1
TM
File Number
4863
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
|
Intersil and Design is a trademark of Intersil Corporation.
|
Copyright
Intersil Corporation 2000
HFA1155
380MHz, SOT-23, Low Power Current
Feedback Operational Amplifier
The HFA1155 is a low power, high-speed op amp and is the
most recent addition to Intersil's HFA1XX5 series of low
power op amps and buffers. Intersil's proprietary
complementary bipolar UHF-1 process, coupled with the
current feedback architecture deliver superb bandwidth even
at very high gains (>250MHz at A
V
= 10). The excellent
video parameters make this amplifier ideal for professional
video applications.
Though specified for
5V operation, the HFA1155 operates
with single supply voltages as low as 4.5V, and requires only
1.4mA of I
CC
in 5V applications (see Application Information
section, and Application Note AN9897).
For a lower distortion, higher bandwidth amplifier in a SOT-
23 package, please refer to the HFA1150 data sheet.
Features
Low Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5mA
Low Distortion (10MHz, HD2). . . . . . . . . . . . . . . . . -53dBc
-3dB Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . 380MHz
High Slew Rate. . . . . . . . . . . . . . . . . . . . . . . . . . 1700V/
s
Fast Settling Time (0.1%) . . . . . . . . . . . . . . . . . . . . . 30ns
Excellent Gain Flatness . . . . . . . . . . .
0.04dB to 50MHz
High Output Current . . . . . . . . . . . . . . . . . . . . . . . . . 55mA
Fast Overdrive Recovery . . . . . . . . . . . . . . . . . . . . . <7ns
Operates with 5V Single Supply (See AN9897)
Applications
Video Switching and Routing
Pulse and Video Amplifiers
IF Signal Processing
Flash A/D Driver
Medical Imaging Systems
Related Literature
- AN9420, Current Feedback Theory
- AN9897, Single 5V Supply Operation
Pinouts
HFA1155
(SOIC)
TOP VIEW
HFA1155
(SOT23)
TOP VIEW
Ordering Information
PART NUMBER
(BRAND)
TEMP.
RANGE (
o
C)
PACKAGE
PKG. NO.
HFA1155IB
(H1155I)
-40 to 85
8 Ld SOIC
M8.15
HFA1155IB96
(H1155I)
-40 to 85
8 Ld SOIC
Tape and Reel
M8.15
HFA1155IH96
(1155)
-40 to 85
5 Ld SOT-23
Tape and Reel
P5.064
HFA11XXEVAL
DIP Evaluation Board for High-Speed Op
Amps
OPAMPSOT23EVAL
SOT-23 Evaluation Board for High-Speed Op
Amps
NC
-IN
+IN
V-
1
2
3
4
8
7
6
5
NC
V+
OUT
NC
+
-
1
2
3
5
4
+ -
V-
V+
-IN
+IN
OUT
Data Sheet
June 2000
2
Absolute Maximum Ratings
T
A
= 25
o
C
Thermal Information
Voltage Between V+ and V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
SUPPLY
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5V
Output Current (50% Duty Cycle) . . . . . . . . . . . . . . . . . . . . . . 60mA
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)
SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
175
SOT-23 Package . . . . . . . . . . . . . . . . . . . . . . . . . . .
225
Moisture Sensitivity (see Technical Brief TB363)
SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Level 1
SOT-23 Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Level 1
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
(Lead Tips Only)
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.
JA
is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
Electrical Specifications
V
SUPPLY
=
5V, A
V
= +1, R
F
= 510
, R
L
= 100
, Unless Otherwise Specified
PARAMETER
TEST CONDITIONS
(NOTE 2)
TEST
LEVEL
TEMP.
