OPA2990IDR datasheet(23/59 Pages) TI1

23 / 59 page

Input Low-Pass Filter

Ron_mux

Sn+1

Simplified Mux Model

RFILT

CFILT

Vn = 10 V

Vn+1 = ±10 V

10 V

±10 V

Buffer Amplifier

Idiode_transient

10 V

~±9.3 V

VIN+

VIN±

~0.7 V

VOUT

±10 V

Ron_mux

OPAx990

40 V

~0.7 V

VOUT

V+

Conventional Input Protection

Limits Differential Input Range

OPAx990 Provides Full 40-V

Differential Input Range

VIN+

VIN

VOUT

V+

VIN+

VIN

OPA990, OPA2990, OPA4990

www.ti.com

SBOS933D – FEBRUARY 2019 – REVISED JULY 2019

Product Folder Links: OPA990 OPA2990 OPA4990

Submit Documentation Feedback

7.3 Feature Description

7.3.1 Input Protection Circuitry

The OPAx990 uses a unique input architecture to eliminate the requirement for input protection diodes but still

provides robust input protection under transient conditions. Figure 48 shows conventional input diode protection

schemes that are activated by fast transient step responses and introduce signal distortion and settling time

delays because of alternate current paths, as shown in Figure 49. For low-gain circuits, these fast-ramping input

signals forward-bias back-to-back diodes, causing an increase in input current and resulting in extended settling

time.

Figure 48. OPAx990 Input Protection Does Not Limit Differential Input Capability

Figure 49. Back-to-Back Diodes Create Settling Issues

The OPAx990 family of operational amplifiers provides a true high-impedance differential input capability for high-

voltage applications using a patented input protection architecture that does not introduce additional signal

distortion or delayed settling time, making the device an optimal op amp for multichannel, high-switched, input

applications. The OPA990 tolerates a maximum differential swing (voltage between inverting and non-inverting

pins of the op amp) of up to 40 V, making the device suitable for use as a comparator or in applications with fast-

ramping input signals such as data-acquisition systems; see the TI TechNote MUX-Friendly Precision

Operational Amplifiers for more information.

OPA2990IDR Datasheet(PDF) 23 Page - Texas Instruments

OPA2990IDR Datasheet(HTML) 23 Page - Texas Instruments

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 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59

Datasheet Download

Link URL