LT1795 datasheet(7/12 Pages) LINER

7 / 12 page

LT1795

APPLICATIO S I FOR ATIO

The LT1795 is a dual current feedback amplifier with high

output current drive capability. The amplifier is designed

to drive low impedance loads such as twisted-pair trans-

mission lines with excellent linearity.

SHUTDOWN/CURRENT SET

If the shutdown/current set feature is not used, connect

SHDN to V+ and SHDNREF to ground.

The SHDN and SHDNREF pins control the biasing of the

two amplifiers. The pins can be used to either turn off the

amplifiers completely, reducing the quiescent current to

less then 200

µA, or to control the quiescent current in

normal operation.

When VSHDN = VSHDNREF, the device is shut down. The

device will interface directly with 3V or 5V CMOS logic

when SHDNREF is grounded and the control signal is

applied to the SHDN pin. Switching time between the

active and shutdown states is about 1.5

µs.

Figures 1 to 4 illustrate how the SHDN and SHDNREF pins

can be used to reduce the amplifier quiescent current. In

both cases, an external resistor is used to set the current.

The two approaches are equivalent, however the required

resistor values are different. The quiescent current will be

approximately 115 times the current in the SHDN pin and

230 times the current in the SHDNREF pin. The voltage

across the resistor in either condition is V+ – 1.5V. For

example, a 50k resistor between V+ and SHDN will set the

Figure 1. RSHDN Connected Between V

+ and SHDN (Pin 10);

SHDNREF (Pin 11) = GND. See Figure 2

Figure 2. LT1795 Amplifier Supply Current vs RSHDN. RSHDN

Connected Between V+ and SHDN, SHDNREF = GND (See

Figure 1)

10 SHDN

RSHDN

V+

11 SHDNREF

1795 F01

RSHDN (kΩ)

75 100 125 150 175 200 225

1795 F02

TA = 25°C

VS = ±15V

Figure 4. LT1795 Amplifier Supply Current vs RSHDNREF.

RSHDNREF Connected Between SHDNREF and GND,

SHDN = V+ (See Figure 3)

RSHDNREF (kΩ)

50 100 150 200 250 300 350 400 450 500

1795 F04

TA = 25°C

VS = ±15V

Figure 3. RSHDNREF Connected Between SHDNREF (Pin 11)

and GND; SHDN (Pin 10) = V +. See Figure 4

10 SHDN

V+

11 SHDNREF

1795 F03

RSHDNREF

LT1795 датащи(PDF) 7 Page - Linear Technology

LT1795 датащи(HTML) 7 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12

датащи скачать

ссылки URL