SWRS128 June   2014 CC2541-Q1

PRODUCTION DATA.  

  1. 1Device Overview
    1. 1.1 Features
    2. 1.2 Applications
    3. 1.3 Description
    4. 1.4 Functional Block Diagram
  2. 2Revision History
  3. 3Terminal Configuration and Functions
    1. 3.1 Pin Diagram
    2. 3.2 Pin Descriptions
  4. 4Specifications
    1. 4.1  Absolute Maximum Ratings
    2. 4.2  Handling Ratings
    3. 4.3  Recommended Operating Conditions
    4. 4.4  Thermal Characteristics for RHA Package
    5. 4.5  Electrical Characteristics
    6. 4.6  General Characteristics
    7. 4.7  RF Receive Section
    8. 4.8  RF Transmit Section
    9. 4.9  32-MHz Crystal Oscillator
    10. 4.10 32.768-kHz Crystal Oscillator
    11. 4.11 32-kHz RC Oscillator
    12. 4.12 16-MHz RC Oscillator
    13. 4.13 RSSI Characteristics
    14. 4.14 Frequency Synthesizer Characteristics
    15. 4.15 Analog Temperature Sensor
    16. 4.16 Comparator Characteristics
    17. 4.17 ADC Characteristics
    18. 4.18 DC Characteristics
    19. 4.19 Control Input AC Characteristics
    20. 4.20 SPI AC Characteristics
    21. 4.21 Debug Interface AC Characteristics
    22. 4.22 Timer Inputs AC Characteristics
    23. 4.23 Typical Characteristics
  5. 5Detailed Description
    1. 5.1 Functional Block Diagram
    2. 5.2 Block Descriptions
      1. 5.2.1 CPU and Memory
      2. 5.2.2 Peripherals
  6. 6Application Information
    1. 6.1 Input/Output Matching
    2. 6.2 Crystal
    3. 6.3 On-Chip 1.8-V Voltage Regulator Decoupling
    4. 6.4 Power-Supply Decoupling and Filtering
  7. 7Device and Documentation Support
    1. 7.1 Documentation Support
      1. 7.1.1 Related Documentation
        1. 7.1.1.1 Additional Information
        2. 7.1.1.2 Texas Instruments Low-Power RF Website
        3. 7.1.1.3 Texas Instruments Low-Power RF Developer Network
        4. 7.1.1.4 Low-Power RF eNewsletter
    2. 7.2 Trademarks
    3. 7.3 Electrostatic Discharge Caution
    4. 7.4 Glossary
  8. 8Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

4 Specifications

4.1 Absolute Maximum Ratings(1)

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
Supply voltage All supply pins must have the same voltage –0.3 3.9 V
Voltage on any digital pin –0.3 VDD + 0.3 ≤ 3.9 V
Input RF level 10 dBm
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

4.2 Handling Ratings

MIN MAX UNIT
Tstg Storage temperature range –40 125 °C
VESD Electrostatic discharge (ESD) performance: Human Body Model (HBM), per AEC Q100-002(1) All pins –1 1 kV
All pins
(Excluding pins 25 and 26)		 –2 2
Charged Device Model (CDM), per AEC Q100-011 –500 500 V
(1) AEC Q100-002 indicates HBM stressing is done in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

4.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
Operating ambient temperature range, TA –40 105 °C
Operating supply voltage 2 3.6 V

4.4 Thermal Characteristics for RHA Package

NAME DESCRIPTION °C/W AIR FLOW (m/s)(1)
RΘJC Junction-to-case (top) 16.1 0.00
RΘJB Junction-to-board 5.5 0.00
RΘJA Junction-to-free air 30.6 0.00
PsiJT Junction-to-package top 0.2 0.00
PsiJB Junction-to-board 5.4 0.00
RθJC Junction-to-case (bottom) 1.0 0.00
(1) m/s = meters per second

