AT86RF230 datasheet(21/50 Pages) ATMEL

21 / 50 page

AT86RF230

5131A-ZIGB-06/14/06

range from 400 nF to 10 µF. A higher capacitor value provides better voltage stability, but increases the voltage

regulator settling time.

Bandgap

voltage

reference

1.25V

VDEC

VDD

VREG_TRIM[1:0]

Figure 6-1.

Simplified Schematic of VREG

The voltage regulators can be configured using the register 0x10 (VREG_CTRL). The read-only bit values

AVDD_OK = 1 and DVDD_OK = 1 indicate a stable, regulated supply voltage.

It is possible to use external voltage regulators instead of the internal regulators. For this special application the

internal regulators need to be switched off by setting the register bits to the values AVREG_EXT = 1 and

DVREG_EXT = 1. A regulated external supply voltage of 1.8V needs to be connected to the pins VDEC1 and

VDEC2. When turning on the external supply, ensure a sufficiently long stabilization time before interacting with the

AT86RF230.

6.5.

Battery Monitor

The battery monitor (BATMON) detects and signals a low battery or supply voltage. This is done by comparing the

current voltage on the VDD pins with a programmable internal threshold voltage. Figure 6-2 shows the simplified

schematic of the BATMON with the most important input and output signals.

BATMON_HR

BATMON_VTH

VDD

Threshold

Voltage

BATMON_OK

„1“

BATMON_IRQ

For input-to-output mapping

see control register

0x11 (BATMON)

DAC

clear

Figure 6-2.

Simplified Schematic of BATMON

AT86RF230 датащи(PDF) 21 Page - ATMEL Corporation