133 Aviation Blvd., Suite 101 Santa Rosa, CA 95403-1084 USA 707-566-2260 main 707-566-2261 fax www.pnicorp.com Transitioning from A-Series To F-Series Sensors PNI’s new Sen-XY-f and Sen-Z-f geomagnetic sensors (F-series sensors) represent a significant improvement in magnetic sensing performance when compared with alternative magnetic sensors, including PNI’s legacy Sen-XY and Sen-Z sensors (A-series sensors). The new F-series sensors provide lower noise, lower power consumption, improved gain and resolution, and reduced unit-to-unit variability. This document reviews the differences between the sensors, and how to implement F-series sensors into an existing system that currently uses A-series sensors. Specification Differences The table below consolidates performance specifications for both sensors. Specifications assume the sensor is mated to PNI’s 3D MagIC ASIC. Table 1: Specification Differences Parameter Units A-Series F-Series H 400-600 typ. 500-600 typ. 30 same %/C 0.4 typ. same Operating Voltage Range V 1.6 to 3.3 same Field Measurement Range* T -1100 to +1100 -800 to +800 Gain @ 200 cycle counts (Resolution = 1/Gain) counts/ T 45 @ 3.3V 45 @ 3.3V (same) 55 @ 2.8V Noise @ 200 cycle counts nT 35 30 % of 200 T 0.6 typ., 1.0 max same mA 0.3 @ 3.3V 0.20 @ 2.8V 0.25 @ 3.3V Linear Regime 33 + (V-1.6)*35 [1.6V to 2.6V] 60 + (V-1.6)*67 [1.6 V to 2.2V] Fixed Regime 68 [2.6V to 3.3V] 100 [2.2V to 3.3V] 33 same kHz 185 195 C -40 to +85 same Inductance DC Resistance @ 25C 15C Resistance vs. Temperature Linearity - best fit over 200 T Average Current per Axis 35 Hz & 200 Cycle Counts Recommended Bias Resistance External Timing Resistor (REXT) Circuit Oscillation Frequency Operating Temperature *The F-Series field measurement range can be extended if necessary, but involves trade-offs. Contact PNI if you require >±800 T range. PNI Sensor Corp. Page 1 of 2 August 21, 2010 133 Aviation Blvd., Suite 101 Santa Rosa, CA 95403-1084 USA 707-566-2260 main 707-566-2261 fax www.pnicorp.com Mechanical Differences The legacy Sen-XY and new Sen-XY-f have the same footprint and overall mechanical dimensions. And the new Sen-XY-f can be accommodated by the Sen-XY’s pad layout. Note that the RM-3000-f & RM2000-f User Manual recommends a different pad layout than the RM-3000 & RM2000 User Manual. The reason for the change is PNI has found the new layout makes rework easier. This is true for either version of the sensor. The legacy layout recommendation, however, is still acceptable and allows for the smallest footprint. The new Sen-Z-f is available in two versions, a backward-compatible version, pn 13070, and a physically more robust version, pn 13101. The 13070 has the same footprint ,dimensions, and recommend pad layout as the legacy Sen-Z, pn 12779. The 13101 is taller and has a larger solder pad area, which results in a much more robust sensor-to-PCB solder joint and eliminates any need for the Sen-Z shield. Indeed, the Sen-Z shield is uncompatible with the 13101 sensor. Dimensions for the 12779, 13070, 13101, and Sen-Z shield are given below. For additional information and drawings, see the appropriate user manual. Table 2: Sen-Z and Sen-Z-f Dimensions Units PN 12779 & 13070 PN 13101 Sen-Z Shield Height mm 5.75 max 6.35 max 6.10 typ. Footprint mm 3x3 3.9 x 3 5.7 x 4.1 Recommended Solder Pad (allowing for rework) mm 4.0 x 2.4 5.2 x 1.95 6.5 x 4.0 Parameter Implementation of F-Series Sensors If the user wants to implement the new F-Series sensors with minimal effort, then the only required change is to switch the bias resistors. For most users this means changing the bias resistor on all their sensors from 68 to 100 , although if the system is operating at <2.6 V then Table 1 should be consulted. Changing the bias resistors is the one change that absolutely should be made. If operating at <3 V, then changing to F-series sensors will somewhat increase the gain of the system. In this case it may be desirable to reduce the number of cycle counts in software in order to further decrease power consumption while retaining gain and resolution. Alternatively, if nothing is changed in software, then the gain and resolution of the system will improve. For the Sen-Z-f, the user may decide to use the more robust 13101, rather than the backwardcompatible 13070. In this case, the pad layout should change per the RM-3000-f & RM2000-f User Manual. PNI Sensor Corp. Page 2 of 2 August 21, 2010