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STEVAL-ISQ014V1
Low-side current sensing evaluation board
based on the TSZ121 op amp
Data brief
Description
The STEVAL-ISQ014V1 product evaluation board
implements low-side current sensing which
consists in placing a sense resistor between the
load and the circuit ground. The resulting voltage
drop is amplified using a TSZ121 op amp.
The common mode voltage is close to ground,
whatever the voltage of the power source, so the
current sense voltage can be amplified by this low
voltage op amp without restriction.
The circuit offers very stable electrical
characteristics over the entire supply voltage
range and is particularly suited for automotive and
industrial applications.
Features
• Very high accuracy: offset voltage 5 µV max at
25 °C, 8 µV over full temperature range (-40 °C
to 125 °C)
• Rail-to-rail input and output
Thanks to the highly accurate TSZ121 op amp,
precise current measurements can be made
through your application without the added cost of
high-precision resistors.
• Low supply voltage: 1.8 - 5.5 V
• Low power consumption: 40 µA max. at 5 V
• Gain bandwidth product: 400 kHz
• High tolerance to ESD: 4 kV HBM
• Extended temperature range: -40 to +125 °C
• Micro-packages: SC70-5 (TSZ121), DFN8 2x2
(TSZ122), and QFN16 3x3 (TSZ124)
• RoHS compliant
May 2014
DocID026324 Rev 1
For further information contact your local STMicroelectronics sales office.
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Schematic diagram
1
STEVAL-ISQ014V1
Schematic diagram
Figure 1. STEVAL-ISQ014V1 circuit schematic
Rf2
47k
In
Vccp
C1
Vccp
Rg2
100
22nF
Out
3
V+
4
Rg1
100
Rf1
47k
Cf
33nF
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TSZ121ILT
1
V-
2
Rsh
30m
GND
Vccn
6
Vcc
Vccn
Vout
STEVAL-ISQ014V1
2
Revision history
Revision history
Table 1. Document revision history
Date
Revision
08-May-2014
1
Changes
Initial release.
DocID026324 Rev 1
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STEVAL-ISQ014V1
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