Datasheet
C (MIN)
O
³
1
2
(2 x7000)xLp
O
GND
VSNS
VIN
NC
NC
ENA
BOOT
PH
VIN
U1
TPS5410D
5V
7V 36V-
C1
4.7 Fm
C4
47 Fm
(Note A)
C2
0.01 Fm
L1
68 Hm
R2
3.24kW
D1
B340A
7
1
5
8
2
4
3
6
VOUT
ENA
R1
10kW
R3
1.78kW
C6
2700pF
C5
150pF
C7
0.056 Fm
C3
47 Fm
(Note A)
R2 +
R1 1.221
V
OUT
* 1.221
TPS5410
SLVS675C –AUGUST 2006–REVISED SEPTEMBER 2013
www.ti.com
Output Voltage Setpoint
The output voltage of the TPS5410 is set by a resistor divider (R1 and R2) from the output to the VSENSE pin.
Calculate the R2 resistor value for the output voltage of 12 V using Equation 12:
(12)
For any TPS5410 design, start with an R1 value of 10 kΩ. R2 is then 1.13 kΩ.
Boot Capacitor
The boot capacitor should be 0.01 μF.
Catch Diode
The TPS5410 is designed to operate using an external catch diode between PH and GND. The selected diode
must meet the absolute maximum ratings for the application: Reverse voltage must be higher than the maximum
voltage at the PH pin, which is VINMAX + 0.5 V. Peak current must be greater than IOUTMAX plus on half the
peak-to-peak inductor current. Forward voltage drop should be small for higher efficiencies. It is important to note
that the catch diode conduction time is typically longer than the high-side FET on time; therefore, the diode
parameters improve the overall efficiency. Additionally, check that the device chosen is capable of dissipating the
power losses. For this design, a Diodes, Inc. B340A is chosen, with a reverse voltage of 40 V, forward current of
3 A, and a forward voltage drop of 0.5 V.
Additional Circuits
Figure 12 shows an application circuit using all ceramic capacitors for the input and output filters. The design
procedure is similar to those given for the design example, except for the selection of the output filter capacitor
values and the design of the additional compensation components required to stabilize the circuit.
A. C3, C4 = Ceramic TDKC4532X5R1A476MT
Figure 12. 7-V — 36-V Input to 5-V Output Application Circuit with Ceramic Capacitors
Output Filter Capacitor Selection
When using ceramic output filer capacitors, the recommended LC resonant frequency should be no more than 7
kHz. Since the output inductor is already selected at 68 μH, this limits the minimum output capacitor value to:
(13)
14 Submit Documentation Feedback Copyright © 2006–2013, Texas Instruments Incorporated
Product Folder Links: TPS5410