 85
o
C
Thermal Resistance (Typical, Note 1)
JA
(
o
C/W)
PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
100
Maximum Junction Temperature (Die) . . . . . . . . . . . . . . . . . . . 175
o
C
Maximum Junction Temperature (Plastic Package) . . . . . . . 150
o
C
Maximum Storage Temperature Range . . . . . . . . . . -65
o
C to 150
o
C
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300
o
C
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.
NOTES:
1.
JA
is measured with the component mounted on an evaluation PC board in free air.
2. Output is short circuit protected to ground. Brief short circuits to ground will not degrade reliability, however continuous (100% duty cycle) output
current must not exceed 30mA for maximum reliability.
Electrical Specifications
V
SUPPLY
=
5V, A
V
= +1, R
F
= 560
, R
S
= 650
, R
L
= 100
, Unless Otherwise Specified
PARAMETER
TEST CONDITIONS
(NOTE 3)
TEST
LEVEL
TEMP.
(
o
C)
MIN
TYP
MAX
UNITS
INPUT CHARACTERISTICS
Input Offset Voltage
A
25
-
2
5
mV
A
Full
-
3
8
mV
Average Input Offset Voltage Drift
B
Full
-
1
10
V/
o
C
Input Offset Voltage
Common-Mode Rejection Ratio
V
CM
=
1.8V
A
25
45
48
-
dB
V
CM
=
1.8V
A
85
43
46
-
dB
V
CM
=
1.2V
A
-40
43
46
-
dB
Input Offset Voltage
Power Supply Rejection Ratio
V
PS
=
1.8V
A
25
48
52
-
dB
V
PS
=
1.8V
A
85
46
50
-
dB
V
PS
=
1.2V
A
-40
46
50
-
dB
Non-Inverting Input Bias Current
A
25
-
6
15
A
A
Full
-
10
25
A
Non-Inverting Input Bias Current Drift
B
Full
-
5
60
nA/
o
C
Non-Inverting Input Bias Current
Power Supply Sensitivity
V
PS
=
1.8V
A
25
-
0.5
1
A/V
V
PS
=
1.8V
A
85
-
0.8
3
A/V
V
PS
=
1.2V
A
-40
-
0.8
3
A/V
Non-Inverting Input Resistance
V
CM
=
1.8V
A
25
0.8
2
-
M
V
CM
=
1.8V
A
85
0.5
1.3
-
M
V
CM
=
1.2V
A
-40
0.5
1.3
-
M
Inverting Input Bias Current
A
25
-
2
7.5
A
A
Full
-
5
15
A
Inverting Input Bias Current Drift
B
Full
-
60
200
nA/
o
C
Inverting Input Bias Current
Common-Mode Sensitivity
V
CM
=
1.8V
A
25
-
3
6
A/V
V
CM
=
1.8V
A
85
-
4
8
A/V
V
CM
=
1.2V
A
-40
-
4
8
A/V
Inverting Input Bias Current
Power Supply Sensitivity
V
PS
=
1.8V
A
25
-
2
5
A/V
V
PS
=
1.8V
A
85
-
4
8
A/V
V
PS
=
1.2V
A
-40
-
4
8
A/V
HFA1245
3
Inverting Input Resistance
B
25
-
56
-
Input Capacitance
B
25
-
2.0
-
pF
