AD7150 Analog Devices, AD7150 Datasheet
AD7150
Specifications of AD7150
Available stocks
Related parts for AD7150
AD7150 Summary of contents
Page 1
... The AD7150 operates with a 2 3.6 V power supply specified over the temperature range of −40°C to +85°C. FUNCTIONAL BLOCK DIAGRAM ...
Page 2
... Configuration Register .............................................................. 19 Power-Down Timer Register .................................................... 20 CAPDAC Registers .................................................................... 20 Serial Number Register.............................................................. 20 Chip ID Register......................................................................... 20 Serial Interface ................................................................................ 21 Read Operation........................................................................... 21 Write Operation.......................................................................... 21 AD7150 Reset ............................................................................. 22 General Call ................................................................................ 22 Hardware Design Considerations ................................................ 23 Overview ..................................................................................... 23 Parasitic Capacitance to Ground.............................................. 23 Parasitic Resistance to Ground................................................. 23 Parasitic Parallel Resistance ...................................................... 23 Parasitic Serial Resistance ......................................................... 24 Input Overvoltage Protection ................................................... 24 Input EMC Protection ...
Page 3
... V 0.1 5 μA 2.45 2.65 V Rev Page AD7150 Test Conditions/Comments 4 pF input range 2 pF input range 1 pF input range 0.5 pF input range 4 pF input range 2 pF input range 1 pF input range 0.5 pF input range CIN and EXC pins disconnected CIN and EXC pins disconnected ...
Page 4
... AD7150 Parameter POWER REQUIREMENTS V -to-GND Voltage Current Current Power-Down Mode DD 1 Capacitance units: one picofarad (1 pF × The CAPDAC can be used to shift (offset) the input range. The total capacitance of the sensor can therefore the sum of the CAPDAC value and the conversion input range ...
Page 5
... Exposure to absolute –0 0 maximum rating conditions for extended periods may affect 4 kV device reliability ESD CAUTION –40°C to +85°C –65°C to +150°C 150°C 206°C/W 44°C/W 260(+0/−5)°C 10 sec to 40 sec Rev Page AD7150 ...
Page 6
... Serial Interface Clock Input. Connects to the master clock line. Requires a pull-up resistor if not provided elsewhere in the system. 10 SDA Serial Interface Bidirectional Data. Connects to the master data line. Requires a pull-up resistor if not provided elsewhere in the system. GND SDA 1 10 VDD SCL 2 9 AD7150 CIN2 OUT2 3 8 TOP VIEW (Not to Scale) CIN1 OUT1 4 7 EXC2 EXC1 5 6 Figure 3 ...
Page 7
... CAPACITANCE EXC TO GND (pF 3.3 V, CIN Pin Open Circuit DD 0.10 0. 100 150 200 CAPACITANCE EXC TO GND (pF 3.3 V, CIN to EXC = 0.10 0. 100 150 200 CAPACITANCE EXC TO GND (pF 3.3 V, CIN to EXC = AD7150 250 300 250 300 250 300 ...
Page 8
... AD7150 500 250 0 –250 –500 1 10 RESISTANCE CIN TO GND (MΩ) Figure 10. Capacitance Input Offset Error vs. Resistance CIN to GND 3.3 V, EXC Pin Open Circuit –5 – RESISTANCE CIN TO GND (MΩ) Figure 11. Capacitance Input Gain Error vs. Resistance CIN to GND 3.3 V, CIN to EXC = 2 pF ...
Page 9
... Figure 20. Capacitance Channel Frequency Response 0.50 0.25 0 –0.25 –0.50 75 100 0 Figure 21. CAPDAC Differential Nonlinearity (DNL), Rev Page AD7150 3.0 3.3 V (V) DD Figure 19. EXC Frequency Error vs INPUT SIGNAL FREQUENCY (kHz CAPDAC CODE ...
Page 10
... Figure 22. AD7150 Block Diagram CIN C X 0pF TO 4pF EXC CAPDAC The AD7150 CDC core maximum full-scale input range is 4 pF. However, the part can accept a higher capacitance on the input, and the offset (nonchanging component) capacitance can be balanced by a programmable on-chip CAPDAC The X ...
Page 11
... The AD7150 logic output (active high) indicates either a positive or a negative change in the input capacitance, in both adaptive and fixed threshold modes (see Figure 25 and Figure 26). ...
Page 12
... AD7150 SENSITIVITY In adaptive threshold mode, the output comparator threshold is set as a defined distance (sensitivity) above the data average, below the data average, or both, depending on the selected threshold mode of operation (see Figure 31). The sensitivity value is programmable in the range 0 to 255 LSBs of the 12-bit CDC converter (see the Register Descriptions section) ...
Page 13
... CDC capacitive input range. See the Setup Registers section. POWER-DOWN TIMER In power sensitive applications, the AD7150 can be set to automatically enter power-down mode after a programmed period of time in which the outputs have not been activated. The AD7150 can be then returned to a normal operational mode either via the serial interface or by the power supply off/on sequence ...
Page 14
... AD7150 REGISTER DESCRIPTIONS Table 5. Register Summary Pointer Register (Dec) (Hex) R/W Status 0 0x00 R Ch1 Data High 1 0x01 R Ch1 Data Low 2 0x02 R Ch2 Data High 3 0x03 R Ch2 Data Low 4 0x04 R Ch1 Average High 5 0x05 R Ch1 Average Low 6 0x06 R Ch2 Average High 7 0x07 R Ch2 Average Low ...
