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PNI ASIC

3-Axis Magneto-Inductive Sensor Driver and Controller

with SPI Serial Interface

General Description

The PNI (11096) ASIC is a low cost magnetic

Measurement Application Specific Integrated Circuit

designed for use with PNI Corporation’s magneto-

inductive sensors. The PNI ASIC can control and

measure three independent magneto-inductive

sensors. Each sensor is individually selectable for

measurement, and can also be individually

configured for measurement resolution. The PNI

ASIC has diagnostic modes and outputs to test the

oscillator and counter circuits.

The PNI ASIC contains the entire measurement

circuit, both analog and digital sections. Each sensor

changes its inductance with an applied change in

magnetic field parallel to the sensor. In order to make

a measurement, the sensor is switched into an L/R

oscillator circuit. The bipolar differential

measurement scheme used by the PNI ASIC makes

the magnetic measurement inherently temperature

independent. It also has the benefit of transforming

the measurement range into a zero centered, positive/

negative value.

Features

 Low supply current:

<500 µA at 3 VDC

<1 µA, idle mode

 Complete 3-axis magnetic sensor driver

 Ultra-low magnetic signature in Die form

 Flexible supply voltage: 2.2 to 5.0 V

 Fast sample rate: up to 2000 samples/second

 Wide dynamic range: 96 dB (16 bits) in

hardware with 18 dB (3 bits) additional gain

scaling available

 Fully digital interface: SPI protocol

Applications

 Compassing

 Magnetometer instruments

 Magnetic object sensing

 Magnetic ink sensing

Ordering Information

Name Part # MOQ Pkg.

RoHS

Compliant

26 pad Die 10174 1,000 tray Yes

28 pin MLF 12576 5000 reel Yes

28 pin MLF 12576P 1

cut-

tape

Yes

Table 1

PNICorporation133AviationBlvd.,Suite101,SantaRosa,CA95403‐1084USAUpdated27‐April‐09

Phone:(707)566‐2260,Fax:(707)566‐2261,Web:www.pnicorp.com

Summary of content (19 pages)

