EL5221C
Dual 12MHz Rail-to-Rail Input-Output Buffer
Applications Information
Product Description
Short Circuit Current Limit
The EL5221C unity gain buffer is fabricated using a
high voltage CMOS process. It exhibits rail-to-rail input
and output capability and has low power consumption
(500µA per buffer). These features make the EL5221C
ideal for a wide range of general-purpose applications.
When driving a load of 10kΩ and 12pF, the EL5221C
has a -3dB bandwidth of 12MHz and exhibits 10V/µS
slew rate.
The EL5221C will limit the short circuit current to
120mA if the output is directly shorted to the positive
or the negative supply. If an output is shorted indefi-
nitely, the power dissipation could easily increase such
that the device may be damaged. Maximum reliability is
maintained if the output continuous current never
exceeds 30mA. This limit is set by the design of the
internal metal interconnects.
Operating Voltage, Input, and Output
Output Phase Reversal
The EL5221C is 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 EL5221C
specifications are stable over both the full supply range
and operating temperatures of -40°C to +85°C. Parame-
ter variations with operating voltage and/or temperature
are shown in the typical performance curves.
The EL5221C is immune to phase reversal as long as the
input voltage is limited from VS- -0.5V to VS+ +0.5V.
Figure 2 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 volt-
age 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.
The output swings of the EL5221C typically extend to
within 80mV 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 1 shows the input and output waveforms for
the device. Operation is from 5V supply with a 10kΩ
load connected to GND. The input is a 10VP-P sinusoid.
1V
10µS
The output voltage is approximately 9.985VP-P
.
V =±2.5V
S
T =25°C
A
V =6V
IN
P-P
5V
10µS
1V
V =±5V
S
T =25°C
A
V =10V
IN
P-P
Figure 2. Operation with Beyond-the-Rails
Input
Power Dissipation
5V
With the high-output drive capability of the EL5221C
buffer, it is possible to exceed the 125°C 'absolute-max-
imum junction temperature' under certain load current
conditions. Therefore, it is important to calculate the
maximum junction temperature for the application to
Figure 1. Operation with Rail-to-Rail Input and
Output
10
ELANTEC [ ELANTEC SEMICONDUCTOR ]
