OPA628 Burr-Brown, OPA628 Datasheet - Page 11

• Manufacturer Part Number: OPA628
• Description: Low Distortion Wideband OPERATIONAL AMPLIFIER
• Manufacturer: Burr-Brown

FIGURE 5. Settling Time Test Circuit.
Note that the short circuit condition represents the maximum
amount of internal power dissipation that can be generated.
Thus, the “Maximum Power Dissipation” curve starts at
1.2W and is derated based on a 175 C maximum junction
temperature and the junction-to-ambient thermal resistance,
with temperature is shown in Figure 7.
FIGURE 6. Maximum Power Dissipation.
FIGURE 7. Short Circuit Current vs Temperature.
JA
, of the package. The variation of short circuit current
200
180
160
140
120
100
1.2
1.0
0.8
0.6
0.4
0.2
–50
0
0
50
–25
+25
Sink
0
Ambient Temperature (°C)
+50
Temperature (°C)
25
a
R
1
+75
R
R
50
2
1
+100
c
75
50
Source
+125
100
OPA628
G = –n
nR
nR
2V
2
1
125
+150
n+1
11
b
1
of settling response at b
INPUT PROTECTION
Static damage has been well recognized for MOSFET de-
vices, but any semiconductor device deserves protection
from this potentially damaging source. The OPA628 incor-
porates on-chip ESD protection diodes as shown in Figure 8.
This eliminates the need for the user to add external protec-
tion diodes, which can add capacitance and degrade AC
performance.
FIGURE 8. Internal ESD Protection.
All pins on the OPA628 are internally protected from ESD
by means of a pair of back-to-back reverse-biased diodes to
either power supply as shown. These diodes will begin to
conduct when the input voltage exceeds either power supply
by about 0.7V. This situation can occur with loss of the
amplifier’s power supplies while a signal source is still
present. The diodes can typically withstand a continuous
current of 30mA without destruction. To insure long term
reliability, however, diode current should be externally lim-
ited to approximately 10mA whenever possible.
OFFSET VOLTAGE ADJUSTMENT
The OPA628’s input offset voltage is laser-trimmed and will
require no further adjustment for most applications. How-
ever, if additional adjustment is needed, the circuit in Figure
9 can be used without degrading offset drift with tempera-
ture. Avoid external adjustment whenever possible since
extraneous noise, such as power supply noise, can be inad-
vertently coupled into the amplifier’s inverting input termi-
nal. Remember that additional offset errors can be created by
External
Pin
R
3
OPA620
G = n+1
nR
3
+V
–V
CC
CC
50
OPA628
1M
Tektronix11402
15pF
Internal
Circuitry
®