EM6152A Datasheet, PDF (1/12 Pages) EM Microelectronic - MARIN SA – 5V Automotive Regulator with Windowed Watchdog

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EM MICROELECTRONIC - MARIN SA
EM6152A
5V Automotive Regulator with Windowed Watchdog
Description
The EM6152A offers a high level of integration by combining
voltage regulation, voltage monitoring and software
monitoring using a windowed watchdog.
A comparator monitors the voltage applied at the V_IN input
comparing it with an internal voltage reference V_REF. The
power-on reset function is initialized after V_IN reaches V_REF
and takes the reset output inactive after a delay T_POR
depending on external resistance R_OSC. The reset output goes
active low when the V_IN voltage is less than V_REF. The RES
and EN outputs are guaranteed to be in a correct state for a
regulated output voltage as low as 1.2 V. The watchdog
function monitors software cycle time and execution.
If software clears the watchdog too quickly (incorrect cycle
time) or too slowly (incorrect execution) it will cause the
system to be reset. For enhanced security, the watchdog
must be serviced within an “open” time window. During the
remaining time, the watchdog time window is “closed” and a
reset will occur should a TCL pulse be received by the
watchdog during this “closed” time window. The ratio of the
open/closed window is either 33%/67% or 67%/33%.
The system ENABLE output prevents critical control functions
being activated until software has successfully cleared the
watchdog three times. Such a security could be used to
prevent motor controls being energized on repeated resets of
a faulty system.
When the microcontroller goes in stand-by mode or stops
working, no signal is received on the TCL input of the
EM6152A (version 55) and it goes into a stand-by mode in
order to save power (CAN-bus sleep detector).
In EM6152A, the voltage regulator has a low dropout voltage
and a low quiescent current of 90 μA. The quiescent current
increases only slightly in dropout prolonging battery life. Built-
in protection includes a positive transient absorber for up to
45 V (load dump) and the ability to survive an unregulated
input voltage of -42 V (reverse battery). The input may be
connected to ground or to a reverse voltage without reverse
current flowing from the output to the input.
Features
‰ Low quiescent current 90 μA
‰ -40°C to +125°C temperature range
‰ Highly accurate 5 V, 150 mA guaranteed output (actual
maximum current depends on power dissipation)
‰ Low dropout voltage, typically 250 mV at 100 mA
‰ Unregulated DC input can withstand -42 V reverse battery
and +45 V power transients
‰ Fully operational for unregulated DC input voltage up to
40 V and regulated output voltage down to 3.5 V
‰ No reverse output current
‰ Very low temperature coefficient for the regulated output
‰ Current limiting
‰ Windowed watchdog with an adjustable time windows,
guaranteeing a minimum time and a maximum time
between software clearing of the watchdog
‰ Time base accuracy ±8% (at 100ms)
‰ Sleep mode function (V55)
‰ Adjustable threshold voltage using external resistors
‰ Adjustable power on reset (POR) delay using one
external resistor
‰ Open-drain active-low RESET output
‰ Reset output guaranteed for regulated output voltage
down to 1.2 V
‰ System ENABLE output offers added security
‰ Qualified according to AEC-Q100
‰ Pin out compatible with EM6152
‰ Green SO-8 and Exposed Pad SO-16 packages (RoHS
compliant)
Applications
‰ Automotive systems
‰ Industrial
‰ Home security systems
‰ Telecom / Networking
‰ Computers
‰ Set top boxes
Typical Operating Configuration
Unregulated
Voltage
22uF +
ROSC
INPUT OUTPUT
EM6152A
ROSC
VIN
TCL
RES
VSS
EN
+
100nF 10uF ^R1
R2
5V
VDD
I/O
RES
I/O
GND
Fig. 1
Selection Table
Part Number
V_REF
EM6152A30
EM6152A50
EM6152A53
EM6152A55
1.17 V
1.52 V
1.52 V
1.275 V
Closed
Window
67%
67%
33%
67%
Open
Window
33%
33%
67%
33%
CAN-bus sleep
detector
NO
NO
NO
YES
Please refer to Fig. 4 for more information about the
open/closed window of the watchdog.
Copyright © 2006, EM Microelectronic-Marin SA
1
06/06, rev. B, Prelim.
www.emmicroelectronic.com