Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsMAX35101EHJ+

General Description

The MAX35101 is a time-to-digital converter with built-in

amplifier and comparator targeted as a complete analog

front-end (AFE) solution for the ultrasonic heat meter and

flow meter markets.

With a time measurement accuracy of 20ps and auto-

matic differential time-of-flight (TOF) measurement, this

device makes for simplified computation of liquid flow.

Early edge detection ensures measurements are made

with consistent wave patterns to greatly improve accuracy

and eliminate erroneous measurements.

Multihit capability with stop-enable windowing allows

the device to be fine-tuned for the application. Internal

analog switches, an autozero amplifier/comparator, real-

time clock (RTC), and programmable receiver sensitivity

provide the analog interface and control for a minimal

electrical bill of material solution. The RTC provides an

event timing mode that is configurable and runs cyclic

algorithms to minimize microprocessor interactivity and

increase battery life.

Built-in arithmetic logic unit provides TOF difference mea-

surements. A programmable receiver hit accumulator can

be utilized to minimize the host microprocessor access

and thus minimize current consumption.

For temperature measurement, the MAX35101 supports

up to four (4) 2-wire PT1000/500 platinum resistive tem-

perature detectors (RTD).

A simple 4-wire SPI interface allows any microcon-

troller to effectively configure the device for its intended

measurement.

On-board 8KB user flash allows the MAX35101 to be

nonvolatile-configurable and provide nonvolatile energy

use data to be logged. Configuration can be recalled any-

time with a SPI command.

Applications

● Ultrasonic Heat Meters

● Ultrasonic Water Meters

● Ultrasonic Gas Meters

Features and Benets

● Early Edge Detect Ultrasonic Time-of-Flight

• Time-to-Digital Accuracy Down to 20ps

• Measurement Range Up to 8ms

• Multihit Capability

• Early Edge Detect to Provide Advanced Accuracy

• Programmable TOF Hit Accumulator

• Two Channels: Single-Stop Channel

• Stop-Enable Windowing with Edge Trigger Select

• Built-In Pulse Launcher with Programmable

Frequency

• Autozero Receiver Comparator

• Programmable Acoustic Recovery Sensitivity

• Automatic Two-Pulse Algorithm for Differential TOF

Measurement

● Temperature Measurement

• Up to Four (4) 2-Wire Sensors

• PT1000 and PT500 RTD Support

● Event Timing Mode

• Allows Automatic Measurement Cycles

• Minimizes Microcontroller Interactivity to Reduce

Power Consumption

● Tamper Detection

• Single Input Pin Detects Tamper and Generates

Processor Interrupt

● Power Consumption

• 2.3V to 3.6V Single-Supply Operation

● General

• 8KB of Nonvolatile Flash Memory for Data Logging

• Built-in Real Time Clock for Time of Day

Monitoring

• 4MHz Oscillator Can Be a Ceramic Device to

Lower System Cost

• Small, 5mm x 5mm, 32-Pin TQFP Package

• 4-Wire SPI Interface

• -40°C to +85°C Operation

Ordering Information appears at end of data sheet.

