7

LT1224

S

APPLICATI

I FOR ATIO

Capacitive Loading

The LT1224 is stable with all capacitive loads. This is

accomplished by sensing the load induced output pole and

adding compensation at the amplifier gain node. As the

capacitive load increases, both the bandwidth and phase

margin decrease so there will be peaking in the frequency

domain and in the transient response. The photo of the

small-signal response with 1000pF load shows 50% peak-

ing. The large-signal response with a 10,000pF load shows

the output slew rate being limited by the short-circuit

current.

S

APPLICATI

TYPICAL

LT1224 • TA08

+

–

LT1224

R1

619

Ω

R3

825

Ω

C1

500pF

C2

100pF

R2

619

Ω

–38dB AT 10MHz

SMALL SIGNAL OVERSHOOT = 10%

Two Op Amp Instrumentation Amplifier

1MHz, 2nd Order Butterworth Filter

Cable Driving

LT1224 • TA07

R2

1k

+

–

IN

V

OUT

V

R1

1k

R3

75

Ω

R4

75

Ω

75

CABLE

Ω

LT1224

DAC Current-to-Voltage Converter

The wide bandwidth, high slew rate and fast settling time

of the LT1224 make it well-suited for current-to-voltage

conversion after current output D/A converters. A typical

application is shown on the first page of this data sheet

with a DAC-08 type converter with a full-scale output of

2mA. A compensation capacitor is used across the feed-

back resistor to null the pole at the inverting input caused

by the DAC output capacitance. The combination of the

LT1224 and DAC settles to 40mV in 140ns for both a 0V

to 10V step and for a 10V to 0V step.

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of circuits as described herein will not infringe on existing patent rights.

The LT1224 can drive coaxial cable directly, but for best

pulse fidelity the cable should be doubly terminated with

a resistor in series with the output.

LT1224 • TA06

LT1224 • TA09

+

–

LT1224

R3

1k

R5

220

Ω

1 +

+

+

= 102

TRIM R5 FOR GAIN

TRIM R1 FOR COMMON-MODE REJECTION

BW = 430kHz

+

–

LT1224

–

+

R2

1k

R1

10k

R4

10k

R4

1

2

R2

R1

(

R3

R2 + R3

R5

]