MC68HC05V12 Datasheet, PDF (202/246 Pages) Freescale Semiconductor, Inc – HCMOS Microcontreller Unit

Gauge Drivers
Freescale Semiconductor, Inc.
NOTE:
The V_GSUP pin requires a 100 µF low ESR capacitor for regulator
stability. In addition, the V_DD and V_CCA pins should have the usual 0.1
µF bypass capacitors to V_SS and V_SSA, respectively.
To provide effective decoupling and to reduce radiated RF emissions,
the small decoupling capacitors must be located as close to the supply
pins as possible. The self-inductance of these capacitors and the
parasitic inductance and capacitance of the interconnecting traces
determine the self-resonant frequency of the decoupling network. Too
low a frequency will reduce decoupling effectiveness and could increase
radiated RF emissions from the system. A low-value capacitor (470 pF
to 0.01 µF) placed in parallel with the other capacitors will improve the
bandwidth and effectiveness of the network.
15.10 Gauge Regulator Accuracy
The on-chip portion of the regulator will contribute no more than E_GS
percent to the variation in the V_GSUP voltage. The remaining errors will
come from the tolerances in the R_G1 and R_G2 resistors off-chip.
15.11 Coil Current Accuracy
The accuracy of the current flowing between the + and – coil pins of a
particular coil driver pin pair is described here.
Matching of currents between coils within the same gauge is specified in
17.11 Gauge Driver Electricals as E_CM.
The absolute accuracy of the coil current that can be driven into any coil
is determined by the accuracy of I_CM given by the equations in 15.10
Gauge Regulator Accuracy and will be a total of (E_CA + E_MAX).
Because the D/A amp is shared among all coil drivers and between both
sets of drivers in the full H-bridge drivers, there will be no difference in
the magnitude of the current when the magnitude register value remains
constant and only the polarity bit is changed in a coil driver.
Technical Data
Gauge Drivers
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MC68HC05V12 — Rev. 2.0