MAX35101 Time-to-Digital Converter with Analog Front-End

19-6830; Rev 0; 2/14

EVALUATION KIT AVAILABLE

Summary of content (66 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX35101 Time-to-Digital Converter with Analog Front-End General Description The MAX35101 is a time-to-digital converter with built-in amplifier and comparator targeted as a complete analog front-end (AFE) solution for the ultrasonic heat meter and flow meter markets. With a time measurement accuracy of 20ps and automatic differential time-of-flight (TOF) measurement, this device makes for simplified computation of liquid flow.
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MAX35101 Time-to-Digital Converter with Analog Front-End Absolute Maximum Ratings (Voltages relative to ground.) Voltage Range on VCC Pins.................................-0.5V to +4.0V Voltage Range on All Other Pins (not to exceed 4.0V).............................. -0.5V to (VCC + 0.5V) Continuous Power Dissipation (TA = +70°C) TQFP (derate 27.80mW/ºC above +70°C)............2222.20mW Operating Temperature Range............................ -40°C to +85°C Junction Temperature...........................
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MAX35101 Time-to-Digital Converter with Analog Front-End Electrical Characteristics (continued) (VCC = 2.3V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = 3.0V and TA = +25°C.) (Notes 2, 3) PARAMETER Output Voltage High (Launch_UP, Launch_DN) SYMBOL VOHLAUCH Output Voltage Low (WDO, INT, DOUT, CMP_OUT/UP_DN) VOL Pulldown Resistance (TC) RTC Input Voltage Low (TC) CONDITIONS MIN TYP VCC = 3.3V, IOUT = -50mA 2.8 3.
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MAX35101 Time-to-Digital Converter with Analog Front-End Electrical Characteristics (continued) (VCC = 2.3V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = 3.0V and TA = +25°C.
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MAX35101 Time-to-Digital Converter with Analog Front-End Recommended External Crystal Characteristics PARAMETER SYMBOL 32kHz Nominal Frequency CONDITIONS MIN f32K 32kHz Frequency Tolerance Δf32K/f32K 32kHz Load Capacitance CL32K 32kHz Series Resistance RS32K 4MHz Crystal Nominal Frequency Δf4M/f4M 4MHz Crystal Load Capacitance CL4M 4MHz Crystal Series Resistance RS4M MAX 32.768 TA = +25°C +20 12.5 4.000 +30 12.0 120 TA = +25°C Ω MHz -0.5 4MHz Ceramic Load Capacitance ppm pF 4.
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MAX35101 Time-to-Digital Converter with Analog Front-End Timing Diagrams (continued) Figure 2 tCC CE tCLK tCWH tR tF tCH tCDH tCCH VIH tCL SCK VIL tDC DIN MSB LSB DOUT HIGH IMPEDANCE Figure 2. SPI Timing Diagram Write Typical Operating Characteristics (VCC = 3.3V and TA = +25°C, unless otherwise noted.) ABSOLUTE TOF ERROR vs. SUPPLY VOLTAGE 32 32 30 30 28 26 24 24 2.2 2.45 2.7 2.95 VCC (V) www.maximintegrated.com 3.2 3.45 3.7 3.
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MAX35101 Time-to-Digital Converter with Analog Front-End Pin Configuration 21 T1 TC 22 T2 GND 23 T4 32KX0 24 T3 32KX1 TOP VIEW 20 19 18 17 GND 25 16 CSW STOP_DN 26 15 WDO STOP_UP 14 RST 27 MAX35101 GND 28 13 DOUT VCC 29 12 DIN GND 30 11 SCK X2 31 10 CE EP 9 1 2 3 4 5 6 7 BYPASS VCC 32KOUT LAUNCH_DN VCC LAUNCH_UP + GND INT 8 CMP_OUT/UP_DN X1 32 TQFP (5mm x 5mm) Pin Description PIN NAME 1, 22, 25, 28, 30 GND 2 BYPASS 3, 6, 29 VCC 4 32KOUT 5
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MAX35101 Time-to-Digital Converter with Analog Front-End Pin Description (continued) PIN NAME 11 SCK CMOS Digital Input. Serial peripheral interface clock input. 12 DIN CMOS Digital Input. Serial peripheral interface data input. 13 DOUT 14 RST Active-Low CMOS Digital Reset Input 15 WDO Active-Low Open-Drain Watchdog Output 16 CSW CMOS Digital Input. Case Switch. Active-high tamper detect input.
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MAX35101 Time-to-Digital Converter with Analog Front-End Block Diagram GND CMP_OUT/UP_DN STOP_UP STOP_DN ANALOG SWITCHING AND BIAS CONTROL TIME-TODIGITAL CONVERTER GND GND GND GND DATA AND STATUS REGISTERS PROGRAMMABLE ALU RST VCC MAX35101 VCC BYPASS INTERNAL LDO STATE MACHINE CONTROLLER DOUT 4-WIRE INTERFACE CONFIGURATION REGISTERS PULSE LAUNCHER HIGH SPEED AND 32 KHZ OSCILLATORS W/REAL TIME CLOCK X1 SCK 8 KBYTES FLASH LAUNCH_UP X2 32KX1 32KX0 32KOUT Detailed Description The
