L9678P datasheet(169/215 Pages) STMICROELECTRONICS

No. de pieza	L9678P

Descripción Electrónicos	Automotive user configurable airbag and battery cut-off IC

PDF	215 Pages

Scroll/Zoom	100%

Fabricante Electrónico	STMICROELECTRONICS [STMicroelectronics]

Página de inicio	http://www.st.com

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169 / 215 page

DS11626 Rev 9

169/216

L9678P, L9678P-S

System voltage diagnostics

214

applies to the case of a precise reference voltage: the spread of reference voltage causes a

proportional error in the conversion output. The reference voltage of the ADC is set to 2.5 V.

The conversion time is comprised of several factors: the number of measurements loaded

into the queue, the number of samples taken for any measurement, and the various settling

times. An example of conversion time calculation for a full ADC request queue is reported in

Figure 57. The timings reported in Figure 57 are nominal ones, min/max values can be

obtained by considering the internal oscillator frequency variation reported in the DC

characteristics section.

Figure 57. ADC conversion time

GAPGPS01655

Post

ADC

Pre-

DIAGCTRL_ A

S * T_SC

DIAGCTRL_B

S * T_SC

DIAGCTRL_C

S*T_SC

DIAGCTRL_D

S*T_SC

Post- ADC = Final ADC Settling Time = 3.44 μs

IQ = Intra- Queue Settling Time = 3.5 μs

T_ SC = Single Sample Conversion Time = 2.25 μs

S = # of Samples (default = 4 for voltage only measurements)

Pre- AD C = Initial ADC Settling Time = 4.81 μs

L9678P Datasheet(PDF) 169 Page - STMicroelectronics