CLC5612IM datasheet(11/18 Pages) NSC

11 / 18 page

Typical Performance Characteristics (A

V = +2, RL= 100Ω,VS +5V

1,V

CM =VEE+(VS/2), RL tied to

VCM, unless specified) (Continued)

Application Division

CLC5612 Operation

The CLC5612 is a current feedback buffer fabricated in an

advanced complementary bipolar process. The CLC5612

operates from a single 5V supply or dual ±5V supplies.

Operating from a single 5V supply, the CLC5612 has the

following features:

•

Gains of +1, −1, and 2V/V are achievable without

external resistors

•

Provides 100mA of output current while consuming only

7.5mW of power

•

Offers low −79/−81dBc 2nd and 3rd harmonic distortion

•

Provides BW>50MHz and 1MHz distortion <−75dBc at

O =2VPP

The CLC5612 performance is further enhanced in ±5V

supply applications as indicated in the ±5V Electrical

Characteristics table and ±5V Typical Performance plots.

If gains other than +1, −1, or +2V/V are required, then the

CLC5602 can be used. The CLC5602 is a current feedback

amplifier with near identical performance and allows for

external feedback and gain setting resistors.

Current Feedback Amplifiers

Some of the key features of current feedback technology

are:

•

Independence of AC bandwidth and voltage gain

•

Inherently stable at unity gain

•

Adjustable frequency response with feedback resistor

•

High slew rate

•

Fast settling

Current feedback operation can be described using a simple

equation. The voltage gain for a non-inverting or inverting

current feedback amplifier is approximated by Equation 1.

Z(j )

(1)

where:

•

V is the closed loop DC voltage gain

•

f is the feedback resistor

•

Z(j

ω) is the CLC5612’s open loop transimpedance gain

•

Z(j

ω)/R

f is the loop gain

The denominator of Equation 1 is approximately equal to 1 at

low frequencies. Near the −3dB corner frequency in the

interaction between R

and Z(j

ω) dominates the circuit

performance. The value of the feedback resistor has a large

affect on the circuits performance. Increasing R

f has the

following affects:

•

Decreases loop gain

•

Decreases bandwidth

•

Reduces gain peaking

•

Lowers pulse response overshoot

•

Affects frequency response phase linearity

CLC5612 Design Information

Closed Loop Gain Selection

The CLC5612 is a current feedback op amp with R

f=Rg=1kΩ

on chip (in the package). Select from three closed loop gains

without using any external gain or feedback resistors.

Implement gains of +2, +1, and −1V/V by connecting pins 2

and 3 (or 5 and 6) as described in the chart below.

Gain A

Input Connections

Non-Inverting (pins 3,5)

Inverting (pins 2,6)

−1V/V

ground

input signal

+1V/V

input signal

NC (open)

+2V/V

input signal

ground

The gain accuracy of the CLC5612 is excellent and stable

over temperature change. The internal gain setting resistors,

and R

are diffused silicon resistors with a process

variation of ± 20% and a temperature coefficient of

−2000ppm/˚C. Although their absolute values change with

processing and temperature, their ratio (R

f/Rg)

remains

constant. If an external resistor is used in series with R

g, gain

accuracy over temperature will suffer.

Single Supply Operation (V

cc = +5V/V, VEE=GND)

The

specifications

given

the

±5V

Electrical

Characteristics table for single supply operation are

measured with a common mode voltage (V

cm) of 2.5V. Vcm is

the voltage around which the inputs are applied and the

output voltages are specified.

Pulse Crosstalk

Time (10ns/div)

Active Output

Channel

Inactive Output

Channel

DS015001-36

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