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MAX35101 Time-to-Digital Converter with Analog Front-End TIME OF FLIGHT MEASUREMENTS TOF START T1 T2 HIT1 HIT2 HIT3 HIT4 HIT5 HIT6 TOF MEASUREMENT SEQUENCE Figure 3 AVG = ∑(HIT[1:6]) ÷ 6 LAUNCH PIN COMPARATOR OFFSET STOP PIN WAVE NUMBER COMPARATOR OFFSET RETURN 0 1 2 3 4 5 6 7 8 9 10 11 INT PIN (4) TOF MEASUREMENT DELAY (2) BIAS CHARGE TIME (1) 4 MHZ STARTUP (2) BIAS APPLIED TO STOP PIN TOF COMMAND RECEIVED (3) LAUNCH PULSES STOP HITS SELECTED = 6, STOP POLARITY = POSITIVE EDGE (4) ENABL
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MAX35101 Time-to-Digital Converter with Analog Front-End 7) The t2 wave is detected and the width of the t2 pulse is measured and stored as the t2 time. The wave number for the measurement of the t2 wave width is set by the T2WV[5:0] bits in the TOF2 register. 8) The preferred number of stop hits are then detected. For each hit, the measured TOF is stored in the appropriate HITxUPINT and HITxUPFrac or HITxDNINT and HITxDNFRAC registers.
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MAX35101 Time-to-Digital Converter with Analog Front-End Early Edge Detect The MAX35101 is now ready to measure the successive hits. The next selected wave that is measured is the t2 wave. In the example in Figure 5, this is the 7th wave after the early edge detect wave. The selection of the t2 wave is made with the T2WV[5:0] bits in the TOF2 register. This early edge detect method of measuring the TOF of acoustic waves is used for all of the TOF commands including TOF_UP, TOF_DN, and TOF_DIFF.
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MAX35101 Time-to-Digital Converter with Analog Front-End Temperature Measurement Operations to maximize power efficiency by evaluating the temperature of the RTDs with a coarse measurement prior to a real measurement. The coarse measurement provides an approximation to the TDC converter. During the real measurement, the TDC can then optimize its measurement parameters to use power efficiently.
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MAX35101 Time-to-Digital Converter with Analog Front-End Temperature Error Handling The temperature measurement unit can detect open and/ or short-circuit temperature probes. If the resultant temperature reading in less than 8µs, then the MAX35101 writes a value of 0000h to the corresponding Results registers to indicate a short-circuit temperature probe.
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MAX35101 Time-to-Digital Converter with Analog Front-End Event Timing Mode 2 Event Timing Mode 3 The EVTMG2 command execution causes the TOF_DIFF command to be executed automatically with programmable repetition rates and programmable total counts as shown in Figure 7. The EVTMG3 command execution causes the temperature command to be executed automatically with programmable repetition rates and programmable total counts (Figure 9).
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MAX35101 Figure 7 Time-to-Digital Converter with Analog Front-End Figure 8 EVTMG2 COMMAND TIME OF FLIGHT EVENT HOST MICROCONTROLLER USE OF EVTMG2 TIME OF FLIGHT EVENT START PROGRAM TOF DIFFERENCE MEASUREMENT FREQUENCY (TDF3-TDF0) GET CONFIGURATION REGISTER DATA START TIMER PROGRAMMABLE IN 0.5 SECOND STEPS UP TO 8 SECONDS (EG. EVERY 2 SECONDS) IS TIMER > = NEXT TDF3-TDF0 INCREMENT? PROGRAM NUMBER OF TOF DIFFERENCE MEASUREMENTS (TDM4-TDM0) TO BE TAKEN (EG.
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MAX35101 Figure 9 Time-to-Digital Converter with Analog Front-End Figure 10 EVTMG3 COMMAND TEMPERATURE EVENT HOST MICROCONTROLLER USE OF EVTMG3 TEMPERATURE EVENT START PROGRAM TEMPERATURE DIFFERENCE MEASUREMENT FREQUENCY (TDF5-TDF0) GET CONFIGURATION REGISTER DATA START TIMER TEMPERATURE MEASUREMENT REPETITION RATE PROGRAMMABLE IN 1 SECOND STEPS UP TO 64 SECONDS (EG.
