6

LTC1063

CC

HARA TERISTICS

A

TYPICALPERFOR

CE

Transient Response

HORIZONTAL: 0.1ms/DIV, VERTICAL: 2V/DIV

SQUARE WAVE

1063 G16

PI FU CTIO S

Power Supply Pins (Pins 6, 3, N Package)

The positive and negative supply pin should be bypassed

with a high quality 0.1

µFceramiccapacitor.Inapplications

where the clock pin (5) is externally swept to provide

several cutoff frequencies, the output DC offset variation

is minimized by connecting an additional 1

µF solid tanta-

lum capacitor in parallel with the 0.1

µF disc ceramic. This

technique was used to generate the graphs of the output

DC offset variation versus clock; they are illustrated in the

Typical Performance Characteristics section.

When the power supply voltage exceeds

connect a signal diode between the positive supply pin and

ground to prevent latch-up (see Typical Applications).

Ground Pin (Pin 2, N Package)

The ground pin merges the internal analog and digital

ground paths. The potential of the ground pin is the

reference for the internal switched-capacitor resistors,

and the reference for the external clock. The positive input

of the internal op amp is also tied to the ground pin.

For dual supply operation, the ground pin should be

connected to a high quality AC and DC ground. A ground

plane, if possible, should be used. A poor ground will

degrade DC offset and it will increase clock feedthrough,

noise and distortion.

A small amount of AC current flows out of the ground pin

whether or not the internal oscillator is used. The fre-

quency of the ground current equals the frequency of the

internal or external clock. The average value of this current

is approximately 55

µA, 110µA, 170µA for ±2.5V, ±5V and

±7.5V supplies respectively.

For single supply operation, the ground pin should be

preferably biased at half supply (see Typical Applications).

of output DC offset voltage or to introduce a desired output

output pin equals two.

Any DC voltage applied to this pin will reflect at the output

pin of the filter multiplied by two.

pin is typically 10pA.

Pin 8 should always be connected to an AC ground; AC

signals applied to this pin will degrade the filter response.

Input Pin (Pin 1, N Package)

Pin 1 is the filter input and it is connected to an internal

switched-capacitor resistor. If the input pin is left floating,

the filter output will saturate. The DC input impedance of

pin 1 is very high; with

±5V supplies and 1MHz clock, the

DC input impedance is typically 1G

series, with the input pin will not alter the value of the