4.5 Electrical Characteristics

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C and VDD = 3 V,
1 Mbps, GFSK, 250-kHz deviation, Bluetooth low energy mode, and 0.1% BER
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Icore Core current consumption RX mode, standard mode, no peripherals active, low MCU activity 18.3 mA
RX mode, high-gain mode, no peripherals active, low MCU activity 20.8
TX mode, –20 dBm output power, no peripherals active, low MCU activity 17.2
TX mode, 0 dBm output power, no peripherals active, low MCU activity 18.6
Power mode 1. Digital regulator on; 16-MHz RCOSC and 32-MHz crystal oscillator off; 32.768-kHz XOSC, POR, BOD and sleep timer active; RAM and register retention 270 µA
Power mode 2. Digital regulator off; 16-MHz RCOSC and 32-MHz crystal oscillator off; 32.768-kHz XOSC, POR, and sleep timer active; RAM and register retention 1
Power mode 3. Digital regulator off; no clocks; POR active; RAM and register retention 0.5
Low MCU activity: 32-MHz XOSC running. No radio or peripherals. Limited flash access, no RAM access. 6.7 mA
Iperi Peripheral current consumption (Adds to core current Icore for each peripheral unit activated) Timer 1. Timer running, 32-MHz XOSC used 90 μA
Timer 2. Timer running, 32-MHz XOSC used 90
Timer 3. Timer running, 32-MHz XOSC used 60
Timer 4. Timer running, 32-MHz XOSC used 70
Sleep timer, including 32.753-kHz RCOSC 0.6
ADC, when converting 1.2 mA

4.6 General Characteristics

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C and VDD = 3 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
WAKE-UP AND TIMING
Power mode 1 → Active Digital regulator on, 16-MHz RCOSC and 32-MHz crystal oscillator off. Start-up of 16-MHz RCOSC 4 μs
Power mode 2 or 3 → Active Digital regulator off, 16-MHz RCOSC and 32-MHz crystal oscillator off. Start-up of regulator and 16-MHz RCOSC 120 μs
Active → TX or RX Crystal ESR = 16 Ω. Initially running on 16-MHz RCOSC, with 32-MHz XOSC OFF 500 μs
With 32-MHz XOSC initially on 180 μs
RX/TX turnaround Proprietary auto mode 130 μs
BLE mode 150
RADIO PART
RF frequency range Programmable in 1-MHz steps 2379 2496 MHz
Data rate and modulation format 2 Mbps, GFSK, 500-kHz deviation
2 Mbps, GFSK, 320-kHz deviation
1 Mbps, GFSK, 250-kHz deviation
1 Mbps, GFSK, 160-kHz deviation
500 kbps, MSK
250 kbps, GFSK, 160-kHz deviation
250 kbps, MSK

4.7 RF Receive Section

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C, VDD = 3 V, fc = 2440 MHz
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
1 Mbps, GFSK, 250-kHz Deviation, Bluetooth low energy Mode, 0.1% BER
Receiver sensitivity(3)(4) High-gain mode –94 dBm
Standard mode –88
Saturation(4) BER < 0.1% 5 dBm
Co-channel rejection(4) Wanted signal –67 dBm –6 dB
In-band blocking rejection(4) ±1 MHz offset, 0.1% BER, wanted signal –67 dBm –2 dB
±2 MHz offset, 0.1% BER, wanted signal –67 dBm 26
±3 MHz offset, 0.1% BER, wanted signal –67 dBm 34
>6 MHz offset, 0.1% BER, wanted signal –67 dBm 33
Out-of-band blocking rejection(4) Minimum interferer level < 2 GHz (Wanted signal –67 dBm) –21 dBm
Minimum interferer level [2 GHz, 3 GHz] (Wanted signal –67 dBm) –27
Minimum interferer level > 3 GHz (Wanted signal –67 dBm) –8
Intermodulation(4) Minimum interferer level –36 dBm
Frequency error tolerance(1) Including both initial tolerance and drift. Sensitivity better than -67dBm, 250 byte payload. BER 0.1% –250 250 kHz
Symbol rate error tolerance(2) Maximum packet length. Sensitivity better than –67 dBm, 250 byte payload. BER 0.1% –80 80 ppm
ALL RATES/FORMATS
Spurious emission in RX. Conducted measurement f < 1 GHz –67 dBm
Spurious emission in RX. Conducted measurement f > 1 GHz –57 dBm
(1) Difference between center frequency of the received RF signal and local oscillator frequency
(2) Difference between incoming symbol rate and the internally generated symbol rate
(3) The receiver sensitivity setting is programmable using a TI BLE stack vendor-specific API command. The default value is standard mode.
(4) Results based on standard-gain mode.

4.8 RF Transmit Section

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C, VDD = 3 V and fc = 2440 MHz
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Output power Delivered to a single-ended 50-Ω load through a balun using maximum recommended output power setting 0 dBm
Delivered to a single-ended 50-Ω load through a balun using minimum recommended output power setting –20
Programmable output power range Delivered to a single-ended 50-Ω load through a balun using minimum recommended output power setting 20 dB
Spurious emission conducted measurement f < 1 GHz –52 dBm
f > 1 GHz –48 dBm
Suitable for systems targeting compliance with worldwide radio-frequency regulations ETSI EN 300 328 and EN 300 440 Class 2 (Europe), FCC CFR47 Part 15 (US), and ARIB STD-T66 (Japan)
Optimum load impedance Differential impedance as seen from the RF port (RF_P and RF_N) toward the antenna 70 +j30 Ω

Designs with antenna connectors that require conducted ETSI compliance at 64 MHz should insert an LC resonator in front of the antenna connector. Use a 1.6-nH inductor in parallel with a 1.8-pF capacitor. Connect both from the signal trace to a good RF ground.

