Datasheet

External

-V

Internal

Circuitry

OPA890

SBOS369B –MAY 2007–REVISED DECEMBER 2009

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series-terminated at the source end only. Treat INPUT AND ESD PROTECTION

the trace as a capacitive load in this case, and

The OPA890 is built using a very high-speed,

set the series resistor value as shown in the plot

complementary, bipolar process. The internal junction

of Recommended R

vs Capacitive Load. This

breakdown voltages are relatively low for these very

configuration does not preserve signal integrity as

small geometry devices. These breakdowns are

well as a doubly-terminated line. If the input

reflected in the Absolute Maximum Ratings table. All

impedance of the destination device is low, there

device pins are protected with internal ESD protection

will be some signal attenuation because of the

diodes to the power supplies, as shown in Figure 55.

voltage divider formed by the series output into

the terminating impedance.

e. Socketing a high-speed part such as the

OPA890 is not recommended. The additional

lead length and pin-to-pin capacitance introduced

by the socket can create an extremely

troublesome parasitic network that can make it

almost impossible to achieve a smooth, stable

frequency response. Best results are obtained by

soldering the OPA890 directly onto the board.

Figure 55. Internal ESD Protection

These diodes provide moderate protection to input

overdrive voltages above the supplies as well. The

protection diodes can typically support 30mA

continuous current. Where higher currents are

possible (for example, in systems with ±15V supply

parts driving into the OPA890), current-limiting series

resistors should be added into the two inputs. Keep

these resistor values as low as possible, because

high values degrade both noise performance and

frequency response.

Product Folder Link(s): OPA890