CMOSTEK CMT2219A: 300 – 960 MHz OOK/(G)FSK Receiver
An ultra low power, high performance RF receiver for wireless applications.
Features
- Optional Configuration Schemes: On-Line Configuration via Registers or Off-Line Configuration via EEPROM.
- Frequency Range: 300 to 960 MHz.
- Supports OOK, FSK, and GFSK Demodulation.
- Symbol Rate: 1.2 to 100 ksps.
- Sensitivity: -109 dBm at 9.6 ksps, 0.1% BER, FRF = 868 MHz.
- 4-wire SPI Interface.
- Direct, Buffer, and Packet Mode Supported.
- Configurable Data Handler and 32-Byte FIFO.
- Manchester Decoding and Data De-Whitening.
- Supply Voltage: 1.8 V to 3.6 V.
- Low Power Consumption: 5.8 mA (typical).
- Low Sleep Current: 60 nA (Sleep Timer Off), 440 nA (Sleep Timer On).
- RoHS Compliant.
- 16-pin QFN 3x3 Package.
Description
The CMT2219A is an ultra low power, high performance OOK and (G)FSK RF receiver designed for various 300 to 960 MHz wireless applications. It is part of the CMOSTEK NextGenRF™ family. The device features a fully integrated, low-IF receiver architecture, minimizing external components and susceptibility to powerline interference. It includes a VCO and a low noise fractional-N PLL with a high output frequency resolution. All analog blocks are calibrated upon Power-on Reset (POR) for optimal performance across temperature and supply voltage variations. The baseband filtering and demodulation are handled by a digital demodulator. The device supports packet handling, a 32-byte FIFO, Manchester decoding, and data de-whitening. It can output demodulated data, sync clock, power-on reset, system clock, and two configurable interrupts. The CMT2219A receiver, when paired with the CMT211xA transmitter, enables a robust RF link.
Applications
- Low-Cost Consumer Electronics Applications.
- Home and Building Automation.
- Infrared Receiver Replacements.
- Industrial Monitoring and Controls.
- Remote Automated Meter Reading.
- Remote Lighting Control Systems.
- Wireless Alarm and Security Systems.
- Remote Keyless Entry (RKE).
Typical Application Schematic
The typical application schematic shows the CMT2219A integrated into a circuit. Key components include the CMT2219A receiver (U1), an external crystal oscillator (X1), inductors (L1, L2), capacitors (C0, C1, C2, C3), and a microcontroller (U2). An antenna is connected via the RFIN pin. A connector (J1) is shown for EEPROM programming, which is essential during development and manufacturing. The schematic highlights the connections for the SPI interface (CSB, SDA, SCL, FCSB) and general-purpose outputs (GPO1-GPO4).
Layout guidelines suggest using a continuous ground plane, grounding vias near GND pins, avoiding long transmission lines, and placing decoupling capacitors close to the IC.
Electrical Characteristics
The device operates with a supply voltage (VDD) between 1.8 V and 3.6 V. Typical operating conditions include an ambient temperature of 25°C and an RF frequency of 433.92 MHz. Sensitivity is measured at -109 dBm (FSK, 9.6 ksps, 0.1% BER). Absolute maximum ratings define the limits beyond which permanent damage may occur, such as a supply voltage range of -0.3 V to 3.6 V and a junction temperature up to 125°C. The device is sensitive to Electrostatic Discharge (ESD), with an HBM rating of < 2 kV, requiring handling at ESD-protected workstations.
Recommended Operation Conditions
| Parameter | Symbol | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| Operation Voltage Supply | VDD | 1.8 | 3.6 | V | ||
| Operation Temperature | TOP | -40 | 85 | °C | ||
| Supply Voltage Slew Rate | 1 | mV/us |
Absolute Maximum Ratings
| Parameter | Symbol | Conditions | Min | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | VDD | -0.3 | 3.6 | V | |
| Interface Voltage | VIN | -0.3 | VDD + 0.3 | V | |
| Junction Temperature | TJ | -40 | 125 | °C | |
| Storage Temperature | TSTG | -50 | 150 | °C | |
| Soldering Temperature | TSDR | Lasts at least 30 seconds | 255 | °C | |
| ESD Rating [2] | Human Body Model (HBM) | -2 | 2 | kV | |
| Latch-up Current | @ 85 °C | -100 | 100 | mA |
Note: The CMT2219A has an ESD rating of < 2 kV HBM. Handle with care at ESD-protected workstations.