4.9 32-MHz Crystal Oscillator

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C and VDD = 3 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Crystal frequency 32 MHz
Crystal frequency accuracy requirement(1) –40 40 ppm
ESR Equivalent series resistance 6 60 Ω
C0 Crystal shunt capacitance 1 7 pF
CL Crystal load capacitance 10 16 pF
Start-up time 0.25 ms
Power-down guard time The crystal oscillator must be in power down for a guard time before it is used again. This requirement is valid for all modes of operation. The need for power-down guard time can vary with crystal type and load. 3 ms
(1) Including aging and temperature dependency, as specified by [1]

4.10 32.768-kHz Crystal Oscillator

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C and VDD = 3 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Crystal frequency 32.768 kHz
Crystal frequency accuracy requirement(1) –40 40 ppm
ESR Equivalent series resistance 40 130 kΩ
C0 Crystal shunt capacitance 0.9 2 pF
CL Crystal load capacitance 12 16 pF
Start-up time 0.4 s

4.11 32-kHz RC Oscillator

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C and VDD = 3 V.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Calibrated frequency(1) 32.753 kHz
Frequency accuracy after calibration ±0.2%
Temperature coefficient(2) 0.4 %/°C
Supply-voltage coefficient(3) 3 %/V
Calibration time(4) 2 ms
(1) The calibrated 32-kHz RC oscillator frequency is the 32-MHz XTAL frequency divided by 977.
(2) Frequency drift when temperature changes after calibration
(3) Frequency drift when supply voltage changes after calibration
(4) When the 32-kHz RC oscillator is enabled, it is calibrated when a switch from the 16-MHz RC oscillator to the 32-MHz crystal oscillator is performed while SLEEPCMD.OSC32K_CALDIS is set to 0.

4.12 16-MHz RC Oscillator

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C and VDD = 3 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Frequency(1) 16 MHz
Uncalibrated frequency accuracy ±18%
Calibrated frequency accuracy ±0.6%
Start-up time 10 μs
Initial calibration time(2) 50 μs
(1) The calibrated 16-MHz RC oscillator frequency is the 32-MHz XTAL frequency divided by 2.
(2) When the 16-MHz RC oscillator is enabled, it is calibrated when a switch from the 16-MHz RC oscillator to the 32-MHz crystal oscillator is performed while SLEEPCMD.OSC_PD is set to 0.

4.13 RSSI Characteristics

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C and VDD = 3 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
2 Mbps, GFSK, 320-kHz Deviation, 0.1% BER and 2 Mbps, GFSK, 500-kHz Deviation, 0.1% BER
Useful RSSI range(1) Reduced gain by AGC algorithm 64 dB
High gain by AGC algorithm 64
RSSI offset(1) Reduced gain by AGC algorithm 79 dBm
High gain by AGC algorithm 99
Absolute uncalibrated accuracy(1) ±6 dB
Step size (LSB value) 1 dB
All Other Rates/Formats
Useful RSSI range(1) Standard mode 64 dB
High-gain mode 64
RSSI offset(1) Standard mode 98 dBm
High-gain mode 107
Absolute uncalibrated accuracy(1) ±3 dB
Step size (LSB value) 1 dB
(1) Assuming CC2541-Q1 EM reference design. Other RF designs give an offset from the reported value.

4.14 Frequency Synthesizer Characteristics

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C, VDD = 3 V and fc = 2440 MHz
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Phase noise, unmodulated carrier At ±1-MHz offset from carrier –109 dBc/Hz
At ±3-MHz offset from carrier –112
At ±5-MHz offset from carrier –119

4.15 Analog Temperature Sensor

Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C and VDD = 3 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Output Measured using integrated ADC, internal band-gap voltage reference, and maximum resolution 1480 12-bit
Temperature coefficient 4.5 / 1°C
Voltage coefficient 1 0.1 V
Initial accuracy without calibration ±10 °C
Accuracy using 1-point calibration ±5 °C
Current consumption when enabled 0.5 mA