(
o
C)
HFA1155IB (SOIC)
HFA1155IH (SOT-23)
UNITS
MIN
TYP
MAX
MIN
TYP
MAX
INPUT CHARACTERISTICS
Input Offset Voltage (Note 3)
A
25
-
2
6
-
2
6
mV
A
Full
-
-
10
-
-
10
mV
Input Offset Voltage Drift
C
Full
-
10
-
-
10
-
V/
o
C
V
IO
CMRR
V
CM
=
2V
A
25
40
46
-
40
46
-
dB
A
Full
38
-
-
38
-
-
dB
V
IO
PSRR
V
S
=
1.25V
A
25
45
50
-
45
50
-
dB
A
Full
42
-
-
42
-
-
dB
Non-Inverting Input Bias Current (Note 3)
+IN = 0V
A
25
-
25
40
-
25
40
A
A
Full
-
-
65
-
-
65
A
+I
BIAS
Drift
C
Full
-
40
-
-
40
-
nA/
o
C
+I
BIAS
CMS
V
CM
=
2V
A
25
-
20
40
-
20
40
A/V
A
Full
-
-
50
-
-
50
A/V
Inverting Input Bias Current (Note 3)
-IN = 0V
A
25
-
12
50
-
12
50
A
A
Full
-
-
60
-
-
60
A
-I
BIAS
Drift
C
Full
-
40
-
-
40
-
nA/
o
C
-I
BIAS
CMS
V
CM
=
2V
A
25
-
1
7
-
1
7
A/V
A
Full
-
-
10
-
-
10
A/V
-I
BIAS
PSS
V
S
=
1.25V
A
25
-
6
15
-
6
15
A/V
A
Full
-
-
27
-
-
27
A/V
Non-Inverting Input Resistance
A
25
25
50
-
25
50
-
k
Inverting Input Resistance
C
25
-
40
-
-
40
-
Input Capacitance (Either Input)
B
25
-
2
-
-
2
-
pF
Input Common Mode Range
C
Full
2.5
3.0
-
2.5
3.0
-
V
Input Noise Voltage (Note 3)
100kHz
B
25
-
4.7
-
-
4.7
-
nV/
Hz
+Input Noise Current (Note 3)
100kHz
B
25
-
26
-
-
26
-
pA/
Hz
-Input Noise Current (Note 3)
100kHz
B
25
-
35
-
-
35
-
pA/
Hz
TRANSFER CHARACTERISTICS
Open Loop Transimpedance Gain (Note 3)
B
25
-
630
-
-
630
-
k
Minimum Stable Gain
A
Full
1
-
-
1
-
-
V/V
HFA1155
3
AC CHARACTERISTICS
A
V
= +2, (Note 4) Unless Otherwise Specified
-3dB Bandwidth
(V
OUT
= 0.2V
P-P
, Note 3)
A
V
= -1
B
25
-
370
-
-
360
-
MHz
A
V
= +1
B
25
-
370
-
-
365
-
MHz
A
V
= +2
B
25
-
380
-
-
355
-
MHz
-3dB Bandwidth (V
OUT
= 2V
P-P
)
A
V
= +2
B
25
-
175
-
-
170
-
MHz
Gain Flatness
(V
OUT
= 0.2V
P-P
, Note 3)
To 25MHz
B
25
-
0.03
-
-
0.06
-
dB
To 50MHz
B
25
-
0.04
-
-
0.06
-
dB
To 100MHz
B
25
-
0.15
-
-
0.1
-
dB
Full Power Bandwidth
(V
OUT
= 5V
P-P
at A
V
= +2;
V
OUT
= 4V
P-P
at A
V
= +1, Note 3)
A
V
= +1
B
25
-
50
-
-
45
-
MHz
A
V
= +2
B
25
-
75
-
-
75
-
MHz
OUTPUT CHARACTERISTICS
A
V
= +2, (Note 4) Unless Otherwise Specified
Output Voltage
A
V
= -1
A
25
3.0
3.3
-
3.0
3.3
-
V
A
Full
2.5
3.0
-
2.5
3.0
-
V
Output Current
R
L
= 50
, A
V
= -1
A
25, 85
40
55
-
40
55
-
mA
A
-40
35
50
-
35
50
-
mA
DC Closed Loop Output Resistance (Note 3)
B
25
-
0.09
-
-
0.09
-
2nd Harmonic Distortion (Note 3)
10MHz, V
OUT
= 2V
P-P
B
25
-
-53
-
-
-53
-
dBc
20MHz, V
OUT
= 2V
P-P
B
25
-
-47
-
-
-47
-
dBc
3rd Harmonic Distortion (Note 3)
10MHz, V
OUT
= 2V
P-P
B
25
-
-66
-
-
-66
-
dBc
20MHz, V
OUT
= 2V
P-P
B
25
-
-60
-
-
-60
-
dBc
TRANSIENT CHARACTERISTICS
A
V
= +2, (Note 4) Unless Otherwise Specified
Rise and Fall Times
V
OUT
= 0.5V
P-P
B
25
-
1.1
-
-
1.1
-
ns
Overshoot
V
OUT
= 0.5V
P-P
B
25
-
12
-
-
11
-
%
Slew Rate
(V
OUT
= 5V
P-P
at A
V
= +2, -1;
V
OUT
= 4V
P-P
at A
V
= +1)
A
V
= -1
B
25
-
1700
-
-
1650
-
V/
s
A
V
= +1
B
25
-
290
-
-
270
-
V/
s
A
V
= +2
B
25
-
535
-
-
510
-
V/
s
Settling Time (V
OUT
= 2V to 0V, Note 3)
To 0.1%
B
25
-
30
-
-
38
-