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MAX35101 Time-to-Digital Converter with Analog Front-End Event Timing Mode 1 The EVTMG1 command execution causes the TOF_DIFF command and the temperature command to be executed automatically with programmable repetition rates and programmable total counts. In essence, both the EVTMG2 and EVTMG3 commands are simultaneously executed in a synchronous manner.
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MAX35101 Time-to-Digital Converter with Analog Front-End EVTMG1 TIME OF FLIGHT / TEMPERATURE COMMAND Figure 12 START GET CONFIGURATION REGISTER DATA TOF_DIFF MEASUREMENT REPETITION RATE START TIMER IS TIMER > = NEXT TDF3-TDF0 INCREMENT? YES SET TOF_PENDING NO IS TIMER > = NEXT TDF5-TDF0 INCREMENT? TEMPERATURE MEASUREMENT REPETITION RATE SET TEMPERATURE_ PENDING YES NO NO IS TOF_PENDING SET? NO NO CLEAR TEMPERATURE_ PENDING IS TEMPERATURE_ PENDING SET? PERFORM TOF_DIFF COMMAND YES YES
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MAX35101 Time-to-Digital Converter with Analog Front-End Calibration Operation For more accurate results, calibration of the TDC can be performed. Calibration allows the MAX35101 to perform a calibration measurement that is based upon the 32.768kHz crystal, which is the most accurate clock in the system. This calibration is used when a ceramic oscillator is used in place of an AT-cut crystal for the 4MHz reference. The MAX35101 automatically generates START and STOP signals based upon edges of the 32.
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MAX35101 Time-to-Digital Converter with Analog Front-End For proper alarm function, programming of the ALARM register HOURS bits must match the format (12- or 24-hour modes) used in the Mins_Hrs register. Watchdog Operation The MAX35101 also contains a watchdog alarm. The Watchdog Alarm Counter register is a 16-bit BCD counter that is programmable in 10ms intervals from 0.01s to 99.99s. A seed value may be written to this register representing the start value for the countdown.
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MAX35101 Time-to-Digital Converter with Analog Front-End Opcode Commands Table 2 shows the opcode/commands that are supported by the device. Table 2.
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MAX35101 Time-to-Digital Converter with Analog Front-End TOF_Down Command (01h) The TOF_DOWN command generates a single TOF measurement in the downstream direction. Pulses launch from the LAUNCH_DN pin and are received by the STOP_DN pin. The measured hit results are reported in the HITxDnInt and HITxDnFrac registers, with the calculated average of all the measured hits being reported in the AVGDNInt and AVGDNFrac register. The t1/t2 and t2/ tideal wave ratios are reported in the WVRDN register.
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MAX35101 Time-to-Digital Converter with Analog Front-End EVTMG3 Command (09h) The EVTMG3 command initiates the event timing mode 3 advanced automatic measurement feature. This timing mode performs automatic temperature measurements as described in the Event Timing Operation section. The duration of the automatic measurements depends upon the settings in the Event Timing 1 register, Event timing 2 register, CONT_INT and ET_CONT bits in the Calibration and Control register.
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MAX35101 Time-to-Digital Converter with Analog Front-End Register Opcode Commands of the data register that is addressed in the opcode, and continues with each SCK rising edge until the CE device pin is deasserted as shown in Figure 15. The address counter automatically increments. To manipulate the register memory, there are two commands supported by the device: Read Register and Write register. Each register accessed with these commands is 16 bits in length.
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MAX35101 Time-to-Digital Converter with Analog Front-End Figure 15 CONTINUOUS READ REGISTER COMMAND CE SCK DIN 0 1 2 3 4 5 6 7 8 9 10 19 20 21 22 23 24 25 26 27 39 40 41 42 43 O O MSB LSB 8 BITS DATA 16 BITS OPCODE D HIGH IMPEDANCE DOUT D D D D DATA 16 BITS D D D MSB D D D D D D LSB MSB D D HIGH IMPEDANCE LSB Figure 15.
