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 benefts early edge detect ultrasonic time-of-flight ? time-to-digital accuracy down to 20ps ? measuremen t range up to 8ms ? multihit capa bility ? early edge detect to provide advanced accuracy ? programmab le tof hit accumulator ? t wo channels: single-stop channel ? stop-enable windowing with edge trigger select ? built-in pulse launcher with programmable frequency ? autozero receiver comparator ? programmab le acoustic recovery sensitivity ? automatic two-pulse algorithm for differential tof measurement temperature measurement ? up to four (4) 2-wire sensors ? pt1000 and pt500 r td 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 oscilla tor can be a ceramic device to lower system cost ? small, 5mm x 5mm, 32-pin tqfp package ? 4-wire spi interface ? -40c to +85c operation ordering information appears at end of data sheet. for related parts and recommended products to use with this part, refer to www.maximintegrated.com/MAX35101.related . 19-6830; rev 0; 2/14 evaluation kit available MAX35101 time-to-digital converter with analog front-end abridged data sheet
(voltages relative to ground.) voltage range on v cc pins ................................. -0.5v to +4.0v voltage range on all other pins (not to exceed 4.0v) ............................. -0.5v to (v cc + 0.5v) continuous power dissipation (t a = +70c) tqfp (derate 27.80mw/oc above +70c) ........... 2222.20mw operating temperature range ........................... -40c to +85c junction temperature ...................................................... +150c storage temperature range ............................ -55c to +125c lead temperature (soldering, 10s) ................................. +300c soldering temperature (reflow) ....................................... +260c esd protection (all pins, human body model) .................. 2kv tqfp junction-to-ambient thermal resistance ( ja ) .......... 36c/w junction-to-case thermal resistance ( jc ) ..................... 4c/w (note 1) (v cc = 2.3v to 3.6v, t a = -40 c to +85 c, unless otherwise noted. typical values are at v cc = 3.0v and t a = +25c.) (notes 2, 3) (t a = -40 c to +85c, unless otherwise noted.) (notes 2, 3) parameter symbol conditions min typ max units supply voltage v cc 2.3 3.0 3.6 v input logic 1 (rst , csw, sck, din, ce) v ih v cc x 0.7 v cc + 0.3 v input logic 0 (rst , csw, sck, din, ce) v il -0.3 v cc x 0.3 v input logic 1 (32kx1) v ih32kx1 v cc x 0.85 v cc + 0.3 v input logic 0 (32kx1) v il32kx1 -0.3 v cc x 0.15 v parameter symbol conditions min typ max units input leakage (csw, rst, sck, din, ce) i l -0.1 +0.1 a output leakage (int, wdo, t1,t2,t3,t4) -0.1 +0.1 a output voltage low (32kout) v ol32k 2ma 0.2 x v cc v output voltage high (32kout) v oh32k -1ma 0.8 x v cc v output voltage high (dout, cmp_out/up_dn) v oh -4ma 0.8 x v cc v output voltage high (tc) v ohtc v cc = 3.3v, i out = -4ma 2.9 3.1 v maxim integrated 2 note 1: package thermal resistances were obtained using the method described in jedec specification jesd51-7, using a four-layer board. for detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial . absolute maximum ratings 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 in the operational sections of the specifications is not implied. exposure to ab solute maximum rating conditions for extended periods may affect device reliability. package thermal characteristics electrical characteristics recommended operating conditions MAX35101 time-to-digital converter with analog front-end www.maximintegrated.com abridged data sheet
(v cc = 2.3v to 3.6v, t a = -40 c to +85 c, unless otherwise noted. typical values are at v cc = 3.0v and t a = +25c.) (notes 2, 3) parameter symbol conditions min typ max units output voltage high (launch_up, launch_dn) v ohlauch v cc = 3.3v, i out = -50ma 2.8 3.0 v output voltage low ( wdo, int, dout, cmp_out/up_dn) v ol 4ma 0.2 x v cc v pulldown resistance (tc) r tc 650 1000 1500 ? input voltage low (tc) v iltc 0.36 x v cc v output voltage low (launch_up, launch_dn) v ollauch v cc = 3.3v, i out = 50ma 0.2 0.4 v resistance (t1, t2, t3, t4) r on 1 ? input capacitance (ce, sck, din, rst, csw) c in not tested 7 pf rst low time t rst 100 ns current standby current i ddq no oscillators running, t a = +25c 0.1 1 a 32khz osc current i 32khz 32khz oscillator only (note 4) 0.5 0.9 a 4mhz osc current i 4mhz 4mhz oscillator only (note 4) 40 85 a ldo bias current i ccldo i cccpu = 0 (note 4) 15 35 a time measurement unit current i cctmu (note 4) 4.5 8 ma calculator current i cccpu 2.5 5 ma device current drain i cc3 tof_diff = 2 per second (3 hits), temperature = 1 per 30s 10 a i cc6 tof_diff = 2 per second (6 hits), temperature = 1 per 30s 13 flash erase current i flash 0.5 1 ma analog receiver analog input voltage (stop_up, stop_dn) v ana 10 700 2 x v cc x (3/8) mv p-p input offset step size v step 1 mv stop_up/stop_dn bias voltage v bias v cc x (3/8) v receiver sensitivity v ana stop hit detect level (note 5) 10 mv p-p time measurement unit measurement range t meas time of fight 8 8000 s time measurement accuracy t acc differential time measurement 20 ps time measurement resolution t res 3.8 ps maxim integrated 3 electrical characteristics (continued) MAX35101 time-to-digital converter with analog front-end www.maximintegrated.com abridged data sheet