Receiver Specifications
The CMT2219A offers a frequency range of 300 to 480 MHz. It supports OOK symbol rates from 0.1 to 40 ksps and FSK/GFSK symbol rates from 0.1 to 100 ksps. Sensitivity figures are provided for various frequencies and modulation types, reaching -109 dBm for FSK at 9.6 ksps. The device exhibits low working currents (around 3.5-5.9 mA) and very low sleep currents (60-440 nA). Other specifications include frequency resolution, synthesizer settle time, blocking immunity, and image rejection ratio.
| Parameter | Symbol | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| Frequency Range | FRF | 300 | 480 | MHz | ||
| Symbol Rate | SR | OOK | 0.1 | 40 | ksps | |
| FSK | 0.1 | 100 | ksps | |||
| Deviation | FDEV | FSK | 1 | 200 | kHz | |
| Gaussian Filter BT | BT | 0.5 | ||||
| Sensitivity (OOK) | S315-OOK | 315 MHz, SR = 1 ksps, | -114 | dBm | ||
| S433.92-OOK | 433.92 MHz, SR = 1 ksps, | -113 | dBm | |||
| S868-OOK | 868 MHz, SR = 1 ksps, | -110 | dBm | |||
| S915-OOK | 915 MHz, SR = 1 ksps, | -109 | dBm | |||
| Sensitivity (FSK) | S315-FSK | 315 MHz, SR = 9.6 ksps, FDEV = 19.2 kHz | -112 | dBm | ||
| S433.92-FSK | 433.92 MHz, SR = 9.6 ksps, FDEV = 19.2 kHz | -111 | dBm | |||
| S868-FSK | 868 MHz, SR = 9.6 ksps, FDEV = 19.2 kHz | -109 | dBm | |||
| S915-FSK | 915 MHz, SR = 9.6 ksps, FDEV = 19.2 kHz | -109 | dBm | |||
| Saturation Input Signal Level | PLVL | 10 | dBm | |||
| OOK Working Current | IDD-OOK | 315 MHz, 50%, OOK | 3.5 | mA | ||
| 433.92 MHz, 50%, OOK | 3.8 | mA | ||||
| 868 MHz, 50%, OOK | 5.2 | mA | ||||
| 915 MHz, 50%, OOK | 5.4 | mA | ||||
| FSK Working Current | IDD-FSK | 315 MHz, FSK | 4.0 | mA | ||
| 433.92 MHz, FSK | 4.3 | mA | ||||
| 868 MHz, FSK | 5.7 | mA | ||||
| 915 MHz, FSK | 5.9 | mA | ||||
| Sleep Current | ISLEEP | When sleep timer is on | 440 | nA | ||
| When sleep timer is off | 60 | nA | ||||
| Frequency Resolution | FRES | 24.8 | Hz | |||
| Frequency Synthesizer Settle Time | TLOCK | From XOSC settled | 150 | us | ||
| Blocking Immunity | BI | SR = 1 ksps, ±1 MHz offset, CW interference | 52 | dB | ||
| SR = 1 ksps, ±2 MHz offset, CW interference | 74 | dB | ||||
| SR = 1 ksps, ±10 MHz offset, CW interference | 75 | dB | ||||
| Image Rejection Ratio | IMR | IF = 280 kHz | 35 | dB | ||
| Input 3rd Order Intercept Point | IIP3 | Two tone test at 1 MHz and 2 MHz offset frequency. Maximum system gain settings | -25 | dBm | ||
| Receiver Bandwidth | BW | 50 | 500 | kHz | ||
| Receiver Start-up Time | TSTART-UP | From power up to receive, in Always Receive Mode | 4.3 | ms | ||
| Receiver Wake-up Time | TWAKE-UP | From sleep to receive, in Duty-Cycle Receive Mode | 0.61 | ms |
Crystal Oscillator
The device utilizes a 26 MHz crystal oscillator as a reference clock for the PLL frequency synthesizer and system clock. Appropriate loading capacitors (C2, C3) are required, determined by the crystal's specified total load capacitance (CL). The crystal's Equivalent Series Resistance (ESR) should be within specifications for reliable start-up. An external clock source can also be used, requiring a peak-to-peak amplitude of 300 mV to 700 mV.
| Parameter | Symbol | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| Crystal Frequency[1] | FXTAL | 26 | 26 | 26 | MHz | |
| Crystal Tolerance[2] | ±20 | ppm | ||||
| Load Capacitance | CLOAD | 10 | 15 | 20 | pF | |
| Crystal ESR | Rm | 60 | Ω | |||
| XTAL Startup Time[3] | tXTAL | 400 | us |
Notes: [1] External clock input requires a coupling capacitor. [2] Total tolerance includes initial, loading, aging, and temperature dependence. [3] Crystal dependent.
LPOSC (Low Power Oscillator)
An internal 1 kHz low power oscillator is integrated for the sleep timer. It is automatically calibrated during the Power-Up (PUP) state and periodically thereafter, maintaining frequency tolerance within ±1%. The sleep time can be configured from 3 ms up to over 37 hours.
| Parameter | Symbol | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| Calibrated Frequency[1] | FLPOSC | 1 | kHz | |||
| Frequency Accuracy | After calibration | 1 | % | |||
| Temperature Coefficient[2] | -0.02 | %/°C | ||||
| Supply Voltage Coefficient[3] | +0.5 | %/V | ||||
| Initial Calibration Time | tLPOSC-CAL | 4 | ms |
Notes: [1] LPOSC is calibrated during PUP and periodically. [2] Frequency drift with temperature. [3] Frequency drift with supply voltage.
Pin Descriptions
The CMT2219A is available in a 16-pin QFN 3x3 package. Key pins include:
- CSB: SPI chip select input (active low).
- SDA: SPI data input/output.
- SCL: SPI clock input.
- FCSB: SPI FIFO select input (active low).
- RFIN: RF signal input to the LNA.
- VDD/GND: Power supply and ground.
- XIN/XOUT: Crystal oscillator pins.
- GPO1-GPO4: General purpose outputs, configurable for various functions like interrupts, clock output, or data output.
- VCON/VCOP: VCO related pins, connected to an external inductor.
| Pin Number | Name | I/O | Descriptions |
|---|---|---|---|
| 1 | CSB | I | 4-wire SPI chip select input, active low |
| 2 | SDA | IO | 4-wire SPI data input and output |
| 3 | SCL | I | 4-wire SPI clock input |
| 4 | FCSB | I | 4-wire SPI FIFO select input, active low. Internally pulled high, leave floating when programming the EEPROM |
| 5 | GPO4 | O | General purpose output, options are: DOUT (Default), INT1, INT2 and DCLK |
| 6 | GPO3 | O | General purpose output, options are: CLKO (Default), INT1, INT2 and DOUT |
| 7 | XOUT | O | Crystal oscillator output |
| 8 | XIN | I | Crystal oscillator input or external reference clock input |
| 9 | GPO2 | O | General purpose output, options are: INT1 (Default), INT2 and DCLK |
| 10 | GPO1 | O | General purpose output, options are: nRSTO (Default), INT1, INT2 and DOUT |
| 11 | VCOP | IO | VCO tank, connected to an external inductor |
| 12 | VCON | IO | VCO tank, connected to an external inductor |
| 13, 15 | GND | I | Ground |
| 14 | RFIN | I | RF signal input to the LNA |
| 16 | VDD | I | Power supply input |
Typical Performance Characteristics
Performance graphs illustrate key characteristics:
- Current vs. Supply Voltage: Current consumption increases with supply voltage.
- Current vs. Temperature: Current consumption shows a slight increase with temperature.
- Sensitivity vs. Supply Voltage: Sensitivity degrades (becomes more negative) as supply voltage increases.
- Sensitivity vs. Temperature: Sensitivity degrades as temperature increases.
- Sensitivity vs. Symbol Rate: Sensitivity decreases as the symbol rate increases.
- Sensitivity vs. BER: Sensitivity decreases as the Bit Error Rate (BER) increases.
Functional Descriptions
Overview
The CMT2219A employs a low-IF receiver architecture. Its integrated RF front-end includes an LNA, I/Q mixer, and a wide-band power detector. Automatic Gain Control (AGC) ensures optimal performance across varying signal conditions. The IF filter provides image rejection, and the RSSI generator measures signal strength. An 8-bit SAR ADC digitizes the RSSI. The frequency synthesizer uses a VCO and a fractional-N PLL. The LPOSC provides a low-power clock for the sleep timer. The device supports OOK and (G)FSK demodulation with configurable symbol rates and frequencies. It features a 4-wire SPI interface for configuration and control by an external MCU. Configurations can be loaded via EEPROM or directly through registers using the RFPDK tool.
Modulation, Frequency and Symbol Rate
The CMT2219A supports OOK demodulation with symbol rates from 0.1 to 40 ksps and (G)FSK demodulation from 0.1 to 100 ksps. It covers the frequency range of 300 to 960 MHz, including common ISM bands like 315, 433.92, 868, and 915 MHz. The frequency synthesizer offers a resolution of 24.8 Hz.
| Parameter | Value | Unit |
|---|---|---|
| Demodulation | OOK/(G)FSK | |
| Frequency | 300 to 960 | MHz |
| Frequency Resolution | 24.8 | Hz |
| Symbol Rate | OOK: 0.1 to 40 FSK: 0.1 to 100 (G)FSK: 0.1 to 100 |
ksps |
Embedded EEPROM and RFPDK
The CMOSTEK RF Products Development Kit (RFPDK) is a PC application used to configure CMOSTEK NextGenRF™ products. Users connect a USB programmer to the PC and device, set parameters in RFPDK, and burn configurations into the device's EEPROM. Configurations can be saved to a list or exported as a HEX file for mass production or MCU programming. The figure shows the connection for accessing the EEPROM.
All Configurable Options
Beyond demodulation, frequency, and symbol rate, numerous options allow device customization. The RFPDK offers 'Basic Mode' for simple configurations and 'Advanced Mode' for deeper control. Detailed parameter descriptions are available in the "AN138 CMT2219A Configuration Guideline" document.
Internal Blocks Description
- RF Front-end and AGC: Features an LNA, I/Q mixer, and power detector. AGC loop optimizes gain for linearity, selectivity, and sensitivity.
- IF Filter: Integrated 3rd-order band-pass filter with over 35 dB image rejection.
- RSSI: Multistage I/Q Log amplifiers produce DC voltages proportional to signal level, providing up to 66 dB dynamic range. Includes DC-offset cancellation.
- SAR ADC: An 8-bit ADC digitizes RSSI for FSK demodulator control or OOK threshold comparison.
- Crystal Oscillator: Provides a 26 MHz reference clock. Requires external loading capacitors and has an ESR specification. An external clock source can be used.
- Frequency Synthesizer: Generates LO frequency using a VCO and fractional-N PLL, offering fine frequency resolution.
- LPOSC: An internal 1 kHz oscillator for the sleep timer, automatically calibrated for accuracy.
- OOK Demodulation: Compares RSSI to a threshold, supporting 'Fixed TH' and 'Peak TH' methods.
- (G)FSK Demodulation: Supports high-performance demodulation with configurable symbol rates and deviations. The modulation index is calculated as (Deviation x 2) / Symbol Rate.
SPI Interface
A 4-wire SPI interface facilitates communication between the MCU and the CMT2219A. The active-low CSB signal indicates register access, while FCSB indicates FIFO access. Data is transferred MSB-first on the falling edge of SCL and captured on the rising edge. The SDA pin is bi-directional.
Register Read & Write Operation
Register access involves sending an r/w bit followed by a 7-bit address. CSB must be held low during the operation. Timing diagrams illustrate the sequence.
FIFO Read Operation
Reading the 32-byte FIFO involves using the FCSB signal. The internal read pointer increments automatically. Timing diagrams show the required sequence for reading FIFO data.
Operation States, Timing and Power
Power-Up Sequence
Upon power-on, the device goes through a sequence including POR release (approx. 0.5 ms), crystal stabilization (2.5 ms), and internal block calibrations (6.5 ms), before entering the SLEEP state. The total power-up time is about 9.5 ms.
Operating States
The CMT2219A supports six operating states: PUP (Power-Up), SLEEP, STBY (Standby), TUNE, RX (Receive), and EEPROM. Each state activates specific blocks for power efficiency. The SLEEP state offers minimal power consumption (60 nA without sleep timer, 440 nA with). STBY consumes ~520 uA, TUNE ~2 mA, and RX varies based on frequency and modulation. State transitions are controlled via SPI commands.
The device operates as a state machine, transitioning between SLEEP, STBY, TUNE, and RX states. The timing and power consumption for a typical receive cycle from SLEEP to RX are illustrated, showing the sequence of operations and current draw.
GPOs and Interrupts
Four General Purpose Outputs (GPOs) are available for flexible signaling, including interrupts (INT1, INT2), clock outputs (CLKO), reset (nRSTO), and data output (DOUT). Various interrupt sources (e.g., RSSI valid, preamble detected, sync word detected, packet received) can be configured to trigger these GPOs. Interrupts can be enabled/disabled and cleared via specific registers. The INTCTL registers manage interrupt mapping and status flags.
