February 17, 2005

11

M9999-021705

MICRF007

Micrel

Application Example

315MHz Receiver/Decoder Application

Figure 10 illustrates a typical application for the MICRF007

UHF Receiver IC. This receiver operates continuously (not

duty cycled) in fixed-mode, and features 6-bit address decod-

ing and two output code bits.

Operation in this example is at 315MHz, and may be cus-

tomized by selection of the appropriate frequency reference

(Y1), and adjustment of the antenna length. Changes from

the 1Kbps data rate may require a change in the value of R1.

A bill of materials accompanies the schematic.

C4

1.8pF

L1

56nH

1/4

monopole

antenna (23.1cm)

C2

39nF

C6

100pF

C5

100µF

C3

2.2µF

R3

100k

Y1

4.8970MHz

6-bit

address

Baseband

(Digital)

Ground

RF

(Analog)

Ground

+5V

Supply Input

C1

4.7µF

A0

A1

A2

A3

A4

A5

A6

A7

VSS

VDD

VT

OSC1

OSC2

DIN

D11

D10

D9

D8

VSS

ANT

VDD

CTH

REFOSC

CAGC

SHUT

DO

U1 MICRF007

U2 HT-12D

Code Bit 0

Code Bit 1

R1

68k

R2

1k

Figure 10. 315MHz, 1Kbps On-Off Keyed Receiver with Decoder

Bill of Materials

Item

Part Number

Manufacturer

Description

Qty.

C1

GRM21BF51A475ZA01L

4.7µF Y5V

1

C2

VJ0603Y393KXXA

39nF

1

C3

GRM188R61A225XE348

2.2µF X5R

1

C4

GRM1885C1H1R8CZ01B

1.8pF COG ceramic capacitor

1

C5

GRM188R71E104KA01B

100nF capacitor

1

C6

GRM1885C1H101JA01B

100pF capacitor

1

D1

SSF-LX100LID

red LED

1

L1

0603CS-56NX-B

56mH wire wound, Q=38

1

R1

CRCW06036812F

68k; 1/4W; 5%

1

R2

CRCW06031001F

1k; 1/4W; 5%

1

R3

CRCW06031003F

100k

1

U1

MICRF007BM

UHF Reciever

1

U2

HT-12D

Logic decoder

1

Y1

AB-4.8970MHZ-20-D

4.8970MHz crystal

1

Notes:

1. Vishay, tel. (203) 268-6261

2. Lumex, tel. (800) 278-5666

3. Micrel Inc., tel (408) 944-0800

4. Holteck, tel (408) 894-9046

5. Abracon, tel. (949) 448-7070

6. Coilcraft, tel. (510) 814-8954

7. Murata, tel (408) 397-1284