pin name function 1, 22, 25, 28, 30 gnd device ground 2 bypass connect this pin to ground with a capacitor (100nf) to provide stability for the on-board low- dropout regulator that is used to supply the fash circuitry. the effective series resistance of this capacitor needs to be in the 1? to 2? range. 3, 6, 29 v cc main supply. typically sourced from a single lithium cell. 4 32kout cmos output. repeats the 32khz crystal oscillator frequency. 5 launch_dn cmos pulse output transmission in downstream direction of water flow 7 launch _up cmos pulse output transmission in upstream direction of water flow 8 cmp_out/up_dn cmos output. indicates the direction (upstream or downstream) of which the pulse launcher is currently launching pulses or the comparator output. 9 int active-low open-drain interrupt output. the pin is driven low when the device requires service from the host microprocessor. 10 ce active-low cmos digital input. serial peripheral interface chip enable input. tqfp (5mm x 5mm) top view 29 30 28 27 12 11 13 bypass 32kout launch_dn v cc launch_up 14 gnd 32kx0 tc t4 32kx1 t3 t2 1 + 2 gnd 4 5 6 7 2324 22 20 19 18 v cc gnd rst dout din sck v cc gnd 3 21 31 10 x2 ce ep 32 9 x1 int stop_up 26 15 wdo stop_dn 25 16 csw cmp_out/up_dn t1 8 17 gnd MAX35101 maxim integrated 7 pin description pin confguration MAX35101 time-to-digital converter with analog front-end www.maximintegrated.com abridged data sheet
pin name function 11 sck cmos digital input. serial peripheral interface clock input. 12 din cmos digital input. serial peripheral interface data input. 13 dout cmos output. serial peripheral interface data output. 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. 17 t1 open-drain probe 1 temperature measurement 18 t2 open-drain probe 2 temperature measurement 19 t3 open-drain probe 3 temperature measurement 20 t4 open-drain probe 4 temperature measurement 21 tc input/output temperature measurement capacitor connection 23 32kx0 connections for 32.768khz quartz crystal. an external cmos 32.768khz oscillator can also drive the MAX35101. in this confguration, the 32kx1 pin is connected to the external oscillator signal and the 32kx0 pin is left unconnected. 24 32kx1 26 stop_dn downstream stop analog input. used for the signal that is received from the downstream transmission of a time-of-fight measurement. 27 stop_up upstream stop analog input. used for the signal that is received from the upstream transmission of a time-of-fight measurement. 31 x2 connections for 4mhz quartz crystal. a ceramic resonator can also be used. 32 x1 ep exposed pad. connect to gnd. maxim integrated 8 pin description (continued) MAX35101 time-to-digital converter with analog front-end www.maximintegrated.com abridged data sheet
time-to- digital converter programmable alu data and status registers state machine controller pulse launcher stop_up temperature measurement high speed and 32 khz oscillators w/real time clock x1 4-wire interface cmp_out/up_dn analog switching and bias control internal ldo MAX35101 stop_dn v cc v cc v cc bypass launch_up launch_dn gnd gnd gnd gnd gnd configuration registers 8 kbytes flash wdo csw int rst sck dout din ce x2 32kx1 32kout 32kx0 t1 t2 t3 t4 tc maxim integrated 9 block diagram MAX35101 time-to-digital converter with analog front-end www.maximintegrated.com abridged data sheet
4-wire interface analog switching and bias control time-to-digital converter programmable alu data and status registers 8kb flash state machine controller configuration registers internal ldo pulse launcher x1 12pf x2 32.768khz 32kx1 12pf 32kx0 12pf 4mhz 12pf 32kout microcontroller t1 t2 t3 t4 tc pt 1000 1k (50ppm) metal film 100 nf cog (np0) (30ppm/c) din ce dout sck rst int wdo csw stop_up launch_up launch_dn stop_dn v cc bypass 100nf low esr piezoelectric transducers cmp_out/up_dn v cc v cc 3.6v high-speed and 32khz oscillators with real-time clock temperature measurement MAX35101 3.6v gndgndgndgndgnd pt 1000 3.6v 3.6v maxim integrated 64 typical application circuit MAX35101 time-to-digital converter with analog front-end www.maximintegrated.com abridged data sheet
+deno tes a lead(pb)-free/rohs-compliant package. t = tape and reel. * ep = e xposed pad. part temp range pin-package MAX35101ehj+ -40c to +85c 32 tqfp-ep* MAX35101ehj+t -40c to +85c 32 tqfp-ep* package type package code outline no. land pattern no. 32 tqfp-ep h32e+6 21-0079 90-0326 maxim integrated 65 package information for the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages . note that a +, #, or - in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. chip information process: cmos ordering information MAX35101 time-to-digital converter with analog front-end www.maximintegrated.com abridged data sheet
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