NXP Semiconductors

UM11597

PCF2131-ARD evaluation board

aaa-043565

PCFVDD

VBBS

VDD_3V3

SW4

PTS815

1

4

2

3

SW1

PTS815

1

4

2

3

J15

HDR_2X4

2

4

6

8

CLKOUT

6

TS1

8

TS2 9

TS3

10

TS4

11

BBS

14

VDD 15

VBAT

16

C1

0.1uF

SW3

PTS815

1

4

2

3

J10

HDR 2X5

1

2

3

4

6

5

7

8

9

10

SW2

PTS815

1

4

2

3

C2

0.1uF

PCFVDD

PCFBAT

VBBS

TS1

TS2

TS3

TS4

CLKOUT

TS1

TS2

TS3

TS4

Figure 3. PCF2131-ARD daughterboard, time stamp section

4.8 Power supply

Figure 4 represents the J9 section of the PCF2131-ARD schematic diagram.

aaa-043566

VBBS

VDD_3V3

VDD_3V3

PCFVDD

R5

330 OHM

BT1

HU2032-LF

2

1

3

C4

0.1uF

J9

HDR 2X5

1

1

1

2

3

4

6

5

5

7

8

9

10

C3

47uF

VBBS

PCFVDD

PCFBAT

PCFVDD

7

C3

47uF

R5

330 OHM 1

1

8

6

Figure 4. PCF2131-ARD daughterboard, J9 section; RC filter detail

J9 has several functions to configure the power rails feeding into PCX2131TF

1. Battery power (VBAT) connection:

When the evaluation board is provided, VBAT pin is grounded with a jumper placed

across J9.1&2. After interface selection (by placing jumpers on J1 or J2), user can

move this jumper to J9.3&4 to connect battery power to VBAT pin.

2. VDD connection:

User can evaluate to have a R/C filter placed before the VDD pin, or bypass the R/C

filter and directly feed VDD_3V3 to VDD pin.

By default, the R/C filter is recommended, and jumpers are placed across J9.6&8,

J9.5&7. The overall circuit is illustrated Figure 5.

To bypass the R/C filter, place a jumper across J9.5&6.

To measure current consumption, remove the jumper across J9.5&7, and place a

current meter across these two pins.

In some cases, the interface dongle itself can provide its own pullup resistors. If a

dongle is used with this EVM on J4, PCX2131TF could be powered through the

UM11597

All information provided in this document is subject to legal disclaimers.

© NXP B.V. 2021. All rights reserved.

User manual

Rev. 1.0 — 15 September 2021

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