Datasheet

0
10
20
30
40
50
60
70
80
100
0 0.5 1.0 1.5 2.0
I - Output Current - A
O
Efficiency - %
2.5 3.0
90
3.5
V = 3.3V, sw = 600 kHz
OUT
f
6Vin
12Vin
24Vin
36Vin
42Vin
0
10
20
30
40
50
60
70
80
100
0.001 0.01
I - Output Current - A
O
Efficiency - %
0.1
90
1
V = 3.3V, sw = 600 kHz
OUT
f
6Vin
12Vin
24Vin
36Vin
42Vin
www.ti.com Test Setup and Results
Be aware, changing the output voltage can affect the loop response. It may be necessary to modify the
compensation components. See the data sheet for details.
2 Test Setup and Results
This section describes how to properly connect, set up, and use the EVM. The section also includes test
results typical for the EVM covering efficiency, output voltage regulation, load transients, loop response,
output ripple, input ripple, start up, and shutdown.
2.1 I/O Connections
This EVM includes I/O connectors and test points as shown in Table 4. A power supply capable of
supplying at least 3.5 A must be connected to J2 through a pair of 20-AWG wires. The load must be
connected to J1 through a pair of 20-AWG wires. The maximum load-current capability must be 3.5 A.
Wire lengths must be minimized to reduce losses in the wires. Test-point TP1 provides a place to monitor
the V
IN
input voltages with TP2 providing a convenient ground reference. TP3 is used to monitor the output
voltage with TP4 as the ground reference.
Table 4. EVM Connectors and Test points
Reference Designator Function
J1 V
OUT
, 3.3 V at 3.5-A maximum
J2 V
IN
(see Table 1 for V
IN
range)
J3 EN jumper. Connect EN to ground to disable, open to enable.
TP1 V
IN
test point at V
IN
connector
TP2 GND test point at V
IN
TP3 Output voltage test point at V
OUT
connector
TP4 GND test point at V
OUT
connector
TP5 SW test point
TP6 V
OUT
test point used for loop response measurements
TP7 Test point between voltage divider network and output. Used for loop response measurements.
2.2 Efficiency
The efficiency of this EVM peaks at a load current of about 1.1 A with V
IN
= 12 V, and then decreases as
the load current increases towards full load. Figure 2 shows the efficiency for the EVM. Figure 3 shows
the light-load efficiency for the EVM using a semi-log scale. Figure 4 and Figure 5 show the efficiency with
V
OUT
adjusted to 5.0 V with 600-kHz switching frequency. Measurements are taken at an ambient
temperature of 25°C. The efficiency may be lower at higher ambient temperatures due to temperature
variation in the drain-to-source resistance of the internal MOSFET.
Figure 2. Efficiency Versus Load Current Figure 3. Light-Load Efficiency
5
SLVU794A–October 2012–Revised February 2013 Using the TPS54340 Step-Down Converter Evaluation Module
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