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MAX35101 Time-to-Digital Converter with Analog Front-End Figure 17 CONTINUOUS WRITE REGISTER COMMAND CE SCK DIN 0 1 2 3 4 O MSB 5 6 7 O 8 BITS OPCODE DOUT 8 D 9 D 10 D 19 D D 20 D 21 D LSB MSB 22 D 24 23 D D 25 D 26 D 27 D LSB MSB DATA 16 BITS 39 D D D LSB DATA 16 BITS HIGH IMPEDANCE Figure 17.
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MAX35101 Time-to-Digital Converter with Analog Front-End RTC and Watchdog Register Descriptions Table 4.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 5. RTC Mins_Hrs Register (continued) BIT NAME 6 12/24 DESCRIPTION 1 = 12-hour mode 0 = 24-hour mode In 12-hour mode 1 = PM 0 = AM In 24-hour mode: 20-hour digit 5 20HR/AM/PM 4 10HR Range 0 to 1 3:0 Hours Range 0 to 9 Table 6.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 7. RTC Month_Year Register WRITE OPCODE 33h READ OPCODE B3h FLASH STORED No Bit 15 14 13 12 Name 0 0 0 10 Month Bit 7 6 5 4 Name DEFAULT VALUE 0000h 11 10 9 8 1 0 Month 3 2 10 Year Year BIT NAME DESCRIPTION 15:13 0 12 10 Month Range 0 to 1 11:8 Month Range 0 to 9 7:4 10 Year Range 0 to 9 3:0 Year Range 0 to 9 These bits always return 0 Table 8.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 9.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 10. TOF1 Register (continued) BIT 15:8 NAME DESCRIPTION PL[7:0] Pulse Launcher Size: This is a hex value that defines the number of pulses that will be launched from the pulse launcher during transmission. The range of this hex value is 00h to FFh. When PL[7:0] is set to 00h, the Pulse Launcher is disabled. Up to 127 pulses can be launched. When PL7 is set, the pulse count is clamped at 127.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 11. TOF2 Register WRITE OPCODE 39h Bit Name Bit Name BIT READ OPCODE B9h FLASH STORED Yes FACTORY-STORED FLASH VALUE 0000h 15 14 13 12 11 10 9 8 STOP2 STOP1 STOP0 T2WV5 T2WV4 T2WV3 T2WV2 T2WV1 7 6 5 4 3 2 1 0 T2WV0 TOF_CYC2 TOF_CYC1 TOF_CYC0 X TIMOUT2 TIMOUT1 TIMOUT0 NAME DESCRIPTION Stop Hits: These bits set the number of stop hits to be expected and measured.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 11. TOF2 Register (continued) TOF Duty Cycle: These bits determine the time delay between successive executions of TOF measurements. It is the start-to-start time of automatic execution of the TOF_UP and the TOF_DN and is applicable only for the TOF_DIFF command. It is based upon the 32.768kHz crystal.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 12.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 13. TOF4 Register WRITE OPCODE 3Bh READ OPCODE BBh FLASH STORED Yes FACTORY-STORED FLASH VALUE 0000h Bit 15 14 13 12 11 10 9 8 Name X X HIT3WV5 HIT3WV4 HIT3WV3 HIT3WV2 HIT3WV1 HIT3WV0 Bit 7 6 5 4 3 2 1 0 Name X X HIT4WV5 HIT4WV4 HIT4WV3 HIT4WV2 HIT4WV1 HIT4WV0 BIT NAME 15:14 X DESCRIPTION Reserved Hit3 Wave Select: These bits select the wave number for which the Hit3 stop time is measured.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 14. TOF5 Register WRITE OPCODE 3Ch READ OPCODE BCh FLASH STORED Yes FACTORY-STORED FLASH VALUE 0000h Bit 15 14 13 12 11 10 9 8 Name X X HIT5WV5 HIT5WV4 HIT5WV3 HIT5WV2 HIT5WV1 HIT5WV0 Bit 7 6 5 4 3 2 1 0 Name X X HIT6WV5 HIT6WV4 HIT6WV3 HIT6WV2 HIT6WV1 HIT6WV0 BIT NAME 15:14 X DESCRIPTION Reserved Hit5 Wave Select: These bits select the wave number for which the Hit5 stop time is measured.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 15.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 15. TOF6 Register (continued) BIT 6:0 NAME DESCRIPTION Comparator Offset Upstream: These bits define an initial selected receive comparator offset voltage for the analog receiver comparator front-end. This comparator offset is used to detect the early edge wave, t1. The actual common-mode voltage is dependent upon and scales with the voltage present at the VCC pins.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 16. TOF7 Register (continued) BIT NAME DESCRIPTION Comparator Return Offset Downstream: When the MAX35101 is measuring the t2 wave, the programmed receive comparator offset is returned to a common-mode voltage automatically after the early edge, t1, is detected. The actual offset return voltage is dependent upon and scales with the voltage present at the VCC pins.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 17.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 18.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 18. Event Timing 2 Register (continued) BIT NAME DESCRIPTION Temperature Port: These bits set the number of temperature ports to stimulate during a temperature measurement sequence and the sequence in which the temperature ports are stimulated.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 19. TOF Measurement Delay Register WRITE OPCODE 41h Bit Name Bit Name BIT 15:0 READ OPCODE C1h FLASH STORED Yes FACTORY-STORED FLASH VALUE 0000h 15 14 13 12 11 10 9 8 DLY15 DLY14 DLY13 DLY12 DLY11 DLY10 DLY9 DLY8 7 6 5 4 3 2 1 0 DLY7 DLY6 DLY5 DLY4 DLY3 DLY2 DLY1 DLY0 NAME DESCRIPTION DLY[15:0] This is hexadecimal value ranging from 0000h to FFFFh (decimal 0 to 65535).
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 20. Calibration and Control Register (continued) BIT NAME DESCRIPTION 10 CMP_SEL Comparator/UP_DN Output Select: This bit selects the output function of the CMP_OUT/UP_DN pin and is only used when CMP_EN = 1. 1 = CMP_EN: The output monitors the receiver front end comparator output. 0 = UP_DN: The output monitors the launch direction of the pulse launcher.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 20. Calibration and Control Register (continued) BIT NAME DESCRIPTION 4MHz Ceramic Oscillator Calibration Period: These bits define the number of 32.768kHz oscillator periods to measure for determination of the 4MHz ceramic oscillator period. 32kHz clock cycles = 1+ CAL_PERIOD[3:0] DESCRIPTION 3:0 CAL_PERIOD[3:0] (decimal) 32kHz CLOCK CYCLES (decimal) 32kHz CLOCK CYCLES (µs) 0 1 30.5 CAL_PERIOD[3:0] 1 2 61 …. …. ….
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 21. Real-Time Clock Register (continued) BIT NAME DESCRIPTION Alarm Control: The MAX35101 contains a time-of-day alarm. The alarm is activated when either the AM1 or AM2 bits are set.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 22. Interrupt Status Register (continued) BIT 12 NAME TOF DESCRIPTION Time of Flight: Set when the TOF_UP, TOF_DN, or TOF_DIFF command has completed. During execution of The EVTMG1 or EVTMG2 command, this bit is set and the INT pin asserts (if enabled) upon completion of each of the cycles of the event defined by the TOF difference measurements setting if the CONT_INT bit in the Calibration and Control register has been set.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 23. Control Register WRITE OPCODE FFh READ OPCODE 7Fh FLASH STORED No DEFAULT VALUE 0000h Bit 15 14 13 12 11 10 9 8 Name X X X X X X AFA CSWA Bit 7 6 5 4 3 2 1 0 Name X X X X X X X X BIT NAME 15:10 X DESCRIPTION Reserved AFA Alarm Flag Arm: This bit is set when the RTC’s hours and/or minutes value matched the alarm settings in the RTC register.
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MAX35101 Time-to-Digital Converter with Analog Front-End Conversion Results Register Descriptions The devices conversion results registers are all read-only volatile SRAM. Values are not stored in the flash memory and the POR value for all registers is 0000h. Table 24. Conversion Results Registers Description READ ONLY ADDRESS NAME DESCRIPTION Bit 15 through Bit 8 holds the 8-bit value of the pulse width ratio (t1 ÷ t2).for the upstream measurement.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 24. Conversion Results Registers Description (continued) READ ONLY ADDRESS NAME CDh Hit5UPInt 15-bit fixed-point integer value of the fifth hit in the upstream direction. This integer portion is a binary representation of the number of t4MHz periods that contribute to the time results. The maximum size of the integer is 7FFFh or (215 - 1) x t4MHz. CEh Hit5UPFrac 16-bit fractional value of the fifth hit in the upstream direction.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 24. Conversion Results Registers Description (continued) READ ONLY ADDRESS NAME DESCRIPTION D7h Hit2DNFrac 16-bit fractional value of the second hit in the downstream direction. This fractional portion is a binary representation of one t4MHz period quantized to a 16-bit resolution. The maximum size of the fraction is FFFFh or (216 - 1)/216 x t4MHz.