Datasheet
VIN
EN
GND
FB
V
IN
V
OUT
SS
C
in1
C
O1
R
fbt
Rcomp
C
comp
R
fbb
C
SS
U1
VOUT
LMZ10503
1
2
3
4, EP
5
6, 7
LMZ10503
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SNVS641I –JANUARY 2010–REVISED OCTOBER 2013
Over-Temperature Protection
When the LMZ10503 senses a junction temperature greater than 145°C (typ.), both switching MOSFETs are
turned off and the part enters a standby state. Upon sensing a junction temperature below 135° C (typ.), the part
will re-initiate the soft-start sequence and begin switching once again.
LMZ10503 Application Circuit Schematic and BOMs
This section provides several application solutions with an associated bill of materials. The compensation for
each solution was optimized to work over the full input range. Many applications have a fixed input voltage rail. It
is possible to modify the compensation to obtain a faster transient response for a given input voltage operating
point.
Figure 22.
Table 3. Bill of Materials, V
IN
= 3.3V to 5V, V
OUT
= 2.5V, I
OUT (MAX)
= 3A, Optimized for Electrolytic Input and
Output Capacitance
Designator Description Case Size Manufacturer Manufacturer P/N Quantity
U1 SIMPLE SWITCHER ® PFM-7 Texas Instruments LMZ10503 1
C
in1
150 µF, 6.3V, 18 mΩ C2, 6.0 x 3.2 x 1.8 mm Sanyo 6TPE150MIC2 1
C
O1
330 µF, 6.3V, 18 mΩ D3L, 7.3 x 4.3 x 2.8 Sanyo 6TPE330MIL 1
mm
R
fbt
100 kΩ 0603 Vishay Dale CRCW0603100KFKEA 1
R
fbb
47.5 kΩ 0603 Vishay Dale CRCW060347K5FKEA 1
R
comp
15 kΩ 0603 Vishay Dale CRCW060315K0FKEA 1
C
comp
330 pF, ±5%, C0G, 50V 0603 TDK C1608C0G1H331J 1
C
SS
10 nF, ±10%, X7R, 16V 0603 Murata GRM188R71C103KA01 1
Table 4. Bill of Materials, V
IN
= 3.3V, V
OUT
= 0.8V, I
OUT (MAX)
= 3A, Optimized for Solution Size and
Transient Response
Designator Description Case Size Manufacturer Manufacturer P/N Quantity
U1 SIMPLE SWITCHER ® PFM-7 Texas Instruments LMZ10503TZ 1
C
in1
, C
O1
47 µF, X5R, 6.3V 1206 TDK C3216X5R0J476M 2
R
fbt
110 kΩ 0402 Vishay Dale CRCW0402100KFKED 1
R
comp
1.0 kΩ 0402 Vishay Dale CRCW04021K00FKED 1
C
comp
27 pF, ±5%, C0G, 50V 0402 Murata GRM1555C1H270JZ01 1
C
SS
10 nF, ±10%, X7R, 16V 0402 Murata GRM155R71C103KA01 1
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