Page 15
... RDY1= 0 indicates a finished CDC conversion on Ch1. The bit is reset back to 1 when the Ch1 data register is read via serial interface or after the part reset or power-up. Bit 6 Bit 5 Bit 4 DacStep2 OUT2 DacStep1 Rev Page AD7150 Bit 3 Bit 2 Bit 1 OUT1 C1/C2 RDY2 below the power supply DD ...
Page 16
... BIT 1 BIT 0 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 12-BIT CDC RESULT Figure 36. CDC Data Register The nominal AD7150 CDC transfer function (an ideal transfer function excluding offset and/or gain error) maps the input capacitance between zero scale and full scale to output data codes between 0x3000 and 0xCFF0 only (see Table 8) ...
Page 17
... Figure 39. Threshold Timeout Approaching After a Large Change in CDC Data Toward Threshold DATA AVERAGE + SENSITIVITY DATA AVERAGE THRESHOLD After a Large Change in CDC Data Away from Threshold Rev Page AD7150 LARGE CHANGE IN DATA TOWARDS THRESHOLD TIME TIMEOUT APPROACHING TIMEOUT RECEDING TIME LARGE CHANGE IN DATA AWAY FROM THE THRESHOLD Figure 40 ...
Page 18
... AD7150 SETUP REGISTERS Ch1 Address Pointer 0x0B Ch2 Address Pointer 0x0E 8 Bits, Read/Write, Factory Preset 0x0B Table 10. Setup Registers Bit Map Bit Bit 7 Mnemonic RngH Default 0 Table 11. Setup Registers Bit Descriptions Bit Mnemonic Description 7 RngH Range bits set the CDC input range and determine the step for the AutoDAC function. ...
Page 19
... After finishing the conversion(s), the part goes to the idle mode. 1 Power-Down Powers down the on-chip circuits, except the digital interface. X Reserved Do not use these modes. Rev Page AD7150 Bit 3 Bit 2 Bit 1 EnCh2 MD2 MD1 Output Active When Fixed Threshold Mode Data < ...
Page 20
... AD7150 POWER-DOWN TIMER REGISTER Address Pointer 0x10 8 Bits, Read/Write, Factory Preset 0x00 Table 14. Power-Down Timer Register Bit Map Bit Bit 7 Mnemonic – Default 0 Table 15.Power-Down Timer Register Bit Descriptions Bit Mnemonic Description [7:6] – These bits must be 0 for proper operation. [5:0] Power-Down Defines period duration of the power-down timeout ...
Page 21
... In this case, the AD7150 becomes a slave transmitter. In all instances, the AD7150 acts as a standard slave device on the serial bus. The start byte address for the AD7150 is 0x90 for a write and 0x91 for a read. READ OPERATION When a read is selected in the start byte, the register that is currently addressed by the address pointer is transmitted to the SDA line by the AD7150 ...
Page 22
... The general call address is for addressing every device connected to the serial bus. The AD7150 acknowledges this address and reads in the following data byte. If the second byte is 0x06, the AD7150 is reset, completely uploading all default values. The AD7150 does not respond to the serial bus commands (do not acknowledge) during the default values upload for approximately 2 ms ...
Page 23
... GND for CIN and information about excitation). See Figure 4 to Figure 9. PARASITIC RESISTANCE TO GROUND R GND1 R The AD7150 CDC result is affected by a leakage current from C to ground; therefore The equivalent resistance between C maximized (see Figure 45). See Figure 10 to Figure 13. ...
Page 24
... PARASITIC SERIAL RESISTANCE R S1 CIN EXC Figure 47. Parasitic Serial Resistance The AD7150 CDC result is affected by a resistance in series with the measured capacitance. The total serial resistance ( Figure 47) should be on the order of hundreds of Ω. S2 See Figure 14. INPUT OVERVOLTAGE PROTECTION R S1 CIN ...
Page 25
... Figure 52. AD7150 Interfaced to a Host Microcontroller 1kΩ 0.1µF 10µF VDD CIN1 1kΩ 1kΩ AD7150 SDA EXC1 SCL OUT1 CIN2 OUT2 EXC2 GND Figure 53. AD7150 Standalone Operation with EMC Protection Rev Page 1kΩ 3V BATTERY 1kΩ LED2 3.3V 1kΩ HOST MICROCONTROLLER SDA SCL IRQ1 IRQ2 V 3.3V SUPPLY ADP1720-3 ...
Page 26
... AD7150 OUTLINE DIMENSIONS ORDERING GUIDE Model Temperature Range 1 AD7150BRMZ −40°C to +85°C 1 AD7150BRMZ-REEL −40°C to +85° RoHS Compliant Part. 3.10 3.00 2. 5.15 3.10 4.90 3.00 4.65 2. PIN 1 0.50 BSC 0.95 0.85 1.10 MAX 0.75 0.15 0.33 SEATING 0.23 0.05 PLANE 0.17 0.08 COPLANARITY 0.10 COMPLIANT TO JEDEC STANDARDS MO-187-BA Figure 54. 10-Lead Mini Small Outline Package [MSOP] ...
Page 27
... NOTES Rev Page AD7150 ...
Page 28
... AD7150 NOTES Purchase of licensed components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I 2 Rights to use these components system, provided that the system conforms to the I ©2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners ...