Micrel RadioWire MICRF507 Manual

470mhz to 510mhz low-power fsk transceiver with +10dbm power amplifier

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General Description

The MICRF507 is a fully-integrated FSK transceiver with

+10dBm power amplifier and transmit/receive switch. The

device is targeted at automated meter reading (AMR)

applications in the China Short Range Device (SRD)

frequency band of 470MHz to 510MHz. The device

supports data rates up to 20kbps with PLL divider

modulation and up to 200kbps with VCO modulation. The

receiver achieves a sensitivity of -113dBm at a data rate of

2.4kbps while only consuming 12mA of supply current.

The integrated power amplifier (PA) delivers +10dBm of

output power while only consuming 21.5mA of supply

current. Power down supply current is a low 0.2µA while

retaining register information and a low 280µA in standby

mode where only the crystal oscillator is enabled.

The receiver of the MICRF507 utilizes a Zero IF (ZIF) I/Q

architecture, integrating a low-noise amplifier (LNA) with

bypass mode, I/Q quadrature mixers, three-pole Sallen-

Key IF channel pre-filters, and six-pole elliptic switched

capacitor IF filters, providing excellent selectivity, adjacent

channel

rejection

and

demodulation is implemented digitally and a synchronizer,

when enabled, recovers the received bit clock. A receive

signal strength indicator (RSSI) circuit indicates the

received signal level over a 50dB range. An integrated

Frequency Error Estimator (FEE) and crystal tuning

capability allow fine tuning of the RF frequency.

The transmitter of the MICRF507 consists of an FSK

modulator and power

adjustable from +10dBm to -3.5dBm in seven steps.

Modulation can be achieved by applying two sets of PLL

divider ratios or through direct VCO modulation by varying

VCO tank capacitance.

The MICRF507 requires a 2.0V to 2.5V supply voltage,

operates over the -40˚C to +85˚C temperature range, and

is available in a 32-pin QFN package.

RadioWire is a registered trademark of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

October 2, 2013

blocking

performance.

amplifier with output power

470MHz to 510MHz Low-Power FSK

Transceiver with +10dBm Power Amplifier

Features

• -113dBm sensitivity at 2.4kbps encoded bit rate

• +10dBm power amplifier with seven gain steps

• 12mA receive supply current

• 21.5mA transmit supply current at +10dBm

• 0.2μA power down current (registers retain settings)

• 280µA standby current (crystal oscillator enabled)

• Data rates up to 20kbps with PLL divider modulation

• Data rates up to 200kbps with VCO modulation

• Integrated transmit and receive (T/R) switch

• LNA with bypass mode

• Zero IF I/Q receiver architecture

• IF pre-amplifiers with DC-offset removal

• Three-pole Sallen-Key IF channel low-pass pre-filter

FSK

• Six-pole elliptic switched capacitor IF low-pass filter

• 50kHz to 350kHz programmable baseband bandwidth

• 59dB blocking at ±1MHz offset

• 53dB adjacent channel rejection at ±500kHz offset

• FSK digital demodulator with clock recovery

• 50dB Received Signal Strength Indicator (RSSI)

• Frequency Error Estimator (FEE)

• Reference crystal tuning capability

• 2.0 to 2.5V supply voltage range

• -40˚C to +85˚C operating temperature range

• Available in 32-pin QFN package

(5.0mm × 5.0mm × 0.85mm)

Applications

• China Short Range Device (SRD) Communications

• Automated Meter Reading (AMR)

• Advanced Metering Infrastructure (AMI)

• Wireless Remote Meter Reading

MICRF507

RadioWire

Revision 2.2

Table of Contents

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Summary of Contents for Micrel RadioWire MICRF507