ns
To 0.05%
B
25
-
40
-
-
50
-
ns
To 0.01%
B
25
-
70
-
-
75
-
ns
Overdrive Recovery Time
V
IN
=
2V
B
25
-
7
-
-
7
-
ns
VIDEO CHARACTERISTICS
A
V
= +2, (Note 4) Unless Otherwise Specified
Differential Gain
NTSC, R
L
= 150
B
25
-
0.02
-
-
0.02
-
%
NTSC, R
L
= 75
B
25
-
0.02
-
-
0.02
-
%
Differential Phase
NTSC, R
L
= 150
B
25
-
0.06
-
-
0.06
-
Degrees
NTSC, R
L
= 75
B
25
-
0.12
-
-
0.12
-
Degrees
POWER SUPPLY CHARACTERISTICS
Power Supply Range
Note 5
B
Full
2.25
-
5.5
2.25
-
5.5
V
Power Supply Current (Note 3)
A
Full
-
5.5
8
-
5.5
8
mA
NOTES:
2. Test Level: A. Production Tested; B. Typical or Guaranteed Limit Based on Characterization; C. Design Typical for Information Only.
3. See Typical Performance Curves for more information.
4. The feedback resistor value depends on closed loop gain and package type. See the "Optimum Feedback Resistor" table in the Application
Information section for values used for characterization.
5. The minimum supply voltage entry is a typical value.
Electrical Specifications
V
SUPPLY
=
5V, A
V
= +1, R
F
= 510
, R
L
= 100
, Unless Otherwise Specified (Continued)
PARAMETER
TEST CONDITIONS
(NOTE 2)
TEST
LEVEL
TEMP.
(
o
C)
HFA1155IB (SOIC)
HFA1155IH (SOT-23)
UNITS
MIN
TYP
MAX
MIN
TYP
MAX
HFA1155
4
Application Information
Relevant Application Notes
The following Application Notes pertain to the HFA1155:
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
AN9897-Operating the HFA1155 from 5V Single
Supply
These publications may be obtained from Intersil's web site
(www.intersil.com) or via our AnswerFax system.
Performance Differences Between Packages
The HFA1155 is a high frequency current feedback amplifier.
As such, it is sensitive to parasitic capacitances which
influence the amplifier's operation. The different parasitic
capacitances of the SOIC and SOT-23 packages yield
performance differences (notably bandwidth and bandwidth
related parameters) between the two devices - see Electrical
Specification tables for details.
Because of these performance differences, designers
should evaluate and breadboard with the same package
style to be used in production.
Note that some "Typical Performance Curves" have separate
graphs for each package type. Graphs not labeled with a
specific package type are applicable to both packages.
Optimum Feedback Resistor
The enclosed frequency response graphs detail the
performance of the HFA1155 in various gains. Although the
bandwidth dependency on A
CL
isn't as severe as that of a
voltage feedback amplifier, there is an appreciable decrease
in bandwidth at higher gains. This decrease can 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 the 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 HFA1155 is optimized for
R
F
= 715
/604
(SOIC/SOT-23), at a gain of +2. Decreasing
R
F
decreases stability, resulting in excessive peaking and
overshoot (Note: Capacitive feedback causes 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.
