LT6375IDF#PBF datasheet(21/32 Pages) AD

21 / 32 page

LT6375

6375fa

For more information www.linear.com/LT6375

APPLICATIONS INFORMATION

Assuming a thermal resistance of 43°C/W, the die tem-

perature will experience a 34°C rise above ambient. This

impliesthatthemaximumambienttemperaturetheLT6375

should operate under the above conditions is:

TA =150°C – 34°C = 116°C

Keep in mind that the DFN package has an exposed pad

which can be used to lower the

θJA of the package. The

more PCB metal connected to the exposed pad, the lower

the thermal resistance.

The MSOP package has no exposed pad and a higher

thermal resistance (

θJA = 130°C/W). It should not be used

in applications which have a high ambient temperature,

require driving a heavy load, or require an extreme input

voltage.

THERMAL SHUTDOWN

For safety, the LT6375 will enter shutdown mode when

the die temperature rises to approximately 163°C. This

thermal shutdown has approximately 9°C of hysteresis

requiring the die temperature to cool 9°C before enabling

the amplifier again.

USE AT OTHER PRECISION DC GAINS

The array of resistors within the LT6375 provides numer-

ous configurable connections that provide precision gains

other than the unity differential gain options described

previously. Note that only the +IN and –IN pins can oper-

ate outside of the supply window. Since most of these

alternate configurations involve driving the REFx pins, as

well as the +IN and –IN pins, the input signals must be

less than the supply voltages. Fully differential gains are

available as shown in Table 9, and may be output-shifted

with a REF offset signal. These configurations allow the

LT6375 to be used as a versatile precision gain block with

essentially no external components besides the supply

decoupling. In most cases, only a single positive supply

will be required. In Table 9, connections are identified as

NC (no connect), INPUT (refers to both inputs driven,

+signalto+pins,–signalto–pins),CROSS(referstoinputs

cross-coupled, +signal to –pins, –signal to +pins), OUT

(refers to the output fed back to –pins), or REF (refers to

connectingtheREFpinto+pins).Thesameconfigurations

provide inverting gains by grounding any pins intended

for the +signal source. The differential input resistance is

also tabulated as well as the amplification factor of the

internal gain section involved (noise-gain, which helps to

estimate the error-budget of the configuration).

Single-ended noninverting gains are also available as

shown in Table 10, including many that operate as buffers

(loaded only by the op amp input bias). A rich option set

exists by using the REF pin as an additional variable. Two

attenuation options exist that can accept signals outside

the power supply range since they only drive the +IN pin.

In Table 10, connections are identified as NC (no connect),

INPUT (driven by the input), OUT (fed back from the

output), or GROUND (grounded). Table 10 also includes

tabulations of the internal resistor divider (DIV), noise

gain (re-amplification), and the input loading presented

by the circuit.

USE AS PRECISION AC GAIN BLOCK

In AC-coupled applications operating from a single power

supply, it is useful to set the output voltage at mid-supply

to maximize dynamic range. The LT6375 readily supports

this with no additional biasing components by connecting

specific pins to the V+ and V– potentials and AC-coupling

the signal paths. Table 11 shows the available inverting

gains and also tabulates the load resistances presented at

the input. In Table 11, connections are identified as NC (no

connect), AC IN (AC-coupled to the input) OUT (fed back

from the output), tied to V+, tied to V–, or AC GND (AC-

grounded). All pins that require an AC ground can share

a single bypass capacitor. Likewise, all pins driven from

the source signal may share a coupling capacitor as well.

The output should also connect to the load circuitry using

a coupling capacitor to block the mid-supply DC voltage.

The LT6375 may also be used for single-supply nonin-

verting AC gains by employing a combination of input

attenuation and re-amplification. With numerous choices

ofattenuationandre-amplification,severalhundredoverall

gain combinations are possible, ranging from 0.167 to 23.

ThecombinationsaremoreplentifulthantheDCconfigura-

tions because there is no constraint on matching internal

source resistances to minimize offset.

LT6375IDF#PBF Datasheet(PDF) 21 Page - Analog Devices

LT6375IDF#PBF Datasheet(HTML) 21 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Datasheet Download

Link URL