EVALUATION KIT AVAILABLE
MAX35102
Time-to-Digital Converter
Without RTC
General Description
Features and Benefits
● High-Accuracy Flow Measurement for Billing and
The MAX35102 is a time-to-digital converter with built-in
amplifier and comparator targeted as a low-cost, analog
front-end solution for the ultrasonic heat meter and flow
meter markets. It is similar to the MAX35101, but with a
reduced feature set and without a real-time clock (RTC).
The package size has been reduced to 4mm x 4mm x
0.75mm with 0.4mm pin pitch.
Leak Detection
• Time-to-Digital Accuracy Down to 20ps
• Measurement Range Up to 8ms
• 2 Channels—Single-Stop Channel
● High-Accuracy Temperature Measurement for
Precise Heat and Flow Calculations
• Up to Four 2-Wire Sensors
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.
• PT1000 and PT500 RTD Support
• 40mK Accuracy
● Maximizes Battery Life with Low Device and Overall
System Power
Power consumption is the lowest available with ultra-low
5.5μA ToF measurement and < 125nA duty-cycled tem-
perature measurement.
• Ultra-Low 5.5μA ToF measurement and < 125nA
Duty-Cycled Temperature Measurement
• 2.3V to 3.6V Single-Supply Operation
Applications
● Ultrasonic Heat Meters
● Ultrasonic Water Meters
● Ultrasonic Gas Meters
● High-Integration Solution Minimizes Parts Count and
Reduces BOM Cost
• Small, 4mm x 4mm, 32-Pin TQFN Package
• -40°C to +85°C Operation
Ordering Information appears at end of data sheet.
System Block Diagram
CMP_OUT/UP_DN
GND
STP_UP
DATA AND
INTX
ANALOG SWITCHING
AND BIAS CONTROL
TIME-TO-DIGITAL
CONVERTER
PROGRAMMABLE ALU
STATUS
REGISTERS
STP_DN
RSTX
3.6 V
VCC
SCK
INTERNAL
LDO
MICROCONTROLLER
BYPASS
DOUT
STATE MACHINE
CONTROLLER
100 NF LOW ESR
4-WIRE
INTERFACE
LAUNCH_UP
LAUNCH_DN
DIN
CONFIGURATION
REGISTERS
PULSE
LAUNCHER
CEX
PIEZOELECTRIC
TRANSDUCERS
HIGH SPEED AND 32 KHZ OSCILLATORS
TEMPERATURE MEASUREMENT
T1
T2
T3
T4
TC
32KOUT
X1
X2
32KX1
32KXO
1K (50 PPM)
METAL FILM
32.768 KHZ
12 PF
4 MHZ
12 PF
12 PF
100 NF COG (NP0) (30
PPM/C)
12 PF
19-7442; Rev 0; 11/14