HFA1113IBZ Intersil, HFA1113IBZ Datasheet - Page 7

• Manufacturer Part Number: HFA1113IBZ
• Description: IC BUFFER 850MHZ 8-SOIC
• Manufacturer: Intersil

Specifications of HFA1113IBZ

• Amplifier Type: Buffer
• Number Of Circuits: 1
• Slew Rate: 2400 V/µs
• -3db Bandwidth: 850MHz
• Current - Input Bias: 25µA
• Voltage - Input Offset: 8000µV
• Current - Supply: 21mA
• Current - Output / Channel: 60mA
• Voltage - Supply, Single/dual (±): 9 V ~ 11 V, ±4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Rohs Compliant: YES
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• Gain Bandwidth Product: -

Clamp Accuracy
The clamped output voltage will not be exactly equal to the
voltage applied to V
mismatches, necessitate a clamp accuracy parameter which
is found in the device specifications. Clamp accuracy is a
function of the clamping conditions. Referring again to
Figure 4, it can be seen that one component of clamp
accuracy is the VBE mismatch between the Q
and the Q
same current level there would be no V
contribution to the inaccuracy. The Q
biased at a constant current, but as described earlier, the
current through Q
as I
increase as well. I
(A
as the overdrive increases. As an example, the specified
accuracy of ±100mV (A
degrades to ±240mV for a 3X (200%) overdrive, as shown in
Figure 43.
Consideration must also be given to the fact that the clamp
voltages have an affect on amplifier linearity. The
“Nonlinearity Near Clamp Voltage” curve, Figure 48,
illustrates the impact of several clamp levels on linearity.
Clamp Range
Unlike some competitor devices, both V
usable ranges that cross 0V. While V
than V
Typical Performance Curves
VCL
-100
-150
-200
200
150
100
CLAMP
-50
50
0
L
x V
FIGURE 5. SMALL SIGNAL PULSE RESPONSE
, both may be positive or negative, within the range
A
V
IN
X5
= +2
increases, causing the clamped output voltage to
- V
transistors. If the transistors always ran at the
OUT CLAMPED
X5
CLAMP
H
is equivalent to I
or V
V
= -1, V
is a function of the overdrive level
L
TIME (5ns/DIV.)
. Offset errors, mostly due to V
), so clamp accuracy degrades
7
H
= 1V) for a 1.6X overdrive
H
X6
CLAMP
must be more positive
BE
H
transistors are
and V
mismatch, and no
V
. V
SUPPLY
X6
BE
L
transistors,
have
increases
= ±5V, T
BE
HFA1113
A
= 25
o
C, R
restrictions indicated in the specifications. For example, the
HFA1113 could be limited to ECL output levels by setting
V
the same voltage (GND for instance) but the result won’t be
in a DC output voltage from an AC input signal. A
150mV - 200mV AC signal will still be present at the output.
Recovery from Overdrive
The output voltage remains at the clamp level as long as the
overdrive condition remains. When the input voltage drops
below the overdrive level (V
return to linear operation. A time delay, known as the
Overdrive Recovery Time, is required for this resumption of
linear operation. The plots of “Unclamped Performance” and
“Clamped Performance” (Figures 41 and 42) highlight the
HFA1113’s subnanosecond recovery time. The difference
between the unclamped and clamped propagation delays is
the overdrive recovery time. The appropriate propagation
delays are 8.0ns for the unclamped pulse, and 8.8ns for the
clamped (2X overdrive) pulse yielding an overdrive recovery
time of 800ps. The measurement uses the 90% point of the
output transition to ensure that linear operation has
resumed. Note: The propagation delay illustrated is
dominated by the fixturing. The delta shown is accurate, but
the true HFA1113 propagation delay is 500ps.
Overdrive recovery time is also a function of the overdrive
level. Figure 47 details the overdrive recovery time for
various clamp and overdrive levels.
L
H
= 100Ω, Unless Otherwise Specified
= -0.8V and V
-0.5
-1.0
-1.5
-2.0
2.0
1.5
1.0
0.5
0
FIGURE 6. LARGE SIGNAL PULSE RESPONSE
A
V
= +2
L
= -1.8V. V
TIME (5ns/DIV.)
CLAMP
H
and V
/A
VCL
L
may be connected to
) the amplifier will
July 11, 2005
FN1342.6