EL5123, EL5223, EL5323, EL5423

FN7176 Rev 3.00

Page 12 of 17

August 31, 2010

Applications Information

Product Description

The EL5123, EL5223, EL5323, and EL5423 unity gain buffers

are fabricated using a high voltage CMOS process. It exhibits

rail-to-rail input and output capability and has low power

consumption (600µA per buffer). These features make the

EL5123, EL5223, EL5323, and EL5423 ideal for a wide range

of general-purpose applications. When driving a load of 10k



and 12pF, the EL5123, EL5223, EL5323, and EL5423 have a -

3dB bandwidth of 12MHz and exhibits 15V/µs slew rate.

Operating Voltage, Input, and Output

The EL5123, EL5223, EL5323, and EL5423 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 EL5123,

EL5223, EL5323, and EL5423 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” on

page 8.

The output swings of the EL5123, EL5223, EL5323, and

EL5423 typically extend to within 50mV 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 24 shows the input and output waveforms for the

device. Operation is from ±5V supply with a 10k

load

FIGURE 24. OPERATION WITH RAIL-TO-RAIL INPUT AND

OUTPUT

Short Circuit Current Limit

The EL5123, EL5223, EL5323, and EL5423 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

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

±30mA. This limit is set by the design of the internal metal

interconnects.

Output Phase Reversal

The EL5123, EL5223, EL5323, and EL5423 are immune to

the device with the input voltage driven beyond the supply

rails. Although the device's output will not change phase, the

input's over-voltage 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.

FIGURE 25. OPERATION WITH BEYOND-THE-RAILS INPUT

Power Dissipation

With the high-output drive capability of the EL5123, EL5223,

EL5323, and EL5423 buffer, 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

buffer to remain in the safe operating area.

The maximum power dissipation allowed in a package is

determined according to Equation 1:

where:

The maximum power dissipation actually produced by an IC is

the total quiescent supply current times the total power supply

voltage, plus the power in the IC due to the loads, or:

5V

5V

10µs

1V

1V

10µs

–



---------------------------------------------

=

(EQ. 1)

iV



S





–

+



=

(EQ. 2)