Page 1 • Wireless Remote Meter Reading RadioWire is a registered trademark of Micrel, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com October 2, 2013...
Page 2: Table Of Contents
Micrel, Inc. MICRF507 ® RadioWire FSK Transceiver Selection Guide ........................ 4 Ordering Information ................................. 4 Pin Configuration ................................4 Pin Description ................................... 4 Block Diagram ..................................6 Absolute Maximum Ratings .............................. 7 Operating Ratings ................................7 Electrical Characteristics ..............................7 Functional Description ..............................
Page 3 Micrel, Inc. MICRF507 Bill of Materials ................................. 36 Layout Considerations ..............................37 Layer Definition ..............................37 Grounding................................37 RF Traces................................37 Supply Routing ..............................37 PLL Loop Filter ..............................37 Overview of Programming Bits............................38 Detailed Description of Programming Bits ........................39 Package Information and Recommended Landing Pattern ..................
Page 4: Fsk Transceiver Selection Guide
Micrel, Inc. MICRF507 ® RadioWire FSK Transceiver Selection Guide Maximum Data Receive Part Number Frequency Range Supply Voltage Transmit Current Package Rate Current MICRF505 850MHz to 950MHz 200kbps 13.5mA 2.0 to 2.5V 28mA QFN-32 MICRF505L 850MHz to 950MHz 200kbps 13.5mA 2.25 to 5.5V...
Page 5 Micrel, Inc. MICRF507 Pin Description (Continued) Pin Number Pin Name Type Pin Function 8, 16, 17, 32 No connect. Leave these pins floating. CIBIAS Connection for bias resistor. IFVDD IF/mixer power supply. IFGND IF/mixer ground. ICHOUT Test pin. QCHOUT Test pin.
Page 6: Block Diagram
Micrel, Inc. MICRF507 Block Diagram October 2, 2013 Revision 2.2...
Page 7: Absolute Maximum Ratings
Micrel, Inc. MICRF507 Absolute Maximum Ratings Operating Ratings Supply Voltage (V ) ........... +2.7V Supply Voltage (V ) ........+2.0V to +2.5V Voltage on any pin (GND = 0V)....-0.3V to +2.7V RF Frequencies ........ 470MHz to 510MHz Lead Temperature (soldering, 4sec.) ......300°C Encoded Bit Rate ..........200kbps...
Page 8 Micrel, Inc. MICRF507 Electrical Characteristics (Continued) = 490MHz, f = 16MHz, MICRF507 Development Board, Modulation type = closed-loop VCO modulation, Sync_en bit = 1, XTAL = 2.5V; T = 25°C, the term “bit rate” refers to encoded bit rate throughout the EC table (see Figure 24), bold values indicate –40°C<...
Page 9 Micrel, Inc. MICRF507 Electrical Characteristics (Continued) = 490MHz, f = 16MHz, MICRF507 Development Board, Modulation type = closed-loop VCO modulation, Sync_en bit = 1, XTAL = 2.5V; T = 25°C, the term “bit rate” refers to encoded bit rate throughout the EC table (see Figure 24), bold values indicate –40°C<...
Page 10: Functional Description
Micrel, Inc. MICRF507 Functional Description Control (3-wire) Interface General The IO is an input for entry of starting addresses, the R/W The MICRF507 operation is controlled through a set of 8- bit, and bytes being written to registers, and an output for bit registers.
Page 11 Micrel, Inc. MICRF507 Data Field A6…A0 0000000 LNA_by Sync_en Mode1 Mode0 ’1’ 0000001 Modulation1 Modulation0 ‘0’ ‘0’ RSSI_en LD_en PF_FC1 PF_FC0 0000010 CP_HI SC_by ‘0’ PA_By OUTS3 OUTS2 OUTS1 OUTS0 0000011 ‘1’ ‘1’ ‘0’ VCO_IB2 VCO_IB1 VCO_IB0 VCO_freq1 VCO_freq0 0000100...
