LEON-G100 / LEON-G200 - System Integration Manual
GSM.G1-HW-09002-G3
Preliminary
System description
Page 20 of 125
LEON-G100
LEON-G200
12V
R5
C6
C1
VCC
INH
FSW
SYNC
OUT
GND
2
6
3
1
7
8
C3
C2
D1
R1
R2
L1
U1
50
VCC
GND
FB
COMP
5
4
R3
C4
R4
C5
Figure 7: Suggested schematic design for the VCC voltage supply application circuit using a low cost step-down regulator
Reference
Description
Part Number - Manufacturer
C1
22 µF Capacitor Ceramic X5R 1210 10% 25 V
GRM32ER61E226KE15 – Murata
C2
100 µF Capacitor Tantalum B_SIZE 20% 6.3V 15m
Ω
T520B107M006ATE015 – Kemet
C3
5.6 nF Capacitor Ceramic X7R 0402 10% 50 V
GRM155R71H562KA88 – Murata
C4
6.8 nF Capacitor Ceramic X7R 0402 10% 50 V
GRM155R71H682KA88 – Murata
C5
56 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H560JA01 – Murata
C6
220 nF Capacitor Ceramic X7R 0603 10% 25 V
GRM188R71E224KA88 – Murata
D1
Schottky Diode 25V 2 A
STPS2L25 – STMicroelectronics
L1
5.2 µH Inductor 30% 5.28A 22 m
Ω
MSS1038-522NL – Coilcraft
R1
4.7 k
Ω
Resistor 0402 1% 0.063 W
RC0402FR-074K7L – Yageo
R2
910
Ω
Resistor 0402 1% 0.063 W
RC0402FR-07910RL – Yageo
R3
82
Ω
Resistor 0402 5% 0.063 W
RC0402JR-0782RL – Yageo
R4
8.2 k
Ω
Resistor 0402 5% 0.063 W
RC0402JR-078K2L – Yageo
R5
39 k
Ω
Resistor 0402 5% 0.063 W
RC0402JR-0739KL – Yageo
U1
Step Down Regulator 8-VFQFPN 3 A 1 MHz
L5987TR – ST Microelectronics
Table 5: Suggested components for VCC voltage supply application circuit using a low cost step-down regulator
Low Drop-Out (LDO) linear regulator
The characteristics of the LDO linear regulator connected to
VCC
pin should meet the following requirements:
Power capabilities
: the LDO linear regulator with its output circuit has to be capable to provide a proper
voltage value to
VCC
pin and has to be capable to deliver 2.5 A current pulses with 1/8 duty cycle to
VCC
pin
Power dissipation
: the power handling capability of the LDO linear regulator has to be checked to limit its
junction temperature to the maximum rated operating range (i.e. check the voltage drop from the max input
voltage to the min output voltage to evaluate the power dissipation of the regulator)
Figure 8 and the components listed in Table 6 show an example of a power supply circuit, where the
VCC
module supply is provided by an LDO linear regulator capable to deliver 2.5 A current pulses, with proper power
handling capability. The use of a linear regulator is suggested when the difference from the available supply rail
and the VCC value is low: linear regulators provide good efficiency transforming a 5 V supply to the 3.8 V typical
value of the VCC supply.