Datasheet

OPA843
19
SBOS268C
www.ti.com
INPUT AND ESD PROTECTION
The OPA843 is built using a very high-speed complementary
bipolar process. The internal junction breakdown voltages are
relatively low for these very small geometry devices. These
breakdowns are reflected in the Absolute Maximum Ratings
table. All device pins are protected with internal ESD protec-
tion diodes to the power supplies, as shown in Figure 16.
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 (e.g., in systems with ±15V supply parts
driving into the OPA843), current-limiting series resistors
should be added into the two inputs. Keep these resistor
values as low as possible since high values degrade both
noise performance and frequency response. Figure 17 shows
one example of an overdrive protection circuit added to a
G = +5V/V design.
External
Pin
Internal
Cicuitry
+V
CC
–V
CC
OPA843
+5V
–5V
50Ω
50Ω
Power-supply
decoupling not shown.
125Ω
D1 D2
R
G
126Ω
50Ω
R
F
505Ω
V
O
D1 = D2 IN5911 (or equivalent)
50Ω Source
FIGURE 17. Gain of +5 with Input Protection.
FIGURE 16. Internal ESD Protection.