Page 12 Micrel, Inc. MICRF507 Writing • This method is used to write either to one register (see Clock in one or more bytes, MSB of each byte Figure 1), or any number of registers with consecutive first. addresses up to all 22 writeable registers (see Figure 2) in •...
Page 13: Reading
Micrel, Inc. MICRF507 • Reading Clock out 8 bits per register (one or more) to be read through IO, MSB first. Rising edges of SCLK Any number of registers with consecutive addresses, from bring each bit to IO. The user can then one up to all 23, can be read.
Page 14: Control Interface Timing
Micrel, Inc. MICRF507 Control Interface Timing Power-on Reset Figure 4 and Table 2 give the timing specifications for the The power-on reset time (t ), given in Table 2, is defined control interface. as the time from application of supply voltage to completion of power on reset.
Page 15: Clock Generation
Micrel, Inc. MICRF507 Clock Generation The MICRF507’s crystal oscillator: Figure 6 shows the oscillator with its frequency-shifting capacitor bank (controlled by the register field XCOtune) • Serves as the reference for the synthesizer that is and the frequency dividers that derive the latter three the carrier and local oscillator source.
Page 16: Crystal Oscillator (Xco)
Micrel, Inc. MICRF507 To achieve 9pF load capacitance required to center Crystal Oscillator (XCO) TN4-26011 at 16MHz, set the external capacitors to The crystal oscillator’s role as the synthesizer reference 1.5pF and XCOtune=16 . Figure 8 shows the tuning demands very good phase and frequency stability. As range for two different capacitor values, 1.5pF and zero...
Page 17: Bitsync_Clk (Receiver Bit Synchronization Clock)
Micrel, Inc. MICRF507 An external reference clock, when used instead of a The modulator clock is used if VCO modulation method crystal, should be applied to pin 24 (XTALOUT) with pin is selected. Set the modulator clock frequency to either 23 (XTALIN) not connected.
Page 18 Micrel, Inc. MICRF507 Number Location Reference Description Field Name of bits of bits Sync_en Reg0[3] Synchronizer Mode bit Table 7 Table 6. Register Bit Fields for Data Interface and Bit Synchronization Sync_en State Comments RX: Bit synchronization off Transparent reception of data...
Page 19: Sync_En = 0
Micrel, Inc. MICRF507 Mode Sync_en DATACLK DATAIXO Direction Signal Direction Signal/Function Input Modulates carrier directly Output (asynchronously) Transmit Input Sampled at rising edge of BitRate Output BitRate clock clock; latched output modulates carrier Output Output Raw output from demodulator Output...
Page 20: Frequency Synthesizer
Micrel, Inc. MICRF507 Frequency Synthesizer The MICRF507 frequency synthesizer is an integer-N after filtering, controls the VCO, closing the loop and forcing phase-locked loop consisting of: the error between the reference frequency and the divided VCO frequency to zero. •...
Page 21 Micrel, Inc. MICRF507 Loop filter Downconverter A-Divider Prescaler N-Divider Charge pump Div 2 Phase detector Div 2 M-Divider Figure 12. PLL Block Diagram A6…A0 0001010 A0_5 A0_4 A0_3 A0_2 A0_1 A0_0 0001011 N0_11 N0_10 N0_9 N0_8 0001100 N0_7 N0_6 N0_5...
Page 22: Vco
Micrel, Inc. MICRF507 N, M, and A are numbers of length 12, 12 and 6 bits, The input capacitance at the varactor pin must be taken respectively The synthesizer’s output frequency can be into consideration when designing the PLL loop filter. This...
Page 23: Lock Detect
(pin 29) of 6pF can be neglected for the two filters with lowest bandwidth (which have R2=0 and relatively large values of C1). For other loop bandwidth and phase detector values, use the loop filter calculation tool in RF Testbench software available on Micrel’s website. Encoded Charge...
Page 24: Receiver
Micrel, Inc. MICRF507 Receiver Number Location Description Reference of bits of bits Field Name By_LNA Reg0[7] LNA bypass on/off PF_FC Reg1[1:0] Pre-filter corner frequency Table 14 SC_by Reg2[6] Bypass of switched capacitor filter on/off ScClk Reg8[4:0] Switched Cap clock divider...
Page 25: Sallen-Key Filters
Micrel, Inc. MICRF507 The front end’s input impedance, with no matching The pre-filter and switched-capacitor filters in cascade network, is close to 50Ω as shown in Figure 15. This gives must pass the full IF bandwidth of the received signal. In a an input reflection coefficient of about -13dB.
Page 26: Fee
Micrel, Inc. MICRF507 Another use for RSSI is to determine that transmit power The result of the measurement, read from the FEE register can be reduced in a system. If the RSSI detects a strong at address 22 (16 hex, 0010110 binary), is actually an signal, the transmitter could be alerted to reduce its eight-bit two’s complement signed number, which can...
Page 27: Xcotune Procedure Example
Micrel, Inc. MICRF507 XCOtune Procedure Example Registers properly set for reception; A procedure such as the algorithm given below can be LOOP: called during production (storing the calibrated XCO_tune value), at regular intervals, or implemented in the XCO_Step = XCO_Step/2;...
Page 28: Transmitter
Micrel, Inc. MICRF507 Transmitter Power Amplifier The maximum output power of the power amplifier (PA) is Setting PA_by=1 causes the PA to be bypassed and approximately 10dBm with a 50Ω load. For maximum output power to drop by ~22dB. It is still possible to control output power, the load seen by the PA must be resistive.
Page 29: Frequency Modulation
Micrel, Inc. MICRF507 Modulation1 Modulation0 State 39pF 12nH Closed loop VCO-modulation ANT (pin 5) Not in use Modulation by A,M and N 12pF 12pF Not in use Table 18. Modulation Field Figure 18. LC Filter Bits from the microcontroller to be transmitted enter at the This filter is designed for the 490MHz band with 50Ω...
Page 30: Divider Modulation
Micrel, Inc. MICRF507 Divider Modulation as to “round” the waveform and reduce the transmission spectral width. When Modulation[1:0] = 10, two sets of divider values need to be programmed. The divider values stored in the The amplitude of the modulating waveform, and therefore M0, N0, and A0 registers are selected to transmit a ‘0’...
Page 31 Micrel, Inc. MICRF507 Frequency Deviation under VCO Modulation To avoid saturation in the modulator, it is important not to exceed maximum Mod_I. Maximum Mod_I for a given Three factors determine the deviation at which the data is given by: stream is modulated: modulator clock frequency, capacitor...
Page 32: Modulator Filter
Micrel, Inc. MICRF507 Figure 22 shows two waveforms with different attenuator Mod_Aa < Mod_Ab setting: . If Mod_A is increased, the frequency deviation is lowered and vice versa. The resulting frequency deviation in terms of the parameters discussed above is given in the following...
Page 33: System Modes And Initialization
Micrel, Inc. MICRF507 When using VCO modulation; after MICRF507 has been System Modes and Initialization put in transmit mode, the microcontroller will tri-state the driver connected to DATAIXO pin to leave that pin floating Start-up and Initialization until the microcontroller begins sending data. This is...
Page 34: Message Coding And Formatting