PAGE 1
PNI ASIC 3-Axis Magneto-Inductive Sensor Driver and Controller with SPI Serial Interface General Description Features The PNI (11096) ASIC is a low cost magnetic Measurement Application Specific Integrated Circuit designed for use with PNI Corporation’s magnetoinductive sensors. The PNI ASIC can control and measure three independent magneto-inductive sensors. Each sensor is individually selectable for measurement, and can also be individually configured for measurement resolution.
PAGE 2
PNI ASIC Specifications SPECIFICATIONS CAUTION: Stresses beyond those listed under Table 2 may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied.
PAGE 3
PNI ASIC Specifications Electrical Specifications Parameter voltage and current levels Testing for the currents listed in Table 4 assume a static test setup with measurements performed while static data is applied to the device. Test type parameters apply as listed in the Table 8: Pin Definitions Table 4: Inputs Vila Test Type Viha Iilb Iihb AIB (analog input) 0.2 Vdd 2.0 Vdd 0.0 to -1.0 µA 0.0 to 1.0 µA IBA (CMOS) 0.25 Vdd 0.8 Vdd 0.0 to -1.0 µA 0.0 to 1.0 µA IBT (CMOS, SC Hsy = 1.0)c 0.
PAGE 4
PNI ASIC Theory of Operation Theory of Operation The PNI ASIC contains the entire measurement circuitry necessary to use PNI Corporation’s magnetoinductive sensors as well as bus interface circuitry. Communication between the PNI ASIC and the host microprocessor is over SPI bus interface. After being reset a single 8 bit command from the host system configures and initiates an axis sample from the ASIC.
PAGE 5
PNI ASIC Theory of Operation Figure 2: Forward Bias versus Reverse Bias illustrates the change between these two measurements. The actual magnetic measurement is the difference between these two measurements. This measurement scheme is used to make the magnetic measurement temperature independent. It also has the benefit of transforming the measurement range into a zero centered, positive/negative value. The PNI ASIC returns the data to the host microprocessor over the SPI interface.
PAGE 6
PNI ASIC Theory of Operation CONNECTIONS A typical connection configuration is shown in Figure 4 with the analog and digital sections of the PNI ASIC tied together. This configuration is adequate for compassing applications. For higher performance applications where less noise is desirable, separating the sections is recommended. The PNI ASIC can control up to three sensors; if less are needed, the unneeded pins should be left to float.
PAGE 7
PNI ASIC Host Processor Interface Host Processor Interface All accesses to and from the PNI ASIC are through a hardware handshaking, synchronous serial interface that adheres to the Motorola SPI protocol. The interface consists of six signals; SCLK, MOSI, MISO, SSNOT, RESET and DRDY. Table 8: Pin Definitions 26 DIE (pin #) 28 MLF (pin #) Pin Name I/O Typea Test Type Parameters Description 1 26 VSTBY DP VDD Input protection clamp diode.
PAGE 8
PNI ASIC Host Processor Interface SPI Port Line Descriptions MOSI – Master Out Slave In The data sent from the master to the PNI ASIC. Data is transferred most significant bit first. The MOSI line will accept data once the SPI is enabled by taking SSNOT low. Valid data must be presented at least 100 nS before the rising edge of the clock, and remain valid for 100 nS after the edge.
PAGE 9
PNI ASIC Host Processor Interface Hardware Handshaking Line Descriptions RESET RESET is usually low. RESET must be toggled from low-high-low. DRDY – Data Ready DRDY is low after a RESET; after a command has been received and the data is ready, DRDY will be high. It is recommended that the DRDY line always be used to ensure that the data is clocked out of the PNI ASIC only when it is available.
PAGE 10
PNI ASIC Host Processor Interface Figure 5: SPI Port Full Timing Sequence (cpol = 0 ) Figure 6: SPI Port Timing Parameters (cpol = 0) SPI Port Usage Tips A SPI port can be implemented using different clock polarity options. The clock polarity used with the PNI ASIC must be normally low, (cpol = 0). Figure 6 graphically shows the timing sequence (cpol = 0). Data is always considered valid while the SCLK is high (tDASH = Time, Data After SCLK High).
PAGE 11
PNI ASIC Host Processor Interface Idle Mode The PNI ASIC does not initialize in the idle mode at power-up. The PNI ASIC must be in a data-ready state for the idle mode to occur. After power-up the PNI ASIC can be brought to the data-ready state by following these steps for sending a read command to the PNI ASIC. 1. Set SSNOT low. 2. Pulse the RESET line. 3. Send a command to the PNI ASIC to measure one of the sensors. 4.
PAGE 12
PNI ASIC Host Processor Interface PS0, PS1, and PS2 – Period Select Selects the division ratio applied to the L/R oscillator output to set the period being measured. Table 11: Period Select PS2 PS1 PS0 Ratio 0 0 0 /32 0 0 1 /64 0 1 0 /128 0 1 1 /256 1 0 0 /512 1 0 1 /1024 1 1 0 /2048 1 1 1 /4096 ODIR – Oscillator Direction Determines the magnetic oscillator direction if MOT is set to 1. It has no effect on direction when the MOT bit is set to zero.
PAGE 13
PNI ASIC Host Processor Interface Response Word PNI ASIC will return the result of a complete forward and reverse bias measurement of the sensor in a 16-bit 2’s compliment format. The range is – 32768 to 32767. PNI Corporation 133 Aviation Blvd., Suite 101, Santa Rosa, CA 95403‐1084 USA;, Fax: (707) 566‐2261 For the most current specifications, please visit our website at: www.pnicorp.
PAGE 14
PNI ASIC Package Information Package Information Pin Configuration Figure 7: Pin Configuration PNI Corporation 133 Aviation Blvd., Suite 101, Santa Rosa, CA 95403‐1084 USA;, Fax: (707) 566‐2261 For the most current specifications, please visit our website at: www.pnicorp.
PAGE 15
PNI ASIC Package Information 28 Lead MLF (5 x 5 mm) Outline Dimensions Figure 8: 28 Lead MLF (5 x 5 mm) Outline Dimensions PNI Corporation 133 Aviation Blvd., Suite 101, Santa Rosa, CA 95403‐1084 USA;, Fax: (707) 566‐2261 For the most current specifications, please visit our website at: www.pnicorp.
PAGE 16
PNI ASIC Package Information 28 Lead MLF (5 x 5 mm) Tape & Reel Dimensions Figure 9: 28 Lead MLF (5 x 5 mm) Tape & Reel Dimensions PNI Corporation 133 Aviation Blvd., Suite 101, Santa Rosa, CA 95403‐1084 USA;, Fax: (707) 566‐2261 For the most current specifications, please visit our website at: www.pnicorp.
PAGE 17
PNI ASIC Package Information Die Package Mechanical Specifications Die size is 2580 µm x 2360 µm (with scribe line). All X and Y coordinates refer to the center of the die. Figure 10: Mechanical Specifications PNI Corporation 133 Aviation Blvd., Suite 101, Santa Rosa, CA 95403‐1084 USA;, Fax: (707) 566‐2261 For the most current specifications, please visit our website at: www.pnicorp.
PAGE 18
PNI ASIC Package Information Die Package Mechanical Specifications Table 13: Die Pad Descriptions Pad Function X (mm) Y (mm) 1 VSTBY –655 968 2 SCLK –755 968 3 MISO –893 968 4 MOSI –1012 968 5 SSNOT –1128 968 6 AVDD –1125 226 7 AVSS –1125 62 8 APZDRV –1125 –81 9 APZIN –1134 –966 10 ANZIN –1012 –966 11 ANZDRV –893 –966 12 APYDRV –448 –966 13 APYIN –3 –966 14 DVDD 115 –966 15 ANYIN 237 –966 16 ANYDRV 357 –966 17 APXDRV 802 –966 18 APXIN
PAGE 19
Recommended Processing Parameters Figure 11: Lead Free Reflow Profile Table 14 Recommended Processing Parametersa Reflow Parameter Temperature (°C) Time (sec) Preheat Temperature (TSmin to TSmax) 150°C – 200°C 60-180 Temperature TL (typical solder melting point) >218°C TSmax to TL Ramp-up Rate 3°C/second max Peak Temperature TP 260°C Time 25°C to Peak TP 6 minute max Time Maintained Above Temperature TL (tL) 218°C Soak (time within 5° of actual Peak TP) Ramp-down Rate 60-120 10-20 4°C/sec