4.16 Comparator Characteristics

TA = 25°C, VDD = 3 V. All measurement results are obtained using the CC2541-Q1 reference designs, post-calibration.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Common-mode maximum voltage VDD V
Common-mode minimum voltage –0.3
Input offset voltage 1 mV
Offset vs temperature 16 µV/°C
Offset vs operating voltage 4 mV/V
Supply current 230 nA
Hysteresis 0.15 mV

4.17 ADC Characteristics

TA = 25°C and VDD = 3 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Input voltage VDD is voltage on AVDD5 pin 0 VDD V
External reference voltage VDD is voltage on AVDD5 pin 0 VDD V
External reference voltage differential VDD is voltage on AVDD5 pin 0 VDD V
Input resistance, signal Simulated using 4-MHz clock speed 197 kΩ
Full-scale signal(1) Peak-to-peak, defines 0 dBFS 2.97 V
ENOB(1) Effective number of bits Single-ended input, 7-bit setting 5.7 bits
Single-ended input, 9-bit setting 7.5
Single-ended input, 10-bit setting 9.3
Single-ended input, 12-bit setting 10.3
Differential input, 7-bit setting 6.5
Differential input, 9-bit setting 8.3
Differential input, 10-bit setting 10
Differential input, 12-bit setting 11.5
10-bit setting, clocked by RCOSC 9.7
12-bit setting, clocked by RCOSC 10.9
Useful power bandwidth 7-bit setting, both single and differential 0–20 kHz
THD Total harmonic distortion Single ended input, 12-bit setting, –6 dBFS(1) –75.2 dB
Differential input, 12-bit setting, –6 dBFS(1) –86.6
Signal to nonharmonic ratio Single-ended input, 12-bit setting(1) 70.2 dB
Differential input, 12-bit setting(1) 79.3
Single-ended input, 12-bit setting, –6 dBFS(1) 78.8
Differential input, 12-bit setting, –6 dBFS(1) 88.9
CMRR Common-mode rejection ratio Differential input, 12-bit setting, 1-kHz sine
(0 dBFS), limited by ADC resolution		 >84 dB
Crosstalk Single ended input, 12-bit setting, 1-kHz sine
(0 dBFS), limited by ADC resolution		 >84 dB
Offset Midscale –3 mV
Gain error 0.68%
DNL Differential nonlinearity 12-bit setting, mean(1) 0.05 LSB
12-bit setting, maximum(1) 0.9
INL Integral nonlinearity 12-bit setting, mean(1) 4.6 LSB
12-bit setting, maximum(1) 13.3
12-bit setting, mean, clocked by RCOSC 10
12-bit setting, max, clocked by RCOSC 29
SINAD
(–THD+N) 		Signal-to-noise-and-distortion Single ended input, 7-bit setting(1) 35.4 dB
Single ended input, 9-bit setting(1) 46.8
Single ended input, 10-bit setting(1) 57.5
Single ended input, 12-bit setting(1) 66.6
Differential input, 7-bit setting(1) 40.7
Differential input, 9-bit setting(1) 51.6
Differential input, 10-bit setting(1) 61.8
Differential input, 12-bit setting(1) 70.8
Conversion time 7-bit setting 20 μs
9-bit setting 36
10-bit setting 68
12-bit setting 132
Power consumption 1.2 mA
Internal reference VDD coefficient 4 mV/V
Internal reference temperature coefficient 0.4 mV/10°C
Internal reference voltage 1.24 V
(1) Measured with 300-Hz sine-wave input and VDD as reference.

4.18 DC Characteristics

TA = 25°C, VDD = 3 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Logic-0 input voltage 0.5 V
Logic-1 input voltage 2.4 V
Logic-0 input current Input equals 0 V –50 50 nA
Logic-1 input current Input equals VDD –50 50 nA
I/O-pin pullup and pulldown resistors 20 kΩ
Logic-0 output voltage, 4- mA pins Output load 4 mA 0.5 V
Logic-1 output voltage, 4-mA pins Output load 4 mA 2.5 V
Logic-0 output voltage, 20- mA pins Output load 20 mA 0.5 V
Logic-1 output voltage, 20-mA pins Output load 20 mA 2.5 V

4.19 Control Input AC Characteristics

TA = –40°C to 105°C, VDD = 2 V to 3.6 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
System clock, fSYSCLK
tSYSCLK = 1/ fSYSCLK		 The undivided system clock is 32 MHz when crystal oscillator is used. The undivided system clock is 16 MHz when calibrated 16-MHz RC oscillator is used. 16 32 MHz
RESET_N low duration See item 1, Figure 4-1. This is the shortest pulse that is recognized as a complete reset pin request. Note that shorter pulses may be recognized but do not lead to complete reset of all modules within the chip. 1 µs
Interrupt pulse duration See item 2, Figure 4-1.This is the shortest pulse that is recognized as an interrupt request. 20 ns
T0299-01_WRS075.gifFigure 4-1 Control Input AC Characteristics

