MICRF005

Micrel

MICRF005

2

October 2001

Pin Configuration

SEL0

T/R

REFOSC

VSSRF

N/C

VSSRF

CAGC

ANT

N/C

VDDRF

SHUT

VDDBB

DO

CTH

VSBB

MICRF005BM

114

213

312

411

510

69

78

Standard 14-Pin SOP (M) Package

Pin Description

Pin Number

Pin Name

Pin Function

1

T/R

Transmit/Receive control switch. Pull low to enable receiver function.

2, 3

VSSRF

This pin is the ground return for the RF section of the IC. The bypass

capacitor connected from the VDDRF to VSSRF should have the shortest

possible lead length. For best performance, connect VSSRF to VSSBB at

the power supply only (i.e. keep VSSBB currents from flowing through

VSSRF return paths).

4

ANT

This is the receive RF input, internally ac-coupled. Connect this pin to the

receive antenna. For applications located in high ambient noise environ-

ments, a fixed value band-pass network may be connected between the

ANT pin and VSSRF to provide additional receive selectivity and input

overload protection.

5

VDDRF

This pin is the positive supply input for the RF section of the IC. VDDBB and

VDDRF should be connected together directly at the IC pins.

6

VDDBB

This pin is the positive supply input for the baseband section of the IC.

VDDBB and VDDRF should be connected together at the IC pins.

7

CTH

This capacitor extracts the (DC) average value from the demodulated

waveform which becomes the reference for the internal data slicing com-

parator. Treat as a low-pass RC filter with source impedance of nominally

30k

Ω. A standard ±20% X7R ceramic capacitor is generally sufficient.

8

VSSBB

This is the ground return for the baseband section of the IC. The bypass and

output capacitors connected to VSSBB should have the shortest possible

leads lengths. For best performance, connect VSSRF to VSSBB at the

power supply only (i.e., keep VSSBB currents from flowing through VSSRF

return path).

9

DO

CMOS-level compatible data output signal.

10

SHUT

Shutdown-mode logic-level control input. Pull low to enable the receiver.

This pin is internally pulled-up to VDDRF.

11

NC

No connection

12

CAGC

Intergrating capacitor for on-chip AGC (Automatic Gain Control). The Decay/

Attack time-constant (TC) ratio is nominally set as 10:1. Use of 0.47

µF or

greater is strongly recommended for best range performance. Use low-

leakage type capacitors for duty-cycle operation (Dip Tantalum, Ceramic,

Polyester).

13

NC

No connection

14

REFOSC

This is the timing reference for on-chip tuning and alignment. Connect

crystal between this pin and VSSBB, or drive the input with an AC coupled

0.5V