el2001acn Intersil Corporation, el2001acn Datasheet - Page 5

• Manufacturer Part Number: el2001acn
• Description: Low Power, 70mhz Buffer Amplifier
• Manufacturer: Intersil Corporation

Typical Performance Curves
Burn-In Circuit
Simplified Schematic
Small Signal Response
Large Signal Response
5
(Continued)
EL2001
Application Information
The EL2001 is a monolithic buffer amplifier built on Elantec's
proprietary dielectric isolation process that produces NPN
and PNP transistors with essentially identical DC and AC
characteristics. The EL2001 takes full advantage of the
complementary process with a unique circuit topology.
Elantec has applied for two patents based on the EL2001’s
topology. The patents relate to the base drive and feedback
mechanism in the buffer. This feedback makes 2000V/µs
slew rates with 100: loads possible with very low supply
current.
Power Supplies
The EL2001 may be operated with single or split supplies
with total voltage difference between 10V (±5V) and 36V
(±18V). It is not necessary to use equal split value supplies.
For example -5V and +12V would be excellent for signals
from -2V to +9V.
Bypass capacitors from each supply pin to ground are highly
recommended to reduce supply ringing and the interference
it can cause. At a minimum, 1µF tantalum capacitor with
short pins should be used for both supplies.
Input Characteristics
The input to the EL2001 looks like a resistance in parallel
with about 3.5pF in addition to a DC bias current. The DC
bias current is due to the miss-match in beta and collector
current between the NPN and PNP transistors connected to
the input pin. The bias current can be either positive or
negative. The change in input current with input voltage
(R
boost. R
input range; typical input current curves are shown in the
characteristic curves. Internal clamp diodes from the input to
the output are provided. These diodes protect the transistor
base emitter junctions and limit the boost current during slew
to avoid saturation of internal transistors. The diodes begin
conduction at about ±2.5V input to output differential. When
that happens the input resistance drops dramatically. The
diodes are rated at 50mA. When conducting they have a
series resistance of about 20:. There is also 100: in series
with the input that limits input current. Above ±7.5V
differential input to output, additional series resistance
should be added.
Source Impedance
The EL2001 has good input to output isolation. When the
buffer is not used in a feedback loop, capactive and resistive
sources up to 1Mb present no oscillation problems. Care
must be used in board layout to minimize output to input
coupling. CAUTION: When using high source impedances
(R
output offset, load resistor, and the action of the boost circuit.
See typical performance curves.
IN
S
> 100k:), significant gain errors can be observed due to
) is affected by the output load, beta and the internal
IN
can actually appear negative over portions of the