SAP5SD-B-G1-R datasheet(26/67 Pages) RENESAS

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SAP51 / SAP5S Datasheet

January 28, 2016

Detailed Functional Description

5.1.

Power Supply

The power supply block provides a sensor supply, which is inductively decoupled from the AS-i bus voltage, at the

UOUT pin. The decoupling is realized by an electronic inductor circuit, which basically consists of a current source

and a controlling low pass filter. The time constant of the low pass, which affects the resulting input impedance at

the LTGP pin, can be adjusted by an external capacitor at the CDC pin.

A second function of the power supply block is to generate a regulated 5V supply for operation of the internal logic

and some of the analog circuitry. The voltage is provided at the U5R pin and can be used to supply external

circuitry as well if the current requirements stay within in the specified limits (see Table 2.2). Because the 5V

supply is generated from the decoupled sensor supply at UOUT, the current drawn at U5R must be subtracted

from the total available load current at UOUT.

The power supply dissipates most of the power (see Table 5.1):

Ptot = VDROP∗ (IUOUT + I5V) + (VUOUT-5V) ∗ I5V

In total, the power dissipation must not exceed the specified values in section 2.1.

To cope with fast internal and external load changes (spikes), external capacitors at UOUT and U5R are required.

The LTGN pin defines the ground reference voltage for both UOUT and U5R.

5.1.1.

Voltage Output Pins UOUT and U5R

Table 5.1

Properties of Voltage Output Pins UOUT and U5R

PARAMETER

SYMBOL

CONDITIONS

MIN

MAX

UNIT

Positive supply voltage for SAP5 operation

VLTGP

Voltage drop from LTGP pin to UOUT pin

VDROP

VLTGP > 22V

5.2

7.8

UOUT output supply voltage

VUOUT

IUOUT = IUOUTmax

VLTGP - VDROPmax

VLTGP - VDROPmin

UOUT output voltage pulse deviation

VUOUTp

CUOUT = 10µF

1.5

UOUT output voltage pulse deviation width

tUOUTp

CUOUT = 10µF

5V supply voltage

VU5R

4.75

5.25

UOUT output supply current

IUOUT

IU5R = 0

VLTGP >24V

U5R output supply current

IU5R

Total output current IUOUT + I5V

Blocking capacitance at UOUT

CUOUT

470

µF

Blocking capacitance at U5R

CU5R

100

Parameter is also given in Table 2.2.

CUOUT = 10µF; output current switches from 0 to IUOUTmax and vice versa.

SAP5SD-B-G1-R 数据表(PDF) 26 Page - Renesas Technology Corp

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