MICRF011BN Datasheet MICRF011BM, MICRF011BM-TR, MICRF011BN | P1-P3

Micrel Inc. • 1849 Fortune Drive San Jose, Ca 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

MICRF011

QwikRadio

Receiver/Data Demodulator

Preliminary Information

General Description

The MICRF011, an enhanced version of the MICRF001, is a single chip

OOK (ON-OFF Keyed) Receiver IC for remote wireless applications,

employing Micrel’s latest QwikRadio

technology. This device is a true

“antenna-in, data-out” monolithic device. All RF and IF tuning is

accomplished automatically within the IC, which eliminates manual

tuning and reduces production costs. Receiver functions are completely

integrated. The result is a highly reliable yet extremely low cost solution

for high volume wireless applications. Because the MICRF011 is a true

single-chip radio receiver, it is extremely easy to apply, minimizing design

and production costs, and improving time to market.

The MICRF011 is a functional and pin equivalent upgrade to the

MICRF001, providing improved range, lower power consumption, and

higher data rate support when in FIXED mode.

The MICRF011 provides two fundamental modes of operation, FIXED

and SWP. In FIXED mode, the device functions like a conventional

superheterodyne receiver, with an (internal) local oscillator fixed at a

single frequency based on an external reference crystal or clock. As with

any conventional superheterodyne receiver, the transmit frequency must

be accurately controlled, generally with a crystal or SAW (Surface

Acoustic Wave) resonator.

In SWP mode, the MICRF011 sweeps the (internal) local oscillator at

rates greater than the baseband data rate. This effectively “broadens”

the RF bandwidth of the receiver to a value equivalent to conventional

super-regenerative receivers. Thus the MICRF011 can operate with less

expensive LC transmitters without additional components or tuning, even

though the receiver topology is still superheterodyne. In this mode the

reference crystal can be replaced with a less expensive ± 0.5% ceramic

resonator.

All post-detection (demodulator) data filtering is provided on the

MICRF011, so no external filters need to be designed. Any one of four

filter bandwidths may be selected externally by the user. Bandwidths

range in binary steps, from 0.625kHz to 5kHz (SWP mode) or 1.25kHz to

10kHz (FIXED mode). The user only needs to program the appropriate

filter selection based on data rate and code modulation format.

Features

• Complete UHF receiver on a monolithic chip

• Frequency range 300 to 440 MHz

• Typical range over 200 meters with monopole

antenna

• Data rates to 2.5kbps (SWP), 10kbps (FIXED)

• Automatic tuning, no manual adjustment

• No Filters or Inductors required

• Low Operating Supply Current—2.4 mA at 315MHz

• Fully pin compatible with MICRF001

• Very low RF re-radiation at the antenna

• Direct CMOS logic interface to standard decoder

and microprocessor ICs

• Extremely low external part count

Applications

• Garage Door/Gate Openers

• Security Systems

• Remote Fan/Light Control

IMPORTANT: Items in bold type represent changes from

the MICRF001 specification. Differences between the

MICRF001 and -011 are identified in table 2, together with

design considerations for using the -011 in present

MICRF001 designs.

Typical Operating Circuit

385.5 MHz, 1200 bps OOK RECEIVER

QwikRadio

December 1998b MICRF011

MICRF011 Micrel

Ordering Information

Part Number Temperature Range Package

MICRF011BN

-40°C to +85°C

14-Pin DIP

MICRF011BM

-40°C to +85°C

14-Pin SOIC

Pin Configuration (DIP and SOIC)

Pin Description

Pin Number Pin Name Pin Function

1 SEL0 Programs desired Demodulator Filter Bandwidth. This pin in internally pulled-up to VDD. See Table 1.

2/3 VSSRF This pin is the ground return for the RF section of the IC. The bypass capacitor connected from 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 path).

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

impedance is high (FET gate) with approximately 2pF of shunt (parasitic) capacitance. For applications

located in high ambient noise environments, a fixed value band-pass network may be connected between

the ANT pin and VSSRF to provide additional receive selectivity and input overload protection. (See

“Application Note 22, MICRF001 Theory of Operation”.)

