lt6109-1 Linear Technology Corporation, lt6109-1 Datasheet - Page 23

• Manufacturer Part Number: lt6109-1
• Description: High Side Current Sense Amplifer With Reference And Comparators
• Manufacturer: Linear Technology Corporation

APPLICATIONS INFORMATION
Drift of External Resistors: The drift of R1 and R
affects the accuracy of the trip point. Using resistors with
a drift of 50ppm/°C results in the following error:
Accuracy of External Sense Resistor: The load current is
converted to the sense voltage by R
of R
a 1% sense resistor results in a 1% error.
Table 2. Error Budget (Worst Case Over Temperature)
ERROR SOURCE
Amplifier Accuracy
Input Offset Voltage
Input Bias Current
Gain Error
Supply Rejection
Common Mode Rejection
Accuracy of R
Drift of R
Accuracy of External Sense Resistor
Drift of External Sense Resistor
Comparator/Reference Accuracy
Threshold Accuracy
Accuracy of R
Drift of R
Accuracy of External Sense Resistor
Drift of External Sense Resistor
2 • 50
SENSE
IN
IN
, R
, R
ppm
°C
contributes directly to the system error. Using
OUT
OUT
IN
IN
, R
, R
Resistors
Resistors
OUT
OUT
• 100°C = 1%
Resistors
Resistors
SENSE
. The tolerance
IN
also
LT6109 CIRCUIT CALCULATION
450µV/100mV • 100
350nA • 100Ω/100mV • 100
0.20%
(2µV/V • 1.2V)/100mV • 100
(7µV/V • 1.2V)/100mV • 100
Total Amplifier Accuracy
2 • 0.1%
2 • 50ppm/°C • 100°C • 100
1 • 1%
1 • 50ppm/°C • 100°C • 100
Total Amplifier Accuracy With External Resistors
2%
Total Comparator And Reference Accuracy
2 • 0.1%
2 • 50ppm/°C • 100°C • 100
1 • 1%
1 • 50ppm/°C • 100°C • 100
Total Comparator And Reference Accuracy with External Resistors 4.7
Drift of External Sense Resistor: The drift of R
affects accuracy. Using a sense resistor with a drift of
50ppm/°C results in the following error:
50ppm/°C • 100°C = 0.5%
LT6109-1/LT6109-2
% ERROR
0.45
0.035
0.2
0.002
0.008
0.7
0.2
1
1
0.5
3.4
2
2
0.2
1
1
0.5
SENSE
23
610912f
also