Ds8102 dual delta-sigma modulator and encoder, Detailed description, Functional diagram – Rainbow Electronics DS8102 User Manual

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DS8102

Dual Delta-Sigma Modulator and Encoder

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Detailed Description

Operating Modes

The DS8102 has two operating modes: shutdown (or
power-down) mode and active mode.

Shutdown Mode

In shutdown mode, the DS8102 is in an inactive state
and consumes a minimal amount of current. No analog-
to-digital conversion or encoding is performed, and the
internal 8MHz oscillator and internal voltage reference
are disabled.

An integrated power-supply monitor holds the DS8102
in shutdown mode whenever V

≤ V

RST

. Additionally,

the RST pin can be driven low by an external compan-
ion microcontroller (such as the MAXQ3108) to force the
DS8102 to remain in shutdown mode, regardless of the
supply level at V

. This is useful in nonisolated config-

urations (when a power supply is shared between the
DS8102 and the companion microcontroller) to reduce
the current consumption of the entire system. In this
scenario, the companion microcontroller would perform
this sequence of actions when entering stop mode:

1) Drive the RST line on the DS8102 low to force the

DS8102 into shutdown mode.

2) Enter stop mode. Both the companion microcon-

troller and the DS8102 are now in their lowest cur-
rent consumption modes.

3) Exit stop mode.

4) Drive the RST line on the DS8102 high to return the

DS8102 to active mode.

Note: The RST line on the DS8102 does not include
a pullup. This means that if the RST line is not dri-
ven by a companion microcontroller, RST must be
connected to V

for proper operation. RST cannot

be left unconnected.

While the DS8102 is in shutdown mode, the levels on
the configuration input pins (APDREF, CLKSEL, G1,
and G0) can be changed if they are being driven by a
companion microcontroller instead of hardwired to V

or DGND. However, once the DS8102 enters active
mode, the levels on these pins must remain static for
proper operation.

Functional Diagram

DS8102

INTEGRATORS/

COMPARATOR

REFERENCE

BUFFER

DELTA-SIGMA MODULATOR

APDREF

REF

AN1+

MNOUT

AN1-

MANCHESTER

ENCODER

POWER

MONITOR

8MHz

OSCILLATOR

INTERNAL

REFERENCE

INTEGRATORS/

COMPARATOR

DELTA-SIGMA MODULATOR

AN0+

AN0-

G1
G0

1x, 4x,

16x, 32x

CLKSEL

CLKIO

RST

DGND

AGND