Micrel, Inc.

MICRF219A

July 2011

3

M9999-071811-A

Pin Description (Continued)

Pin

Number

Pin

Name

Pin Function

12

CTH

Demodulation Threshold Voltage Integration Capacitor. Connect a 0.1μF capacitor from CTH pin to GND

to provide a stable slicing threshold.

13

CAGC

AGC Filter Capacitor. Connect a capacitor from this pin to GND. Refer to the AGC Loop and CAGC

section for information on the capacitor value.

14

RSSI

Received Signal Strength Indicator. The voltage on this pin is an inversed amplified version of the voltage

on CAGC. Output is from a switched capacitor integrating op amp with 250Ω typical output impedance.

15

SCLK

Programming clock input.

16

RO2

Reference resonator connection to the Pierce oscillator. Internal capacitance of 7pF to GND during normal

operation.