MICRF620Z datasheet(18/21 Pages) MICREL

18 / 21 page

Micrel, Inc.

MICRF620/MICRF620Z

July 2006

M9999-120205

If FEE = -128 and still counting dwn-pulses:

1) =>-129 = +127

2) 126

3) 125

To avoid this situation, always make sure max count is

between limits.

Application Circuit Illustration

Figure 11. Circuit illustration of MICRF620, LDO and MCU

Figure 12 shows a typical set-up with the MICRF620, a

Low-Drop-Out voltage regulator (LDO)

and a mikro-

controller (MCU). When the MICRF620 and the MCU runs

on the same power supply (min 2.0, max. 2.5V), the IO

can be connected directly to the MCU. If the MCU needs a

higher VDD than the max. specified VDD of the MICRF620

(2.5V), voltage dividers need to be added on the IO lines

not to override the max. input voltage.

Figure 11 shows a recommended voltage divider circuit for

a MCU running at 3.0V and the MICRF620 at 2.5V.

3k3

18k

3k3

18k

3k3

18k

15k

MICRF6xx

MCU

SCLK

DATAIXO

DATACLK

RSSI

SCLK

DATAIXO

DATACLK

RSSI

Figure 12. How to connect MICRF620 (2.5V) and MCU (3.0V)

MICRF620Z Datasheet(PDF) 18 Page - Micrel Semiconductor