Input Voltage Common Mode Range
(Implied by V
IO
CMRR, +R
IN
, and -I
BIAS
CMS
Tests)
A
25, 85
1.8
2.4
-
V
A
-40
1.2
1.7
-
V
Input Noise Voltage Density (Note 6)
f = 100kHz
B
25
-
3.5
-
nV/
Hz
Non-Inverting Input Noise Current Density
(Note 6)
f = 100kHz
B
25
-
2.5
-
pA/
Hz
Inverting Input Noise Current Density
(Note 6)
f = 100kHz
B
25
-
30
-
pA/
Hz
TRANSFER CHARACTERISTICS
Open Loop Transimpedance Gain (Note 6)
B
25
-
500
-
k
AC CHARACTERISTICS
-3dB Bandwidth (V
OUT
= 0.2V
P-P
, Note 6)
A
V
= +1, +R
S
= 650
B
25
-
260
-
MHz
A
V
= +2, R
F
= 750
B
25
-
420
-
MHz
A
V
= -1, R
F
= 475
B
25
-
280
-
MHz
Full Power Bandwidth
(V
OUT
= 5V
P-P
at A
V
= +2/-1,
4V
P-P
at A
V
= +1, Note 6)
A
V
= +1, +R
S
= 650
B
25
-
150
-
MHz
A
V
= +2, R
F
= 750
B
25
-
115
-
MHz
A
V
= -1, R
F
= 475
B
25
-
160
-
MHz
Gain Flatness (A
V
= +2, R
F
= 750
,
V
OUT
= 0.2V
P-P
, Note 6)
To 25MHz
B
25
-
0.04
-
dB
To 50MHz
B
25
-
0.11
-
dB
Minimum Stable Gain
A
Full
-
1
-
V/V
Crosstalk (A
V
= +2, R
F
= 750
,
V
OUT
= 1V
P-P
, Notes 4, 6)
5MHz
B
25
-
-83
-
dB
10MHz
B
25
-
-77
-
dB
OUTPUT CHARACTERISTICS A
V
= +2, R
F
= 750
,
Unless Otherwise Specified
Output Voltage Swing (Note 6)
A
V
= -1, R
L
= 100
A
25
3
3.4
-
V
A
Full
2.8
3
-
V
Output Current (Note 6)
A
V
= -1, R
L
= 50
A
25, 85
50
60
-
mA
A
-40
28
42
-
mA
Output Short Circuit Current
B
25
-
90
-
mA
Closed Loop Output Resistance (Note 6)
DC
B
25
-
0.07
-
Second Harmonic Distortion
(V
OUT
= 2V
P-P
)
10MHz
B
25
-
-50
-
dBc
20MHz
B
25
-
-45
-
dBc
Third Harmonic Distortion
(V
OUT
= 2V
P-P
)
10MHz
B
25
-
-57
-
dBc
20MHz
B
25
-
-50
-
dBc
3rd Order Intercept (Note 6)
20MHz
B
25
-
23
-
dBm
Reverse Isolation (S
12
, Note 6)
65MHz
B
25
-
60
-
dB
TRANSIENT CHARACTERISTICS A
V
= +2, R
F
= 750
,
Unless Otherwise Specified
Rise and Fall Times (V
OUT
= 0.5V
P-P
)
Rise Time
B
25
-
0.9
-
ns
Fall Time
B
25
-
1.5
-
ns
Overshoot
(V
OUT
= 0.5V
P-P
, V
IN
t
RISE
= 1ns, Note 5)
+OS
B
25
-
5
-
%
-OS
B
25
-
10
-
%
Slew Rate (V
OUT
= 4V
P-P
, A
V
= +1,
R
F
= 560
, +R
S
= 650
)
+SR
B
25
-
1150
-
V/
s
-SR (Note 7)
B
25
-
800
-
V/
s
Electrical Specifications
V
SUPPLY
=
5V, A
V
= +1, R
F
= 560
, R
S
= 650
, R
L
= 100
, Unless Otherwise Specified (Continued)
PARAMETER
TEST CONDITIONS
(NOTE 3)
TEST
LEVEL
TEMP.
