IC-MSB_17 Datasheet, PDF(20/32 Page) IC-Haus GmbH

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IC-MSB_17 Datasheet, PDF (20/32 Pages) IC-Haus GmbH – SIN/COS SIGNAL CONDITIONER

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iC-MSBSAFETY, iC-MSB2

SIN/COS SIGNAL CONDITIONER WITH 1Vpp DRIVER

INPUT CONFIGURATION

Rev F3, Page 20/32

All input stages are configured as instrumentation am-

plifiers and thus directly suitable for differential input

signals. Referenced input signals can be processed as

an option; in this mode input X2 acts as a reference.

Both current and voltage signals can be processed as

input signals, selected using RIN12(0) and RIN0(0).

PXi

VP1

NXi

VREFI

INMODE

BIASEX

0.5 V

OR x OF x

0.25 V

0.05 x V(ACO)

VDC

VN1

VREFin

PCHx

NCHx

VPAH

VDCx

Figure 2: Signal conditioning input circuit.

Current Signals

In I Mode an input resistor Rin() becomes active at each

input pin, converting the current signal into a voltage

signal. Input resistance Rin() consists of a pad wiring

resistor and resistor Rui() which is linked to the ad-

justable bias voltage source VREFin(). The following ta-

ble shows the possible selections, with Rin() giving the

typical resulting input resistance (see Electrical Char-

acteristics for tolerances). The input resistor should be

set in such a way that intermediate potentials VDC1

and VDC2 lie between 125 mV and 250 mV (verifiable

in Calibration Mode 2).

Note: The input circuit is not suitable for back-to-back

photodiodes.

Voltage Signals

In V Mode an optional voltage divider can be selected

which reduces unacceptably large input amplitudes to

approx. 25%. The circuitry is equivalent to the resistor

chain in I Mode; the pad wiring resistor is considerably

larger here, however.

For sensors whose offset calibration is to be propor-

tional to an external DC voltage source the reference

source can be selected using BIASEX; for all other

sensors BIASEX should be set to â00â.

RIN12

RIN0

Code

â000

â010

â100

â110

1â1

0â1

Notes

Adr 0x0E, bit 3:0

Adr 0x13, bit 3:0

Nominal Rin() Intern Rui() I/V Mode

1.7 kâ¦

1.6 kâ¦

current input

2.5 kâ¦

2.3 kâ¦

current input

3.5 kâ¦

3.2 kâ¦

current input

4.9 kâ¦

4.6 kâ¦

current input

20 kâ¦

5 kâ¦

voltage input 4:1*

high

impedance

1 Mâ¦

voltage input 1:1

RIN0 must be set as RIN12 when using INMODE = 1

for single-ended input signals.

*) Refer to Elec.Char. No. 101 for permissible input

voltage range.

VREFin is the voltage dividerâs footpoint; input

currents may be positive or negative (Vin > VREFin,

or Vin < VREFin).

Table 18: I/V Mode and Input Resistance

BIAS12

BIAS0

Code

Notes

Adr 0x0E, bit 6

Adr 0x13, bit 6

Function

VREFI = 2.5 V

for low-side current sinks (e.g. photodiodes with

common anode at GNDS)

Note*: V(PXi) + V(NXi) < 2 x VREFin

VREFI = 1.5 V

for high-side currrent-sources (e.g. photodiodes with

common cathode at VDDS)

for voltage sources versus ground

for Wheatstone sensor bridges (e.g. iC-SM2)

for voltage sources with low-side reference

(e.g. iC-LSHB, when using BIASEX = 11)

Note*: V(PXi) + V(NXi) > 2 x VREFin

*) Relevant if using

- offset references VDC1/VDC2 (see Table 33)

- the input voltage divider (see Table 18)

- sum control mode (see Table 44)

Table 19: Reference Voltage

BIASEX

Code

00*

Notes

Adr 0x0D, bit 7:6

VREFin

Pin function of X2

internal

Input Index- (negative zero signal)

internal

Output of VREFin12*

external

Input for external reference**:

V(X2) replaces VREFI

*) Do not load, buffering recommended

**) See Elec. Char. Nos. 205 and 206

Table 20: Input Reference Selection

INMODE

Code

Note

Adr 0x03, bit 2

Function

Differential input signals

Single-ended input signals *

* Input X2 is reference for all inputs.

Table 17: Input Signal Mode

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