IXI848S1T/R IXYS, IXI848S1T/R Datasheet - Page 3

• Manufacturer Part Number: IXI848S1T/R
• Description: IC CURRENT MONITOR 0.7% 8SOIC
• Manufacturer: IXYS

Specifications of IXI848S1T/R

• Function: Current Monitor
• Sensing Method: High-Side
• Accuracy: ±0.7%
• Voltage - Input: 2.7 ~ 40 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC
• Product: Current Regulators
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Pin Description and Configuration
Detailed Circuit Description
The IXI848 is a precision high side current sense
monitor featuring an input voltage range of 2.7V to
40V, and a selectable ground referenced fixed
gain output of either 10 or 50.
A small voltage developed across an external
sense resistor (R
ground referenced voltage output at VOUT,
(Figure 1). The amplifier’s non-inverting input is
high impedance making the voltage at that
terminal equal to V
forces the high impedance inverting terminal to
equal the non-inverting input voltage by turning on
the P-Channel MOS FET.
As the P-Channel MOS FET is biased on by the
amplifier output, current is sourced through R
(10R or 10R+40R), to produce a voltage equal to
V
This develops a voltage across the inverting input
resistor, R that matches the sense voltage across
R
Consequently, the voltage at VOUT corresponds
to R
Output: VOUT = G [ (I
Gain:
Temperature coefficient:
R
The R
voltage across R
current to be monitored. Operating the IXI848 at or
near the full-scale sense voltage will minimize the
www.ixys.com
SOIC
IN
S
SENSE
, plus any associated input offset voltage, (V
1
2
3
4
5
6
7
8
– (I
G
(all on-chip resistors) R = 700ppm / °C typical
/ R.
SENSE
L
Component Selection
) (R
G = (R
R
IXYS
Name
VOUT
LOAD
G
GND
R10
R50
N/C
N/C
IN
= 10R or 50R selectable
S
value should be selected such that the
) at the inverting input of the amplifier.
G
) (Z
SENSE
S
Description
Ground
Connecting R10 to GND, (R50=N/C) selects a VOUT voltage that is 10X the voltage across
R
Output voltage proportional to the voltage across R
Positive supply terminal and power connection for the external Sense Resistor.
Load-side connection to the external Sense Resistor.
No Connect
No Connect
Connecting R50 to GND, (R10=N/C) selects a VOUT voltage that is 50X the voltage across
R
), is converted to an amplified
M
SENSE
SENSE
) / R (R
IN
L
) (R
is at full-scale for the load
– (I
.
.
S
) + V
L
G
) (R
(R
G
IO
S
+ Z
). The amplifier
]
M
))
IO
).
G
3
error component associated with the input offset
voltage of the internal op amp.
The IXI848 can be configured to measure a wide
selection of currents by using different R
values. Some common values for typical operation
of the IXI848 are listed in the following table.
Output Impedance
The VOUT output is a current source driving a
33kΩ resistance to ground for a gain of 10, or a
165kΩ resistance to ground for a gain of 50.
Output gain is reduced by resistive loading of the
VOUT terminal. The impedance of the external
monitor load (Z
to maintain the desired accuracy. Buffering of the
VOUT terminal with a high-impedance input stage
may be required to minimize output errors.
The following formulas quantify the percent error
introduced by output loading:
Full-Scale
I
For a Gain of 10
For a Gain of 50
R
0.15
L
100
1.5
LOAD
5
(A)
%
%
ERROR
ERROR
SENSE
= the external load applied to VOUT
.
= 100 [R
= 100 [R
R
R
0.001
M
0.01
SENSE
1.0
0.1
S
) should be chosen high enough
(
Ω)
LOAD
LOAD
Gain
(V/V)
/ (33kΩ + R
/ (165kΩ + R
10
10
50
50
VOUT (V)
V
SENSE
LOAD
LOAD
1.5
1.5
2.5
= 150mV
5
IXI848
) – 1]
06/29/05
) – 1]
SENSE