(
o
C)
MIN
TYP
MAX
UNITS
HFA1245
4
Slew Rate (V
OUT
= 5V
P-P
, A
V
= +2)
+SR
B
25
-
1400
-
V/
s
-SR (Note 7)
B
25
-
800
-
V/
s
Slew Rate
(V
OUT
= 5V
P-P
, A
V
= -1, R
F
= 475
)
+SR
B
25
-
2200
-
V/
s
-SR (Note 7)
B
25
-
1200
-
V/
s
Settling Time (V
OUT
= +2V to 0V step,
Note 6)
To 0.1%
B
25
-
15
-
ns
To 0.05%
B
25
-
20
-
ns
To 0.02%
B
25
-
40
-
ns
Overdrive Recovery Time
V
IN
=
2V
B
25
-
8.5
-
ns
VIDEO CHARACTERISTICS A
V
= +2, R
F
= 750
,
Unless Otherwise Specified
Differential Gain (f = 3.58MHz)
R
L
= 150
B
25
-
0.02
-
%
R
L
= 75
B
25
-
0.03
-
%
Differential Phase (f = 3.58MHz)
R
L
= 150
B
25
-
0.03
-
Degrees
R
L
= 75
B
25
-
0.05
-
Degrees
DISABLE CHARACTERISTICS
Disabled Supply Current
V
DISABLE
= 0V
A
Full
-
3
4
mA/Op Amp
DISABLE Input Logic Voltage
Low
A
Full
-
-
0.8
V
High
A
25, 85
2.0
-
-
V
A
-40
2.4
-
-
V
DISABLE Input Logic Low Current
V
DISABLE
= 0V
A
Full
-
100
200
A
DISABLE Input Logic High Current
V
DISABLE
= 5V
A
Full
-
1
15
A
Output Disable Time (Note 6)
V
OUT
=
1V,
V
DISABLE
= 2.4V to 0.4V
B
25
-
30
-
ns
Output Enable Time (Note 6)
V
OUT
=
1V,
V
DISABLE
= 0.4V to 2.4V
B
25
-
150
-
ns
Disabled Output Capacitance
V
DISABLE
= 0V
B
25
-
4.5
-
pF
Disabled Output Leakage (Note 6)
V
DISABLE
= 0V,
V
IN
= +2V, V
OUT
=
3V
A
Full
-
2
10
A
All Hostile Off Isolation (V
DISABLE
= 0V,
V
IN
= 1V
P-P
, A
V
= +2, Note 6)
At 5MHz
B
25
-
65
-
dB
At 10MHz
B
25
-
60
-
dB
POWER SUPPLY CHARACTERISTICS
Power Supply Range
C
25
4.5
-
5.5
V
Power Supply Current (Note 6)
A
25
5.6
5.8
6.1
mA/Op Amp
A
Full
5.4
5.9
6.3
mA/Op Amp
NOTES:
3. Test Level: A. Production Tested; B. Typical or Guaranteed Limit Based on Characterization; C. Design Typical for Information Only.
4. The typical use for these amplifiers is in multiplexed configurations, where one amplifier (hostile channel) is enabled, and the passive channel
is disabled. The crosstalk data specified is tested in this manner, with the input signal applied to the hostile channel, while monitoring the output
of the passive channel. Crosstalk performance with both the hostile and passive channels enabled is typically -63dB at 5MHz, and -58dB at
10MHz.
5. Undershoot dominates for output signal swings below GND (e.g., 0.5V
P-P
), yielding a higher overshoot limit compared to the
V
OUT
= 0V to 0.5V condition. See the "Application Information" section for details.
6. See Typical Performance Curves for more information.
7. Slew rates are asymmetrical if the output swings below GND (e.g., a bipolar signal). Positive unipolar output signals have symmetric positive
and negative slew rates comparable to the +SR specification. See the "Application Information" section, and the pulse response graphs for
details.
Electrical Specifications
V
SUPPLY
=
5V, A
V
= +1, R
F
= 560
, R
S
= 650
, R
L
= 100
, Unless Otherwise Specified (Continued)
PARAMETER
TEST CONDITIONS
(NOTE 3)
TEST
LEVEL
TEMP.
(
o
C)
MIN
TYP
MAX
UNITS
HFA1245
5
Application Information
Relevant Application Notes
The following Application Notes pertain to the HFA1245:
AN9787-An Intuitive Approach to Understanding
Current Feedback Amplifiers
AN9420-Current Feedback Amplifier Theory and
Applications
AN9663-Converting from Voltage Feedback to Current
Feedback Amplifiers
These publications may be obtained from Intersil's web site
(http://www.intersil.com) or via our AnswerFAX system.