4.20 SPI AC Characteristics

TA = –40°C to 105°C, VDD = 2 V to 3.6 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
t1 SCK period Master, RX and TX 250 ns
Slave, RX and TX 250
SCK duty cycle Master 50%
t2 SSN low to SCK Master 63 ns
Slave 63
t3 SCK to SSN high Master 63 ns
Slave 63
t4 MOSI early out Master, load = 10 pF 7 ns
t5 MOSI late out Master, load = 10 pF 10 ns
t6 MISO setup Master 90 ns
t7 MISO hold Master 10 ns
SCK duty cycle Slave 50% ns
t10 MOSI setup Slave 35 ns
t11 MOSI hold Slave 10 ns
t9 MISO late out Slave, load = 10 pF 95 ns
Operating frequency Master, TX only 8 MHz
Master, RX and TX 4
Slave, RX only 8
Slave, RX and TX 4
T0478-01_WRS086.gifFigure 4-2 SPI Master AC Characteristics
T0479-01_WRS086.gifFigure 4-3 SPI Slave AC Characteristics

4.21 Debug Interface AC Characteristics

TA = –40°C to 105°C, VDD = 2 V to 3.6 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
fclk_dbg Debug clock frequency (see Figure 4-4) 12 MHz
t1 Allowed high pulse on clock (see Figure 4-4) 35 ns
t2 Allowed low pulse on clock (see Figure 4-4) 35 ns
t3 EXT_RESET_N low to first falling edge on debug clock (see Figure 4-6) 167 ns
t4 Falling edge on clock to EXT_RESET_N high (see Figure 4-6) 83 ns
t5 EXT_RESET_N high to first debug command (see Figure 4-6) 83 ns
t6 Debug data setup (see Figure 4-5) 2 ns
t7 Debug data hold (see Figure 4-5) 4 ns
t8 Clock-to-data delay (see Figure 4-5) Load = 10 pF 30 ns
T0436-01_WRS081.gifFigure 4-4 Debug Clock – Basic Timing
T0437-01_WRS081.gifFigure 4-5 Debug Enable Timing
Dsetup_tim_wrs110.gifFigure 4-6 Data Setup and Hold Timing

4.22 Timer Inputs AC Characteristics

TA = –40°C to 105°C, VDD = 2 V to 3.6 V
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Input capture pulse duration Synchronizers determine the shortest input pulse that can be recognized. The synchronizers operate at the current system clock rate (16 MHz or 32 MHz). 1.5 tSYSCLK

4.23 Typical Characteristics

D003_SWRS128.gif
Figure 4-7 RX Current vs Temperature
D006_SWRS128.gif
Figure 4-9 RX Sensitivity vs Temperature
D002_SWRS128.gif
Figure 4-11 RX Current vs Supply Voltage
G007_SWRS128.png
1-Mbps GFSK 250-kHz Standard Gain Setting
TA = 25°C
Figure 4-13 RX Sensitivity vs Supply Voltage
G009_SWRS128.png
1-Mbps GFSK 250-kHz Standard Gain Setting
TA = 25°C
Vcc = 3 V
Figure 4-15 RX Sensitivity vs Frequency
D005_SWRS128.gif
Figure 4-8 TX Current vs Temperature
D001_SWRS128.gif
Figure 4-10 TX Power vs Temperature
D004_SWRS128.gif
Figure 4-12 TX Current vs Supply Voltage
G008_SWRS128.png
TX Power Setting = 0 dBm
TA = 25°C
Figure 4-14 TX Power vs Supply Voltage
G010_SWRS128.png
TX Power Setting = 0 dBm
TA = 25°C
Vcc = 3 V
Figure 4-16 TX Power vs Frequency

Table 4-1 Output Power(1)(2)

TX POWER Setting Typical Output Power (dBm)
0xE1 0
0xD1 –2
0xC1 –4
0xB1 –6
0xA1 –8
0x91 –10
0x81 –12
0x71 –14
0x61 –16
0x51 –18
0x41 –20
(1) Measured on Texas Instruments CC2541-Q1 EM reference design with TA = 25°C, VDD = 3 V and fc = 2440 MHz. See SWRU191 for recommended register settings.
(2) 1 Mbsp, GFSK, 250-kHz deviation, Bluetooth low energy mode, 1% BER