NXP Semiconductors PCA9617ADP-ARD, User Manual, Page: 10 / 25

NXP Semiconductors
UM11763
PCA9617ADP-ARD user manual
4.6 Programmable power supplies
The PCA9617ADP-ARD contains two programmable power supplies: LDO1 and LDO2.
Figure 3 depicts the LDO sections of the schematic diagram. LDO1 provides the power
for VCCA, and LDO2 supplies VCCB power rail. Both regulators are controlled from the
EVK through the Arduino port.
4.6.1 LDO1
The programmable power supply LDO1 consists of an adjustable voltage regulator
LDK120M (U3), and the analog switch 74HCT4052D (U1). The analog switch selects the
resistor divider ratio in the feedback loop of the voltage regulator (U3). Table 2 shows
the output voltages of LDO1 as a function of switch position. U1 is controlled from the
Arduino port through “MUX1_LDO1_S0”, “MUX1_LDO1_S1”, “MUX1_EN_B” (pins 4, 5,
and 6 of the Arduino connector J5). The jumper header J19 allows the user to interrupt
the VCCA rail, to perform current measurements, or to supply VCCA from external.
MUX1_EN_B MUX1_LDO1_S1 MUX1_LDO1_S0 VCCA
High X (don’t care) X (don’t care) 0.8 V
Low Low Low 1.8 V
Low Low High 2.5 V
Low High Low 3.3 V
Low High High 4.96 V
Table 2. The VCCA programmable voltages
4.6.2 LDO2
The programmable power supply LDO2 is realized with the adjustable voltage regulator
MIC5301 (U4), and the analog switch 74HCT4052D (U2). Similarly, the analog switch
selects the resistor divider ratio in the feedback loop of the voltage regulator (U4). Table 3
shows the output voltages of LDO2 as a function of switch position. U1 is controlled from
the Arduino port through “MUX2_LDO2_S0” and “MUX2_LDO2_S1”, (pins 2 and 3 of the
Arduino connector J5). The control line “MUX2_EN_B” is connected to ground through
pulldown resistor R18. The jumper header J20 allows the user to interrupt the VCCB rail,
to perform current measurements, or to supply VCCB from external.
MUX2_LDO2_S1 MUX2_LDO2_S0 VCCB
Low Low 2.5 V
Low High 3 V
High Low 3.3 V
High High 4.96 V
Table 3. VCCB programmable voltages
UM11763 All information provided in this document is subject to legal disclaimers. © 2022 NXP B.V. All rights reserved.
User manual Rev. 1.0 — 22 July 2022
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