SAP5SD-A-G1-T Datasheet, PDF (28/63 Pages) List of Unclassifed Manufacturers – Universal Actuator-Sensor Interface IC

SAP5S / SAP51
Universal Actuator-Sensor Interface IC
4 Detailed Functional Description
4.1. Power Supply
The power supply block provides a sensor supply, which is inductively decoupled from the AS-i bus voltage, at
pin UOUT. The decoupling is realized by an Electronic Inductor circuit, which basically consists of a current
source and a controlling low pass. The time constant of the low pass that has influence to the resulting input
impedance at pin UIN, can be adjusted by an external capacitor at pin CDC.
A second function of the power supply block is to generate a regulated 5V supply for operation of the internal
logic and some analog circuitry. The voltage is provided at pin U5R an can be used to supply external circuitry
as well, as long as the current requirements stay within in the specified limits (Table 2 at page 10). Because
the 5V supply is generated out of the decoupled sensor supply at UOUT, the current drawn at U5R has to be
subtracted from the total available load current at UOUT.
The power supply dissipates the major amount of power:
Ptot = V_Drop* (I_UOUT + I_5V) + (V_UOUT-5V) * I_5V
In total, the power dissipation shall not exceed the specified values of chapter 1.1.
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.
4.1.1. Voltage Output Pins UOUT and U5R
Table 12: Properties of voltage output pins UOUT and U5R
Symbol Parameter
Min
V_UIN Positive supply voltage for IC
16
operation
V_DROP Voltage drop from pin LTGP to pin
5.2
UOUT
Max
Unit
34
V
7.8
V
V_UOUT
V_UOUTp
t_UOUTp
V_U5R
I_UOUT
UOUT output supply voltage
UOUT output voltage pulse deviation
UOUT output voltage pulse deviation
width
5V supply voltage
UOUT output supply current
V_UIN- V_DROPmax V_UIN- V_DROPmin
V
1.5
V
2
ms
4.75
5.25
V
0
55
mA
I_5V
U5R output supply current
0
4
mA
I_o
Total output current I_UOUT + I_5V
60
mA
C_BUOUT Blocking capacitance at UOUT
10
470
µF
C_B5V Blocking capacitance at U5R
100
nF
1 _{Parameter copied from Table 2 at page 10}
2 _{The actual voltage drop increases with increasing load current at Uout}
3 _{CUOUT = 10µF, output current switches from 0 to IUOUTmax and vice versa}
Note
1
V_UIN > 22V
2
IUOUTmax
3
3
I_U5R = 0
Uin>24V
Data Sheet
July 17, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 3.1
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