Micrel, Inc. MICRF507 Message Coding and Formatting DC Balanced Line Coding Data Word A Word B Line coding, diagrammed in Figure 24, is used when a 1011 0100 communication channel imposes constraints on bit sequences. An encoding stage that ensures DC balance 1100 (equal numbers of ‘1’...
Page 35: Typical Application
Micrel, Inc. MICRF507 Typical Application October 2, 2013 Revision 2.2...
Page 36 12nH, ±5%, Size 0603 TSX-10A16.0000MHz: Toyocom 16MHz, 9pF, 10/10ppm TN4-26011 470MHz to 510MHz Low-Power FSK Transceiver (10) MICRF507 Micrel, Inc. with +10dBm Power Amplifier Notes: Murata: www.murata.com Vishay: www.vishay.com Coilcraft: www.coilcraft.com Toyocom: www.epsontoyocom.co.jp/english 10. Micrel, Inc.: www.micrel.com October 2, 2013 Revision 2.2...
Page 37 50Ω as well. Refer to design. These are discussed below, and a recommended the Micrel Development Board layout, or a transmission layout found...
Page 38 Micrel, Inc. MICRF507 Overview of Programming Bits Address Data Field Field A6..A0 0000000 LNA_by Sync_en Mode1 Mode0 Load_en OL_opamp_en PA_LDc_en 0000001 Modulation1 Modulation0 RSSI_en LD_en PF_FC1 PF_FC0 (“0”) (”0”) VCO_by 0000010 CP_HI SC_by PA_by OUTS3 OUTS2 OUTS1 OUTS0 (“0”) IFBias_s...
Page 39 Micrel, Inc. MICRF507 Detailed Description of Programming Bits ADR # BIT # Name Description Comments 0000000 By_LNA LNA bypass on/off Power amplifier level, 3.bit Reference Table 17 Power amplifier level, 2.bit Reference Table 17 Power amplifier level, 1.bit Reference Table 17...
Page 40 Micrel, Inc. MICRF507 ADR # BIT # Name Description Comments Mod_I0 Modulator current setting, LSB 0000101 --------- Reserved/not in use --------- Reserved/not in use Mod_FHG “0” mandatory. Modulator Test bit. Mod_shape “1” mandatory.Modulator shape enable Mod_A3 Modulator attenuator setting, LSB...
Page 41 Micrel, Inc. MICRF507 ADR # BIT # Name Description Comments XCOtune0 Crystal oscillator trimming, MSB 0001010 --------- Reserved/not in use --------- Reserved/not in use A0_5 A0-counter 6.bit A0_4 A0-counter 5.bit A0_3 A0-counter 4.bit A0_2 A0-counter 3.bit A0_1 A0-counter 2.bit A0_0 A0-counter 1.bit...
Page 42 Micrel, Inc. MICRF507 ADR # BIT # Name Description Comments A1_5 A1-counter 6.bit A1_4 A1-counter 5.bit A1_3 A1-counter 4.bit A1_2 A1-counter 3.bit A1_1 A1-counter 2.bit A1_0 A1-counter 1.bit 0010000 --------- Reserved/not in use --------- Reserved/not in 7use --------- Reserved/not in use...
Page 43 Micrel, Inc. MICRF507 ADR # BIT # Name Description Comments “1” mandatory. Bias current setting of LObuffer, 1. bit LO_IB0 (01 = typical current) “0” mandatory. Bias current setting of PA, 2. bit (11 = PA_IB4 highest current) “0 mandatory. Bias current setting of PA, 1. bit (01 =...
Page 44 Micrel, Inc. MICRF507 Number Location Category Field Name Description Reference of Bits of Bits XCOtune Reg9[4:0] Crystal oscillator trimming RefClk_K Reg7[5:0] Reference clock divider Reg6[0], BitRate_clkS Bitrate clock setting Reg7[7:6] Mod_clkS Reg6[6:4] Modulator clock setting BitSync_clkS Reg6[3:1] BitSync clock setting...
Page 45 Micrel, Inc. MICRF507 OutS3 OutS2 OutS1 OutS0 IchOut QchOut Ichout2 / RSSI QchOut2 / NC Ip mixer In mixer Ip IFamp In IFamp Qp mixer Qn mixer Qp IFamp Qn IFamp Ip IFamp In IFamp Ip SC-filter In SC-filter Qp IFamp...
Page 46 Micrel, Inc. MICRF507 (11) Package Information and Recommended Landing Pattern 32-Pin QFN (ML) Note: 11. Package information is correct as of the publication date. For updates and most current information, go to www.micrel.com. Revision 2.2 October 2, 2013...
Page 47 (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.