71M6103 Maxim, 71M6103 Datasheet - Page 6

• Manufacturer Part Number: 71M6103
• Description: The 71M6103/71M6113/71M6201/71M6203/71M6601/71M6603 (71M6xxx) isolated sensor ICs enable Teridian's 4th-generation polyphase-metering 71M654x systems-on-chips (SoCs) to use nonisolating sensors such as resistive shunts without the need for costly and
• Manufacturer: Maxim

consideration that applies to the resistance range of the shunt.
Current Sensor Side
PDS_6xxx_010
The shunt resistance must be balanced with the maximum current range of the part type, as shown in
Table
shunt resistance for a given current has to be chosen carefully as not to exceed the maximum RMS
voltage at the INP/INN pins of the 71M6xxx. The maximum wattage of the shunt resistor is another
The inputs of the preamplifier are referenced to local ground (the GND pin of the 71M6xxx). This means
that in an isolated system, the INP and INN pins have to be biased towards this local GND. See
3.2
3.2.1 Current Sensor Side
Figure 2
following components:
3.2.2 Pulse Transformer
A low-cost pulse transformer is used for the link between the 71M654x and the 71M6xxx. It is the
responsibility of the meter system designer to qualify the transformer used in the system over the required
operating temperature range. The following commercially available transformer is suitable for this
application:
v1.2
71M6601
71M6603
71M6103
71M6113
71M6201
71M6203
Note 1: S = single phase, P = polyphase.
Note 2: Accuracy over temperature (-40°C to +85°C for 71M620x parts, -20°C to +60° for all other parts), when combined with
71M654x or 71M654xH IC.
Note 3: Maximum resistance at maximum current.
Note 4: Power at maximum current and typical shunt resistance.
Note 5: Typical resistance values provide room for overhead while maintaining optimum dynamic range.
Part
•
•
•
•
2. Various combinations of current ranges and shunt resistance values are possible. However, the
External Components for the 71M6xxx
1.0µF capacitor between the GND and VCC pins. This capacitor minimizes the VCC ripple
voltage.
One 1kΩ resistor each from the sensor output pins to GND. These resistors help to bias the input
voltage at the INP and INN pins towards GND.
In environments where EMC is a concern, ferrite beads can be placed between the sense pins of
the shunt resistor and the INP/INN pins of the 71M6xxx.
Würth Electronics Midcom Inc., P/N 750-11-0056 REV 2 (www.midcom-inc.com)
shows the external components required for the 71M6xxx. It is recommended to use the
Application
S
P
P
S
P
for details.
1
Maximum
Current
100
200
(A)
© 2008–2011 Teridian Semiconductor Corporation
60
Table 2: Product Variations
Accuracy
Class
(%)
0.5
0.2
0.2
1
1
1
2
Voltage at
Maximum
INP/INN
RMS
(mV)
19.6
12.6
44
Resistance
Maximum
Shunt
(µΩ)
736
196
63
3
Power
Shunt
1.44
71M6xxx Data Sheet
(W)
1.2
2.0
4
Resistance
Typical
Shunt
(µΩ)
400
120
50
3.2.1
5
6