Installation Instructions
LISA-U2 series - System Integration Manual
UBX-13001118 - R19 Early Production Information System description
Page 23 of 175
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
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
MSS1038-522NL – Coilcraft
R1
4.7 k Resistor 0402 1% 0.063 W
RC0402FR-074K7L – Yageo
R2
910 Resistor 0402 1% 0.063 W
RC0402FR-07910RL – Yageo
R3
82 Resistor 0402 5% 0.063 W
RC0402JR-0782RL – Yageo
R4
8.2 k Resistor 0402 5% 0.063 W
RC0402JR-078K2L – Yageo
R5
39 k Resistor 0402 5% 0.063 W
RC0402JR-0739KL – Yageo
U1
Step-Down Regulator 8-VFQFPN 3 A 1 MHz
L5987TR – ST Microelectronics
Table 8: Suggested components for low cost solution VCC voltage supply application circuit using a step-down regulator
Low Drop-Out (LDO) linear regulator
The characteristics of the LDO linear regulator connected to the VCC pins should meet the following
requirements:
Power capabilities: the LDO linear regulator with its output circuit must be capable of providing a proper
voltage value to the VCC pins and of delivering 2.5 A current pulses with 1/8 duty cycle
Power dissipation: the power handling capability of the LDO linear regulator must 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)
Output voltage slope: the use of the soft start function provided by some voltage regulators must be
carefully evaluated, since the voltage at the VCC pins must ramp from 2.5 V to 3.2 V within 1 ms to allow a
proper switch-on of the module
Figure 8 and the components listed in Table 9 show an example of a power supply circuit, where the VCC
module supply is provided by an LDO linear regulator capable of delivering 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 high efficiency when transforming a 5 V supply to
a voltage value within the module VCC normal operating range.
It is recommended to configure the LDO linear regulator so that it generates a voltage supply value slightly
below the maximum limit of the module VCC normal operating range (e.g. ~4.1 V as in the circuit described in
Figure 8 and Table 9). This reduces the power on the linear regulator and improves the thermal design of the
supply circuit.