am411 ETC-unknow, am411 Datasheet - Page 4

• Manufacturer Part Number: am411
• Description: Voltage Transmitter Ic -circuits
• Manufacturer: ETC-unknow

VOLTAGE TRANSMITTER IC
FUNCTIONAL DESCRIPTION
The IC AM411 is an integrated voltage transmitter for bridge input signals. With variations of a few
external components the output voltage can be adjusted over a wide range. In addition to the resis-
tors R
input of the voltage output stage the AM411 can be used for single ended input signals as well.
Typical values for the external components are listed in the Application Notes.
Basically the AM411 consists of 3 functional blocks as they are shown in Figure 1:
1. A high accuracy instrumentation amplifier with an internal gain G
2. An operational amplifier output stage used for voltage transmission and as the voltage output.
3. A voltage reference can be used as an excitation for constant voltage sensors or as supply for
The transfer function for the output voltage of the instrumentation amplifier is:
with the offset voltage V
the IC is valid
with the adjustable gain G
The minimum supply voltage, which has to be adjusted, can be calculated over
analog microelectronics
the bias voltage (pin ZA) for differential input signals.
The output stage has an output current limitation protecting the IC.
other external devices.
1
and R
2
the circuitry needs only one external capacitor C
V
V
V
G
S
OUTIA
OUT
OP
≥ V
=
=
OUTmax
=
R
R
G
ZA
1
2
G
OP
OP
+
IA
which can be adjusted on pin ZA. For die entire output voltage V
1
⋅
V
V
+ 5V
IN
INOP
+
V
ZA
1
for a basic application. Using the
IA
and the possibility to adjust
AM411
April 99
OUT
4/6
of