11
FN7119.8
August 27, 2015
Applications Information
Product Description
The EL5111, EL5211, and EL5411 voltage feedback
amplifiers are fabricated using a high voltage CMOS
process. They exhibit rail-to-rail input and output capability,
are unity gain stable and have low power consumption
(2.5mA per amplifier). These features make the EL5111,
EL5211, and EL5411 ideal for a wide range of general-
purpose applications. Connected in voltage follower mode
and driving a load of 1k, the EL5111, EL5211, and EL5411
have a -3dB bandwidth of 60MHz while maintaining a 75V/µs
slew rate. The EL5111 is a single amplifier, the EL5211 a
dual amplifier, and the EL5411 a quad amplifier.
Operating Voltage, Input, and Output
The EL5111, EL5211, and EL5411 are specified with a single
nominal supply voltage from 5V to 15V or a split supply with
its total range from 5V to 15V. Correct operation is
guaranteed for a supply range of 4.5V to 16.5V. Most
EL5111, EL5211, and EL5411 specifications are stable over
both the full supply range and operating temperatures of
-40°C to +85°C. Parameter variations with operating voltage
and/or temperature are shown in the typical performance
curves.
The input common-mode voltage range of the EL5111,
EL5211, and EL5411 extends 500mV beyond the supply
rails. The output swings of the EL5111, EL5211, and EL5411
typically extend to within 100mV of positive and negative
supply rails with load currents of 5mA. Decreasing load
currents will extend the output voltage range even closer to
the supply rails. Figure 27 shows the input and output
waveforms for the device in the unity-gain configuration.
Operation is from ±5V supply with a 1k load connected to
GND. The input is a 10V
P-P
sinusoid. The output voltage is
approximately 9.8V
P-P
.
Short Circuit Current Limit
The EL5111, EL5211, and EL5411 will limit the short circuit
current to ±180mA if the output is directly shorted to the
positive or the negative supply. If an output is shorted
indefinitely, the power dissipation could easily increase such
that the device may be damaged. Maximum reliability is
maintained if the output continuous current never exceeds
±65mA. This limit is set by the design of the internal metal
interconnects.
Output Phase Reversal
The EL5111, EL5211, and EL5411 are immune to phase
reversal as long as the input voltage is limited from V
S
- -0.5V
to V
S
+ +0.5V. Figure 28 shows a photo of the output of the
device with the input voltage driven beyond the supply rails.
Although the device's output will not change phase, the
input's overvoltage should be avoided. If an input voltage
exceeds supply voltage by more than 0.6V, electrostatic
protection diodes placed in the input stage of the device
begin to conduct and overvoltage damage could occur.
Power Dissipation
With the high-output drive capability of the EL5111, EL5211,
and EL5411 amplifiers, it is possible to exceed the +125°C
'absolute-maximum junction temperature' under certain load
current conditions. Therefore, it is important to calculate the
maximum junction temperature for the application to
determine if load conditions need to be modified for the
amplifier to remain in the safe operating area.
The maximum power dissipation allowed in a package is
determined according to:
where:
•T
JMAX
= Maximum junction temperature
•T
AMAX
= Maximum ambient temperature
•
JA
= Thermal resistance of the package
•P
DMAX
= Maximum power dissipation in the package
OUTPUT INPUT
5V
5V 10µs
V
S
= ±5V, T
A
= +25°C, A
V
= 1, V
IN
= 10V
P-P
FIGURE 27. OPERATION WITH RAIL-TO-RAIL INPUT AND
OUTPUT
1V
1V 10µs
V
S
= ±2.5V, T
A
= +25°C, A
V
= 1, V
IN
= 6V
P-P
FIGURE 28. OPERATION WITH BEYOND-THE-RAILS INPUT
P
DMAX
T
JMAX
T
AMAX
–
JA
---------------------------------------------
=
(EQ. 1)
EL5111, EL5211, EL5411
