TS1103 Bidirectional Current-Sense Amplifier
Demo Board
Page 1
© 2014 Silicon Laboratories, Inc. All rights reserved.
FEATURES
RSENSE: 50mΩ ± 0.5%
Fully Assembled and Tested
2in x 2in 2-layer circuit board
COMPONENT LIST
DESIGNATION
QTY
DESCRIPTION
C2
1
47nF ±10%
capacitor (0805)
R1
1
50mΩ ± 0.5%
(0805)
U1
1
TS1103-25DB/
TS1103-50DB/
TS1103-100DB/
TS1103-200DB
VDD, VBATT,
VOUT, SIGN,
LOAD
5
Test points
DESCRIPTION
The demo board for the TS1103 is a completely
assembled and tested circuit board that can be used
for evaluating the bidirectional current-sense amplifier
for all (4) gain options; i.e., 25V/V, 50V/V, 100V/V,
and 200V/V.
The board is configured with an RSENSE =R1=50mΩ
resistor. The board has a dedicated RS+=VBATT,
RS-=LOAD, output voltage OUT=VOUT, VDD, and
SIGN test points. For additional information, refer to
the TS1103 product data sheet.
All TS1103s are available in a PCB-space saving
6-lead SOT23 surface-mount package.
Product data sheets and additional documentation
can be found at www.silabs.com.
ORDERING INFORMATION
Order Number
Description
TS1103-25DB
TS1103-XXX
Demo Board
TS1103-50DB
TS1103-100DB
TS1103-200DB
Figure 1. TS1103 Bidirectional Current-Sense Amplifier
Circuit
Figure 2. TS1103 Demo Board
TS1103 Bidirectional Current-Sense Amplifier Demo Board
Page 2 TS1103-EVB Rev. 1.0
DESCRIPTION
The TS1103 demo board includes decoupling
capacitor pads, C1, at the VBATT input pin and a
47nF capacitor at the VOUT output pin. Because the
TS1103 is a bidirectional current-sense amplifier, the
demo board can be set-up to sense current in both
directions. Please refer to Table 2 for the proper
connections of VBATT and LOAD test points. The
direction of the current is known based on the voltage
level of the SIGN pin. If VRS+>VRS-, the SIGN pin is a
logic HIGH or VDD voltage. If VRS->VRS+, the SIGN
pin is a logic LOW or GND voltage. A VDD test point
is available and powers the internal comparator that
monitors the direction of the load current. The output
voltage of the comparator is the voltage on the SIGN
pin.
QUICK START PROCEDURE
Required Equipment
A TS1103 demo board
A dual output, DC power supply, an HP Model
HP6624A or equivalent
Three digital voltmeters
A load resistor or an active load (value varies
depending on ILOAD desired)
Signal
Demo board
RS+
VBATT
RS-
LOAD
OUT
VOUT
GND
GND
VDD
VDD
SIGN
SIGN
Table 1. Demo Board Test Points
Test Point
VRS+>VRS-
VRS->VRS+
VBATT
input voltage
load
LOAD
load
input voltage
Table 2. VBATT and LOAD Test Point
Connections Per ILOAD Direction
GAIN
(V/V)
VBATT
(V)
ILOAD
(mA)
VDD
(V)
RLOAD
(Ω)
VOUT
(V)
MAX
VSENSE
(mV)
25
6
1600
1.8
3.75
2
80
50
6
800
1.8
7.5
2
40
100
6
400
1.8
15
2
20
200
6
200
1.8
30
2
10
Table 3. Demo Board Test Set-Up Per Gain Setting
To evaluate the TS1103 bidirectional current-sense
amplifier circuit, the following steps are to be
performed:
1) Before connecting the DC power supply to the
demo board, turn on the power supply, set the
DC voltage to 6V on one output and the other to
1.8V. Set the short circuit current limit on each
output to 10% higher than the maximum load
current in the application, and then turn it off.
2) For applications where VRS+>VRS-, connect the 6V
DC power supply positive terminal to the test
point VBATT and its negative terminal to the test
point GND. Connect the 1.8V power supply
positive terminal to the test point VDD and its
negative terminal to the test point GND. See
Table 2 for applications where VRS->VRS+.
3) Connect a digital voltmeter to the test points TP+
and TP- to measure VSENSE.
4) Connect the positive terminal of a second digital
voltmeter to the test point VOUT and the negative
terminal to the test point GND.
5) To monitor the direction of the current, connect
the positive terminal of a third digital voltmeter to
the test point SIGN and the negative terminal to
the test point GND.
6) Based on the selected gain option of the current
sense amplifier, select the load resistor or an
active load according to Table 3. Connect one
end of this resistor or active load to the test point
LOAD and the other end to the test point GND.
7) Turn on the power supply and observe the output
voltage at VOUT. The expression for the
TS1103’s output voltage is given by:
VOUT = ILOAD×50mΩ×ROUT
RGAIN[A/B]
where the TS1103’s internal ROUT and
RGAIN[A/B] resistor values are listed in Table 4.
GAIN(V/V)
RGAIN[A/B] (Ω)
ROUT (Ω)
25
400
10k
50
200
10k
100
100
10k
200
100
20k
Table 4. TS1103’s Internal Gain Setting
Resistors (typical values)
TS1103 Bidirectional Current-Sense Amplifier Demo Board
Silicon Laboratories, Inc. Page 3
400 West Cesar Chavez, Austin, TX 78701 TS1103-EVB Rev. 1.0
+1 (512) 416-8500 ▪ www.silabs.com
8) The TS1103’s actual output voltage VOUT will
depend on the TS1103’s actual offset voltage
VOS, its gain error GE, sense resistor (RSENSE)
tolerance of ±1%, and the load resistor
tolerance/active load accuracy. Note: For applications where VRS->VRS+, connect test
points VBATT and LOAD based on Table 2 and
follow the steps above.
Figure 3. Top Layer Component View
Figure 4. Top Layer Trace View
Figure 5. Bottom Layer (GND)