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 24. Conversion Results Registers Description (continued) READ ONLY ADDRESS NAME E2h TOF_DIFFInt E3h TOF_ DIFFFrac DESCRIPTION 16-bit fixed-point two’s-complement integer portion of the difference of the averages for the hits recorded in both the upstream and downstream directions. It is computed as: AVGUP – AVGDN This integer represents the number of t4MHz periods that contribute to computation.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 24. Conversion Results Registers Description (continued) READ ONLY ADDRESS NAME DESCRIPTION 16-bit fixed-point two’s-complement integer portion of the average of the accumulated TOF_DIFF measurements. It is computed as: TOF_Cycle_Count E5h TOF_DIFF_ AVGInt n=1 TOF_DIFFn TOF_Cycle_Count This integer represents the number of t4MHz periods that contribute to the computation. The maximum size of the integer is 7FFFh or (215 - 1) x t4MHz.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 24. Conversion Results Registers Description (continued) READ ONLY ADDRESS EEh EFh NAME T4Frac Temp_Cycle_ Count DESCRIPTION 16-bit fractional value of the time taken to charge the timing capacitor through the RTD connected to the T4 device pin. This fractional portion is a binary representation of one t4MHz period quantized to a 16-bit resolution. The maximum size of the fraction is FFFFh or (216 1)/216 x t4MHz.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 24. Conversion Results Registers Description (continued) READ ONLY ADDRESS NAME DESCRIPTION F3h T2_AVGFrac 16-bit fractional portion of the average of the T2 port measurements. This fractional portion is a binary representation of one t4MHz period quantized to a 16-bit resolution. The maximum size of the fraction is FFFFh or (216 - 1)/216 x t4MHz. 15-bit fixed-point integer value of the average of the T3 port measurements.
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MAX35101 Time-to-Digital Converter with Analog Front-End Flash Opcode Commands Write Flash Command To access the flash memory, the internal low-dropout voltage regulator that powers the flash circuitry must be enabled. This can be done two ways: sending the LDO_Timed command prior to the desired flash access or sending the LDO_ON command to the MAX35101 prior to desired flash access. See the LDO_Timed and LDO_ON command descriptions for details.
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MAX35101 Time-to-Digital Converter with Analog Front-End Block Erase Flash Command (if enabled) to tell the host microprocessor that the next block erase flash command can be sent. The host microprocessor can read the Interrupt Status register after the INT device pin is asserted instead of waiting for tERASE. A block of 128 words (256 bytes) can be erased in a single operation. For the 8KB array, there are 32 such 128 word (256 Byte) blocks.
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MAX35101 Time-to-Digital Converter with Analog Front-End Table 25. Flash Memory Map FLASH ADDRESS (evens only) BLOCK (decimal) DESCRIPTION 0000h to 00FFh 0 User flash 0100h to 01FFh 1 User flash 0200h to 02FFh 2 User flash …. …. User flash 1D00h to 1DFFh 29 User flash 1E00h to 1EFFh 30 User flash 1F00h to 1FFFh 31 User flash Typical Application Circuit GND GND GND GND GND 3.6V CMP_OUT/UP_DN CSW STOP_UP STOP_DN 3.6V 3.
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MAX35101 Time-to-Digital Converter with Analog Front-End Ordering Information PART Package Information TEMP RANGE PIN-PACKAGE MAX35101EHJ+ -40°C to +85°C 32 TQFP-EP* MAX35101EHJ+T -40°C to +85°C 32 TQFP-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel. *EP = Exposed pad. Chip Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages.
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MAX35101 Time-to-Digital Converter with Analog Front-End Revision History REVISION NUMBER REVISION DATE 0 2/14 DESCRIPTION Initial release PAGES CHANGED — For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied.