current limit behavior. The inputs are protected even if no
power supply voltage is present.
The output sense connection can be used to sense the output
voltage directly at the load for best accuracy. Figure 5 shows
how to drive a load through series interconnection resis-
tance. Remotely located feedback paths may cause instabil-
ity. This can be generally be eliminated with a high
frequency feedback path through C1. Heavy loads or long
lines can be driven by connecting a buffer inside the feed-
back path (Figure 6).
OUTPUT VOLTAGE SENSE (SOL-16 package only)
The surface-mount version of the INA114 has a separate
output sense feedback connection (pin 12). Pin 12 must be
connected to the output terminal (pin 11) for proper opera-
tion. (This connection is made internally on the DIP version
of the INA114.)
V+
G • VD
2
VCM
–
INA114
Over-Voltage
Protection
A1
25kΩ
25kΩ
VD
50kΩ
RG
G = 1 +
2
25kΩ
25kΩ
A3
V
O = G • VD
RG
VD
2
A2
Over-Voltage
Protection
25kΩ
25kΩ
VCM
G • VD
2
VCM
+
V–
FIGURE 4. Voltage Swing of A1 and A2.
Surface-mount package
version only.
Surface-mount package
version only.
Output
Sense
VI–N
VI–N
C1
1000pF
Output
Sense
OPA633
RG
IL: ±100mA
RL
INA114
RG
INA114
180Ω
VI+N
Ref
Ref
VI+N
Load
Equal resistance here preserves
good common-mode rejection.
FIGURE 5. Remote Load and Ground Sensing.
FIGURE 6. Buffered Output for Heavy Loads.
VI–N
VI+N
VO
22.1kΩ
22.1kΩ
511Ω
INA114
Ref
Shield is driven at the
common-mode potential.
100Ω
For G = 100
RG = 511Ω // 2(22.1kΩ)
effective RG = 505Ω
OPA602
FIGURE 7. Shield Driver Circuit.
®
10
INA114
BB [ BURR-BROWN CORPORATION ]
