MagTek TRIPLE TRACK Delta ASIC - Manual (Page 21)

Triple Track ASIC
17
PRINTED CIRCUIT BOARD LAYOUT RECOMMENDATIONS AND SCHEMATICS
General Guidelines
As with any analog or mixed-signal circuit, PCB layout must be approached with care to achieve optimal
results with the Triple Track ASIC.
• The low-level analog head signals must be routed clear of any noise sources or digital signals.
Use a quiet ground or other low impedance DC source to shield if necessary.
• The loop formed by each head signal conductor and its return path must be minimized to reduce
noise pickup. Each track’s pair of conductors must be routed with minimal clearance between
them.
• The chip should be decoupled with a 0.1µF ceramic capacitor placed as close as possible to the
DVDD and DVSS pins with minimal inductance between the capacitor and the chip.
• DO NOT add additional head loading (resistance or capacitance) to the circuit. Head loading for
this chip is dynamic and built into the chip. Additional head loading may degrade performance.
• Unused HEAD_A/B/C pins must not be connected to any potential.
IntelliHead
The Triple Track ASIC is also available integrated into a magnetic head. As an alternative to a separate
ASIC and magnetic head, the Shift-Out IntelliHead product can be easily accommodated on the PCB with
very little if any additional board area. Shown in each of the recommended PCB layouts for the Triple
Track ASIC is a “hook” for the Shift-Out IntelliHead in the form of a 5-pin connector. If using the Shift-
Out IntelliHead, the only component that need be installed on the board is this 5 pin connector. If not
using the Shift-Out IntelliHead, the 7-pin connector
2
along with all the other components is installed
instead of the 5 pin connector. The 7 pin and 5 pin connectors are mutually exclusive in terms of
installation. MagTek recommends that this “hook” be included in all Triple Track ASIC PCB layouts so
that the customer may have the option of using the Shift-Out IntelliHead with its performance benefits
and possible future cost reduction benefits.
A note concerning Shift-Out IntelliHead compatibility: The on-chip memory tracks of the Shift-Out
IntelliHead are permanently assigned to particular tracks of the magnetic head via internal wires
connecting the head coil wires to particular inputs of the built-in ASIC. Typically the dual-track Shift-
Out IntelliHead serves as a track 1&2 reader. As such, tracks ‘A’ and ‘B’ of the ASIC correspond to
tracks ‘1’ and ‘2’ of the reader respectively when the Shift-Out IntelliHead on a spring is mounted as
designed, with the centerline of the spring mounting holes running through the center of track 2. For the
less common track 2&3 reader, this Shift-Out IntelliHead/spring assembly may be used in an inverted
configuration on the same chassis used by a track 1&2 reader. In this case, on-chip memory track ‘A’
corresponds to physical magnetic stripe track 3, and on-chip memory track ‘B’ corresponds to physical
magnetic stripe track 2. This is important since it affects the arrangement of the data upon extraction
from the chip. For the triple-track Shift-Out IntelliHead, tracks ‘A’, ‘B’, and ‘C’ of the ASIC are assigned
to tracks ‘1’, ‘2’, and ‘3’ respectively of the reader. MagTek recommends that these track assignments be
2 Some MagTek head assemblies use different connectors and pin assignments. Be sure to check your particular head
assembly.