Data Handling
Data is managed via a packet handler and a 32-byte FIFO, supporting three modes: Direct, Buffer, and Packet.
- Direct Mode: Data is output directly to the MCU via DOUT, with an optional sync clock on DCLK. Preamble and sync word detection are optional.
- Buffer Mode: Data is shifted into the FIFO after a valid sync word. The MCU reads the FIFO via SPI. Sync word detection is mandatory.
- Packet Mode: Data is first decoded by the packet handler, then stored in the FIFO. Supports fixed-length and variable-length packets, including optional Node ID and CRC checks.
Packet structures can be fixed-length (payload up to 32 bytes) or variable-length (with a length byte indicating payload size). The packet handler offers decoding and validation options to reduce MCU workload.
User Registers
The CMT2219A features two banks of user registers: Configuration Bank (addresses 0x00-0x3D) for device feature configuration, and Control Bank (registers 0x3F-0x4F) for controlling GPO/interrupts, reading RSSI, enabling functions, setting operation modes, and performing soft resets. Configurations are typically loaded via SPI from an external MCU using parameters generated by the RFPDK.
Configuration Bank
Includes Sync Word registers (SYNC_A to SYNC_D) which can be programmed via RFPDK or directly by the MCU.
Control Bank
Provides registers like INT_EN (interrupt enable), IO_SEL (GPO signal selection), INTCTL_A/B/C/D (interrupt control and status), RSSI (real-time RSSI value), FUNC_EN (function enable), OP_CTRL (operating state control), and SOFTRST (soft reset).
Ordering Information
The CMT2219A is available as part number CMT2219A-EQR. It is supplied in a QFN16 (3x3) package, Tape & Reel option, suitable for industrial operating conditions (-40 to 85°C) and a voltage range of 1.8 to 3.6 V. The Minimum Order Quantity (MOQ) is 5,000 pieces.
| Part Number | Descriptions | Package Type | Package Option | Operating Condition | MOQ / Multiple |
|---|---|---|---|---|---|
| CMT2219A-EQR[1] | 300 – 960 MHz OOK/(G)FSK Stand-Alone RF Receiver | QFN16 (3x3) | Tape & Reel | 1.8 to 3.6 V, -40 to 85 °C |
5,000 |
Note: [1] 'E' denotes extended industrial grade, 'Q' denotes QFN16 package, 'R' denotes tape and reel.
Package Outline
The device is supplied in a 16-pin QFN 3x3 package. Detailed dimensions are provided in the table below.
| Symbol | Size (millimeters) | |
|---|---|---|
| Min | Max | |
| A | 0.7 | 0.8 |
| A1 | 0.05 | |
| b | 0.18 | 0.30 |
| c | 0.18 | 0.25 |
| D | 2.90 | 3.10 |
| D2 | 1.55 | 1.75 |
| e | 0.50 BSC | |
| E | 2.90 | 3.10 |
| E2 | 1.55 | 1.75 |
| L | 0.35 | 0.45 |
Top Marking
The top marking on the CMT2219A includes the part number '219A' and date code information ('YWW', where Y is the mold year digit and WW is the workweek). A pin 1 indicator (circle) is also present.
| Mark Method | Laser |
|---|---|
| Pin 1 Mark | Circle's diameter = 0.3 mm |
| Font Size | 0.5 mm, right-justified |
| Line 1 Marking | 219A, represents part number CMT2219A |
| Line 2 Marking | ①②③④ Internal tracking number |
| Line 3 Marking | Date code assigned by the assembly house. Y represents the last digit of the mold year and WW represents the workweek |
Other Documentations
Related documentation includes:
- AN133: CMT2117A/2217(9)A One-Way RF Link Development Kits User's Guide.
- AN137: CMT2219A Schematic and PCB Layout Design Guideline.
- AN138: CMT2219A Configuration Guideline.
Contact Information
CMOSTEK Microelectronics Co., Ltd.
Room 202, Honghai Building, Qianhai Road, Nanshan District
Shenzhen, Guangdong, China PRC
Zip Code: 518000
Tel: 0755 - 83235017
Fax: 0755 - 82761326
Sales: sales@cmostek.com
Technical support: support@cmostek.com
Website: www.cmostek.com
Copyright © CMOSTEK Microelectronics Co., Ltd. All rights reserved.
