LTC6085CDHC datasheet(11/16 Pages) LINEAR

11 / 16 page

LTC6084/LTC6085

60845fa

APPLICATIONS INFORMATION

Figure 3. Inverting Ampliﬁer with Muxed Output

–

10k

OUT

LTC6084

(DD PACKAGE)

SEL = 5V, OUT = –INA

SEL = 0V, OUT = –INB

10k

SHDN

FAIRCHILD

NC7SZ04 OR

EQUIVALENT

INA

10k

60845 F03

INB

SEL

–

SHDN Pins

Pins 5 and 6 are used for power shutdown of the LTC6084

in the DD package. If they are ﬂoating, internal current

sources pull pins 5 and 6 to V+ and the ampliﬁers operate

normally. In shutdown the ampliﬁer output is high imped-

ance, and each ampliﬁer draws less than 1μA current.

This feature allows the part to be used in muxed output

applications as shown in Figure 3.

ESD

The LTC6084/LTC6085 has reverse-biased ESD protection

diodes on all inputs and outputs as shown in the Simpli-

ﬁed Schematic. If these pins are forced beyond either

supply, unlimited current will ﬂow through these diodes.

If the current is transient and limited to 100mA or less,

no damage to the device will occur.

The ampliﬁer input bias current is the leakage current of

these ESD diodes. This leakage is a function of the tem-

perature and common mode voltage of the ampliﬁer, as

shown in the Typical Performance Characteristics.

Noise

In the frequency region above 1kHz, the LTC6084/LTC6085

shows good noise voltage performance. In this region,

noise can be dominated by the total source resistance of the

particular application. Speciﬁcally, these ampliﬁers exhibit

the noise of a 58k resistor, meaning it is desirable to keep

the source and feedback resistance at or below this value,

i.e., RS + RG||RFB ≤ 58k. Above this total source impedance,

the noise voltage is dominated by the resistors.

At low frequency, noise current can be estimated from the

expression in = √2qIB, where q = 1.6 • 10–19 coulombs.

Equating √4kTR

Δf and R√2qIBΔf shows that for a source

resistor below 50GΩ the ampliﬁer noise is dominated by

the source resistance. Noise current rises with frequency.

See the curve Input Noise Current vs Frequency in the

Typical Performance Characteristics section.

LTC6085CDHC датащи(PDF) 11 Page - Linear Integrated Systems

LTC6085CDHC датащи(HTML) 11 Page - Linear Integrated Systems

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

датащи скачать

ссылки URL