5V Single Supply Operation
This amplifier operates at single supply voltages down to
4.5V. The dramatic supply current reduction at this operating
condition (refer also to Figure 25) makes this op amp an
even better choice for low power 5V systems. Refer to
Application Note AN9897 for further information.
Driving Capacitive Loads
Capacitive loads, such as an A/D input, or an improperly
terminated transmission line will degrade the amplifier's
phase margin resulting in frequency response peaking and
possible oscillations. In most cases, the oscillation can be
avoided by placing a resistor (R
S
) in series with the output
prior to the capacitance.
Figure 1 details starting points for the selection of this
resistor. The points on the curve indicate the R
S
and C
L
combinations for the optimum bandwidth, stability, and
settling time, but experimental fine tuning is recommended.
Picking a point above or to the right of the curve yields an
overdamped response, while points below or left of the curve
indicate areas of underdamped performance.
R
S
and C
L
form a low pass network at the output, thus
limiting system bandwidth well below the amplifier bandwidth
of 380MHz/355MHz (SOIC/SOT-23, A
V
= +2). By decreasing
R
S
as C
L
increases (as illustrated by the curves), the
maximum bandwidth is obtained without sacrificing stability.
In spite of this, bandwidth still decreases as the load
capacitance increases. For example, at A
V
= +2, R
S
= 30
,
C
L
= 22pF, the SOIC bandwidth is 290MHz, but the
bandwidth drops to 90MHz at A
V
= +2, R
S
= 6
,
C
L
= 390pF.
OPTIMUM FEEDBACK RESISTOR
A
CL
R
F
(
)
SOIC/SOT-23
BANDWIDTH (MHz)
SOIC/SOT-23
-1
576/576
370/360
+1
453, (+R
S
= 348)/
453, (+R
S
= 221)
370/365
+2
715/604
380/355
+5
402/475
300/300
+10
182/182
230/250
HFA1155
5
PC Board Layout
The frequency response of this amplifier depends greatly on
the amount of care taken in designing the PC board. The
use of low inductance components such as chip
resistors and chip capacitors is strongly recommended,
while a solid ground plane is a must!
Attention should be given to decoupling the power supplies.
A large value (10
F) tantalum in parallel with a small value
chip (0.1
F) capacitor works well in most cases.
Terminated microstrip signal lines are recommended at the
input and output of the device. Output capacitance, such as
that resulting from an improperly terminated transmission
line, will degrade the frequency response of the amplifier
and may cause oscillations. In most cases, the oscillation
can be avoided by placing a resistor in series with the output.
Care must also be taken to minimize the capacitance to ground
seen by the amplifier's inverting input. The larger this
capacitance, the worse the gain peaking, resulting in pulse
overshoot and eventual instability. To reduce this capacitance,
remove the ground plane under traces connected to -IN and
keep these traces as short as possible.
Examples of good high frequency layouts are the evaluation
boards shown below.
Evaluation Boards
The performance of the HFA1155IB (SOIC) may be
evaluated using the HFA11XX Evaluation Board and a SOIC
to DIP adaptor like the Aries Electronics Part Number
08-350000-10. The SOT-23 version can be evaluated using
the OPAMPSOT23EVAL board.
Note that the feedback and gain setting resistors on both
boards must be changed to the appropriate values listed in
the "Optimum Feedback Resistor" table.
To order evaluation boards (part number HFA11XXEVAL or
OPAMPSOT23EVAL), please contact your local sales office.
The schematic and layout of the HFA11XXEVAL and
OPAMPSOT23EVAL boards are shown below.
HFA11XXEVAL TOP LAYOUT
HFA11XXEVAL BOTTOM LAYOUT
0
100
200
300
400
0
10
20
30
40
50
LOAD CAPACITANCE (pF)
SERIES OUTPUT RESIST
ANCE (
)
150
250
350
50
FIGURE 1. RECOMMENDED SERIES OUTPUT RESISTOR vs
LOAD CAPACITANCE
A
V
= +2
FIGURE 2. HFA11XXEVAL SCHEMATIC
1
2
3
4
8
7
6
5
+5V
10
F
0.1
F
NC
50
GND
GND
511
511
-5V
0.1
F
10
F
50
IN
OUT
NC
V
H
+IN
V
L
V+
GND
1
V-
HFA1155
PDF 
ZIP