General Note

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Rev C, 4/27/2023

Page 30

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FlexSense® I-Series Programmable

Incremental Encoder

FS210/FS310 Datasheet

Other Registers

The FS210/FS310 contains two registers that selectively power down portions of the quadrature-track and index-track

signal-path circuitry: the Transimpedance Amplifier Enable (TIAE) and Comparator/Buffer Enable Register (CBFEZ) registers.

There are two situations in which it might be desirable to modify the contents of these registers from their power-on

defaults in order to reduce the supply current consumed by the device:

• If the device is deployed in a system whose code wheel does not contain an index track, then TIAE and CBFEZ can be

modified to turn off the index-track transimpedance amplifier and comparator.

• If the device is in a system in which QCFG is configured only for analog outputs and/or uninterpolated digital

outputs, then CBFEZ can be modified to turn off the interpolated quad-track comparators.

In all other cases, the contents of TIAE and CBFEZ should not be modified from their power-on defaults.

The FS210/FS310 also contains a Miscellaneous Control Register (MISC), which can be used to enable the preventive-

maintenance outputs on the IPTAT, AMPL2_P, and AMPL2_N pins. If these outputs are enabled, the IPTAT pin sinks a

current that is first-order proportional to absolute temperature and is nominally equal to 10μA at 25°C, and the AMPL2_P

and AMPL2_N pins source currents whose difference is the sum of the squares of the analog quadrature-track differential

output voltages (which should be constant if the device is configured properly and the system has no mechanical-integrity

issues).

Transimpedance Amplifier Enable Register (TIAE: [0x088A])

Table 32. TIAE register definition

MSB

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

LSB

RSVD

ZTIAE

RSVD

Table 33. TIAE field description

Bits

Description

ZTIAE

Index-track transimpedance-amplifier enable bit:

1:

Enable index-track transimpedance amplifier (power-on default)

0:

Disable index-track transimpedance amplifier

RSVD

Reserved; do not modify from power-on default value (1)