Optimum Feedback Resistor
Although a current feedback amplifier's bandwidth
dependency on closed loop gain isn't as severe as that of a
voltage feedback amplifier, there can be an appreciable
decrease in bandwidth at higher gains. This decrease may
be minimized by taking advantage of the current feedback
amplifier's unique relationship between bandwidth and R
F
.
All current feedback amplifiers require a feedback resistor,
even for unity gain applications, and R
F
, in conjunction with
the internal compensation capacitor, sets the dominant pole
of the frequency response. Thus, the amplifier's bandwidth is
inversely proportional to R
F
. The HFA1245 design is
optimized for a 750
R
F
at a gain of +2. Decreasing R
F
decreases stability, resulting in excessive peaking and
overshoot (Note: Capacitive feedback will cause the same
problems due to the feedback impedance decrease at higher
frequencies). At higher gains the amplifier is more stable, so
R
F
can be decreased in a trade-off of stability for bandwidth.
The table below lists recommended R
F
values for various
gains, and the expected bandwidth. For good channel-to-
channel gain matching, it is recommended that all resistors
(termination as well as gain setting) be
1% tolerance or
better. Note that a series input resistor, on +IN, is required for
a gain of +1, to reduce gain peaking and increase stability.
Channel-To-Channel Frequency Response Matching
The frequency response of channel 1 and channel 2 aren't
perfectly matched. For the best channel-to-channel
frequency response match in a gain of 2 (see Figure 1), use
R
F
= 650
for channel 1 and R
F
= 806
for channel 2.
Non-inverting Input Source Impedance
For best operation, the DC source impedance seen by the
non-inverting input should be
50
. This is especially
important in inverting gain configurations where the
non-inverting input would normally be connected directly to
GND.
Pulse Undershoot and Asymmetrical Slew Rates
The HFA1245 utilizes a quasi-complementary output stage
to achieve high output current while minimizing quiescent
supply current. In this approach, a composite device
replaces the traditional PNP pulldown transistor. The
composite device switches modes after crossing 0V,
resulting in added distortion for signals swinging below
ground, and an increased undershoot on the negative
portion of the output waveform (see Figures 7, 11, 15, and
19). This undershoot isn't present for small bipolar signals,
or large positive signals. Another artifact of the composite
device is asymmetrical slew rates for output signals with a
negative voltage component. The slew rate degrades as the
output signal crosses through 0V (see Figures 7, 11, 15, and
19), resulting in a slower overall negative slew rate. Positive
only signals have symmetrical slew rates as illustrated in the
large signal positive pulse response graphs (see Figures 5,
9, 13, and 17).
DISABLE Input TTL Compatibility
The HFA1245 derives an internal GND reference for the
digital circuitry as long as the power supplies are symmetrical
about GND. With symmetrical supplies the digital switching
threshold (V
TH
= (V
IH
+ V
IL
)/2 = (2.0 + 0.8)/2) is 1.4V, which
ensures the TTL compatibility of the DISABLE input. If
asymmetrical supplies (e.g., +10V, 0V) are utilized, the
switching threshold becomes:
and the V
IH
and V
IL
levels will be V
TH
0.6V, respectively.
TABLE 1. OPTIMUM FEEDBACK RESISTOR
GAIN
(A
V
)
R
F
(
)
BANDWIDTH
(MHz)
-1
475
280
+1
560 (+RS = 650
)
260
+2
750
420
+5
200
270
+10
180
140
FREQUENCY (MHz)
NORMALIZED GAIN (dB)
1
10
100
1000
1
0
-1
-2
A
V
= +2
R
F
= 806
, CH2
R
F
= 650
, CH1
-3
-4
2
FIGURE 1. CHANNEL 1 AND CHANNEL 2 MATCHED
FREQUENCY RESPONSE
V
TH
V+
V-
+
2
-------------------
1.4V,
+
=
HFA1245
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