MICRF009 データシートの表示（PDF） - Micrel

部品番号

コンポーネント説明

メーカー

MICRF009

QwikRadio® Low-Power UHF Receiver

Micrel 

Micrel

Functional Diagram

MICRF009

Figure 1. MICRF009 Block Diagram

Application Information and Function

Description

Refer to “MICRF009 Block Diagram.” Identified in the block

diagram are the three sections of the IC: 1) UHF

Downconverter, 2) OOK Demodulator, 3) Reference and

Control. Also shown in the figure are two capacitors (CTH,

CAGC) and one timing component, which is usually a

crystal or ceramic resonator. With the exception of a supply

decoupling capacitor and antenna impedance matching

network, these are the only external components needed

by the MICRF009 to assemble a complete UHF receiver.

For optimal performance it is highly recommended that the

MICRF009 is impedance-matched to the antenna. The

matching network will add additional two or three

components.

Four control inputs are shown in the block diagram: SEL0,

SEL1, SWEN, and SHUT. Using these logic inputs, the

user can control the operating mode and selectable

features of the IC. These inputs are CMOS compatible and

are internally pulled-up. The IF Bandpass Filter Roll-off

response of the IF Filter is 5th order, while the demodulator

data filter exhibits a 2nd order response.

Design Steps

The following steps are the basic design steps for using the

MICRF009 receiver:

1. Select the operating mode (sweep or fixed)

2. Select the reference oscillator

3. Select the demodulator filter bandwidth

4. Select the CTH capacitor

5. Select the CAGC capacitor

Step 1: Selecting The Operating Mode

Fixed-Mode Operation

For applications where the transmit frequency is set

accurately (that is, applications where a SAW or crystal-

based transmitter is used), the MICRF009 may be

configured as a standard superheterodyne receiver (fixed-

mode). In fixed-mode operation, the RF bandwidth is

narrower making the receiver less susceptible to interfering

signals. Fixed-mode is selected by connecting SWEN to

ground.

Sweep-Mode Operation

When used in conjunction with low-cost LC transmitters,

the MICRF009 should be configured in sweep-mode. In

sweep-mode, while the topology is still superheterodynes,

the local oscillator (LO) is swept over a range of

frequencies at rates greater than the data rate. This

technique effectively increases the RF bandwidth of the

January 18, 2005

6

M9999-011805

(408) 955-1690

Share Link: