Datasheet

-
OUT
V
R9 = R10 ×( 1)
0.6 V
)V(.
)ms(Tss)A(.
)nF(C
60
42
7
´m
=
æ ö
-
ç ÷
è ø
æ ö
- +
ç ÷
è ø
ENFALLING
START STOP
ENRISING
ENFALLING
p h
ENRISING
V
V V
V
R1 =
V
I 1 I
V
( )
´
- + +
ENFALLING
STOP ENFALLING p h
R1 V
R2 =
V V R1 I I
www.ti.com Introduction
1.3 Modifications
These evaluation modules are designed to provide access to the features of the TPS54519. Some
modifications can be made to this module.
1.3.1 Output Voltage Set Point
The voltage divider R9 and R10 is used to set the output voltage. To change the output voltage of the
EVM, it is necessary to change the value of resistor R9. Changing the value of R9 can change the output
voltage above 0.6 V. The value of R9 for a specific output voltage can be calculated using Equation 1.
Use 10 kΩ for R10.
(1)
Table 3 lists the R9 and R10 values for some common output voltages. Note that V
IN
must be in a range
so that the minimum on-time is greater than 80 ns, and the maximum duty cycle is less than 92%. The
values given in Table 3 are standard values, not the exact value calculated using Equation 1.
Table 3. Output Voltages Available
Output Voltage (V) R9 Value (kΩ) R10 Value (kΩ)
1 6.65 10
1.2 10 10
1.5 15 10
1.8 20 10
2.5 31.6 10
1.3.2 Slow-Start Time
The slow-start time can be adjusted by changing the value of C7. Use Equation 2 to calculate the required
value of C7 for a desired slow-start time
(2)
C7 is set to 0.01 μF on the EVM for a default slow-start time of 2.5 msec.
1.3.3 Adjustable UVLO
The undervoltage lockout (UVLO) can be adjusted externally using R1 and R2. The EVM is set for a start
voltage of 2.794 V and a stop voltage of 2.595 V using R1 = 14.3 kΩ and R2 = 11.5 kΩ. Use Equation 3
and Equation 4 to calculate required resistor values for different start and stop voltages.
(3)
(4)
Where:
• V
ENRISING
= 1.25 V
• V
ENFALLING
= 1.18 V
• I
h
= 2.9 µA
• I
p
= 0.7 µA
3
SLVU523–September 2011 TPS54519EVM-037, 5-A, SWIFT™ Regulator— Evaluation Module
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