5 VDDRF This pin is the positive supply input for the RF section of the IC. VDDBB and VDDRF should be connected

directly at the IC pins. Connect a low ESL, low ESR decoupling capacitor from this pin to VSSRF, as short

as possible.

6 VDDBB This pin is the positive supply input for the baseband section of the IC. VDDBB and VDDRF should be

connected directly 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 comparator. Treat this as a low-pass RC filter with source impedance

of 118kohms (for REFOSC frequency ft=4.90MHz). Note that variation in source resistance with filter

selection no longer exists, as it does for the MICRF001. (See “Application Note 22, MICRF001 Theory

of Operation”, section 6.4). A standard ± 20% X7R ceramic capacitor is generally sufficient.

8 DO Output data pin. CMOS level compatible.

9/10 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 lead lengths. For best performance, connect VSSRF to

VSSBB at the power supply only (i.e., keep VSSBB currents from flowing through VSSRF return path).

11 CAGC Integrating capacitor for on-chip receive AGC (Automatic Gain Control). The Decay/Attack time-constant

(TC) ratio is nominally set as 10:1. Use of 0.47µF or greater is strongly recommended for best range

performance. See “Application Note 22, MICRF001 Theory of Operation” for further information.

12 SEL1 Programs desired Demodulator Filter Bandwidth. This pin in internally pulled-up to VDD. See Table 1.

13 REFOSC This is the timing reference for on-chip tuning and alignment. Connect either a ceramic resonator or crystal

(mode dependent) between this pin and VSSBB, or drive the input with an AC coupled 0.5Vpp input clock.

Use ceramic resonators without integral capacitors.

Note that if operated in FIXED mode, a crystal must be used; however in SWP mode, one may use either a

crystal or ceramic resonator. See “Application Note 22, MICRF001 Theory of Operation” for details on

frequency selection and accuracy.

14 SWEN This logic pin controls the operating mode of the MICRF011. When SWEN = HIGH, the MICRF011 is in

SWP mode. This is the normal (default) mode of the device. When SWEN = LOW, the device operates

as a conventional single-conversion superheterodyne receiver. (See “Application Note 22, MICRF001

Theory of Operation” for details.) This pin is internally pulled-up to VDD.

QwikRadio

December 1998b MICRF011

MICRF011 Micrel

SEL0 SEL1 Demodulator Bandwidth (Hz)

SWP Mode FIXED Mode

1 1

5000 10000

0 1

2500 5000

1 0

1250 2500

0 0

625 1250

Table 1

Nominal Demodulator (Baseband) Filter Bandwidth

vs. SEL0, SEL1 and Mode

Design Change Retrofit Design Action

1. Local Oscillator sweep range

reduced 2X. Affects SWP mode

only.

Reconsider Tx/Rx Frequency Alignment Error Budget, per App. Note 22.

If alignment tolerances cannot be met, consider:

(1) tighten ceramic resonator tolerance,

(2) replace ceramic resonator with crystal, or

(3) not to upgrade to -011

2. Local Oscillator sweep rate reduced

2X. Affects SWP mode only.

Impacts SWP mode maximum data rate.

If data rate constraint cannot be met, consider

(1) reduce system data rate by 2X, or

(2) not to upgrade to -011

3. IF Center Frequency reduced 2X.

Affects both modes SWP and

FIXED.

Factor this change into Tx/Rx Frequency Alignment Error Budget.

FIXED mode users of -001 must change crystal frequency.

4. IF Bandwidth reduced 2X. Affects

both modes SWP and FIXED.

Factor this change into Tx/Rx Frequency Alignment Error Budget.

5. FIXED mode Demod Filter cutoff

frequencies increased 2X. Affects

FIXED mode only.

For FIXED mode only, choose next lower filter frequency (via control pins

SEL0/1), to maintain same range performance

6. CTH Pin Impedance

118kΩ @ ft=4.90 MHz [see Note 4].

Affects both modes SWP and

FIXED.

Recompute appropriate value of CTH capacitor, and change value on PCB

Table 2

MICRF001/011 Change List and

Design Retrofit Guidelines

P1-P3 P4-P6 P7-P9 P10-P11

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