EL5444CSZ datasheet(16/24 Pages) RENESAS

16 / 24 page

EL5144, EL5146, EL5244, EL5246, EL5444

FN7177 Rev 2.00

Page 16 of 24

March 31, 2011

Description of Operation and Applications

Information

Product Description

The EL5144 series is a family of wide bandwidth, single

supply, low power, rail-to-rail output, voltage feedback

operational amplifiers. The family includes single, dual, and

quad configurations. The singles and duals are available

with a power-down pin to reduce power to 2.6µA typically. All

the amplifiers are internally compensated for closed loop

feedback gains of +1 or greater. Larger gains are acceptable

but bandwidth will be reduced according to the familiar Gain

Bandwidth Product.

Connected in voltage follower mode and driving a high

impedance load, the EL5144 series has a -3dB bandwidth of

100MHz. Driving a 150

 load, they have a -3dB bandwidth

of 60MHz while maintaining a 200V/µs slew rate. The input

common mode voltage range includes ground while the

output can swing rail-to-rail.

Power Supply Bypassing and Printed Circuit

Board Layout

As with any high-frequency device, good printed circuit

board layout is necessary for optimum performance. Ground

plane construction is highly recommended. Lead lengths

should be as short as possible. The power supply pin must

be well bypassed to reduce the risk of oscillation For normal

single supply operation, where the GND pin is connected to

the ground plane, a single 4.7µF tantalum capacitor in

parallel with a 0.1µF ceramic capacitor from VS to GND will

suffice. This same capacitor combination should be placed

at each supply pin to ground if split supplies are to be used.

In this case, the GND pin becomes the negative supply rail.

For good AC performance, parasitic capacitance should be

kept to a minimum. Use of wire wound resistors should be

avoided because of their additional series inductance. Use

of sockets, particularly for the SO package, should be

avoided if possible. Sockets add parasitic inductance and

capacitance that can result in compromised performance.

Input, Output and Supply Voltage Range

The EL5144 series has been designed to operate with a

single supply voltage of 5V. Split supplies can be used so

long as their total range is 5V.

The amplifiers have an input common mode voltage range

that includes the negative supply (GND pin) and extends to

within 1.5V of the positive supply (VS pin). They are

specified over this range.

The output of the EL5144 series amplifiers can swing rail to

rail. As the load resistance becomes lower in value, the

ability to drive close to each rail is reduced. However, even

with an effective 150

 load resistor connected to a voltage

halfway between the supply rails, the output will swing to

within 150mV of either rail.

Figure 48 shows the output of the EL5144 series amplifier

swinging rail to rail with RF = 1k, AV = +2 and RL = 1M.

Figure 49 is with RL = 150

CEA

Enable Amplifier A

(Enabled when high)

(Reference Circuit 3)

CEB

Enable Amplifier B

(Enabled when high)

(Reference Circuit 3)

1, 5

2, 6,

10, 12

No Connect.

Not internally

connected.

Pin Descriptions (Continued)

EL5144

5 Ld

SOT23

EL5146

8 Ld

SO/PDIP

EL5244

8 Ld SO/

PDIP/MSOP

EL5246

10 Ld

MSOP

EL5246

14 Ld

SO/PDIP

EL5444

14 Ld

SO/PDIP

EL5444

16 Ld

QSOP NAME

FUNCTION

EQUIVALENT CIRCUIT

FIGURE 48.

FIGURE 49.

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