R
EM MICROELECTRONIC - MARIN SA
EM6152A
5V Automotive Regulator with Windowed Watchdog
Description
Features
The EM6152A offers a high level of integration by combining
voltage regulation, voltage monitoring and software
monitoring using a windowed watchdog.
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)
A comparator monitors the voltage applied at the VIN input
comparing it with an internal voltage reference VREF. The
power-on reset function is initialized after VIN reaches VREF
and takes the reset output inactive after a delay TPOR
depending on external resistance ROSC. The reset output goes
active low when the VIN voltage is less than VREF. 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.
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
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%.
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
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.
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
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).
Pin out compatible with EM6152
Green SO-8 and Exposed Pad SO-16 packages (RoHS
compliant)
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.
Applications
Automotive systems
Industrial
Home security systems
Telecom / Networking
Computers
Set top boxes
Typical Operating Configuration
Selection Table
Part Number
Closed
Window
67%
Open
Window
33%
Unregulated
Voltage
CAN-bus sleep
detector
VREF
5V
VDD
INPUT OUTPUT
+
EM6152A30
EM6152A50
EM6152A53
1.17 V
1.52 V
1.52 V
NO
NO
R1
EM6152A
100nF 10uF
67%
33%
VIN
ROSC
22uF
+
I/O
TCL
RES
33%
67%
NO
ROSC
RES
I/O
EM6152A55 1.275 V
67%
33%
YES
VSS
EN
R2
Please refer to Fig. 4 for more information about the
open/closed window of the watchdog.
GND
Fig. 1
Copyright © 2006, EM Microelectronic-Marin SA
06/06, rev. B, Prelim.
1
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