AS1702 datasheet(14/20 Pages) AMSCO

14 / 20 page

www.austriamicrosystems.com

Revision 1.47

14 - 20

AS1702 - AS1705

Data Sheet - Ap p lica tio n In fo r m a tio n

If the internal power dissipation exceeds the maximum allowed for a given package, power dissipation should be

reduced by increasing the ground plane heat-sinking capabilities and increasing the size of the device traces (see Lay-

out and Grounding Considerations on page 15). Additionally, reducing VCC, increasing load impedance, and decreas-

ing ambient temperature can reduce device power dissipation.

The integrated thermal-overload protection circuitry limits the total device power dissipation. Note that if the junction

temperature is

≥ +145ºC, the integrated thermal-overload protection circuitry will disable the amplifier output stage. If

the junction temperature is reduced by 9°, the amplifiers will be re-enabled.

Note:

A pulsing output under continuous thermal overload results as the device heats and cools.

Fixed Differential Gain (AS1703, AS1704, and AS1705)

The AS1703, AS1704, and AS1705 contain different internally-fixed gains (see Ordering Information on page 19). A

fixed gain facilitates simplified designs, decreased footprint size, and elimination of external gain-setting resistors.

The fixed gain values are achieved using resistors R1 and R2 (see Figure 31 on page 12).

Adjustable Differential Gain (AS1702)

Gain-Setting Resistors

The AS1702 uses external feedback resistors, RF and RIN (Figure 33), to set the gain of the device as:

where AV is the desired voltage gain. For example, RIN = 10k

Ω, RF = 20kΩ yields a gain of 2V/V, or 6dB.

Note:

RF can be either fixed or variable, allowing the gain to be controlled by software (using a AS150x digital poten-

tiometer. For more information on the AS1500 family of digital potentiometers, refer to the latest version of the

AS150x data sheet, available from the austriamicrosystems website http://www.austriamicrosystems.com.)

Figure 33. Setting the AS1702 Gain

AV =

RIN

(EQ 7)

AS1702

–

20k

Bias

Generator

Inverting

Differential Input

Non-Inverting

Differential Input

CIN*

10µF

CIN*

10µF

RIN

10k

RIN

10k

* Optional

CBIAS

0.1µF

OUT+

IN-

OUT-

IN+

BIAS

AS1702 数据表(PDF) 14 Page - ams AG

AS1702 数据表(HTML) 14 Page - ams AG

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

数据表下载