mc33702 Freescale Semiconductor, Inc, mc33702 Datasheet - Page 15

• Manufacturer Part Number: mc33702
• Description: 3.0 A Switch-mode Power Supply With Linear Regulator
• Manufacturer: Freescale Semiconductor, Inc

cannot be cleared during the Closed Window time, which is
50% of the total watchdog period. When the watchdog is
cleared, the timer is reset and starts a new time-out period. If
the watchdog is not cleared during the Open Window time, the
RESET
RC components of the RT timer plus 10 ms.
MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA
When the Window Watchdog function is selected, the timer
Table 1. Watchdog Programming Command Byte
No Watchdog Clear Allowed
50% of Watchdog Period
will become active (LOW) for a time determined by the
Notes
0
0
0
0
0
0
0
0
0
0
Address
12.
Watchdog Closed
Timing Selected via 1
1
1
1
1
1
1
1
1
1
1
Timing Selected via I
The Watchdog feature will be turned
ON automatically after receiving any
other valid command byte changing
watchdog time.
Figure 9. Watchdog Operation
1
1
1
1
1
1
1
1
1
1
Window Open for Watchdog Clear
(as a 2nd Command Byte)
0
0
0
0
0
0
0
0
0
0
Time-Out Watchdog
Window Watchdog
0
0
1
1
1
1
1
1
1
1
Watchdog Period
Watchdog Period
Value
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
0
0
1
1
2
2
C Bus – See Table 1
C Bus – See Table 1
Freescale Semiconductor, Inc.
0
0
0
1
0
1
0
1
0
1
for Watchdog Clear
For More Information On This Product,
Window Open
1st Command
WD 1280 ms
WD 1280 ms
WD 320 ms
WD 320 ms
WD 80 ms
WD 20 ms
WD 80 ms
WD 20 ms
(Note 12)
WD OFF
WinOFF
WinOFF
WinOFF
WinOFF
Action
WinON
WinON
WinON
WinON
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EN1 and EN2 Control Pins
function and selection of the Power Sequencing mode
concurrently.
Power Sequencing mode selection.
and both can withstand a short circuit to the supply voltage,
6.0 V.
Power Sequencing Modes
supply IC is in compliance with the Motorola Power QUICC and
other 32-bit microprocessor requirements. When the input
voltage is applied, the switcher and linear regulator outputs
follow the supply rail voltage during power-up and power-down
in the limits given by the microcontroller power sequencing
specification, illustrated in
possible power sequencing modes, Standard and Inverted, as
explained in more detail below. The third mode of operation is
Power Sequencing Disabled.
V Start-Up
Max. Lead
V = 2.0 V
Slope
These two pins permit positive logic control of the Enable
Both EN1 and EN2 pins have internal pull-down resistors
The power sequencing of the two outputs of this power
1.0 V/ms
(typ.)
V Start-Up
EN1
Figure 10. Standard Power Up/Down Sequence
Figure 11. Standard Power Up/Down Sequence
0
0
1
1
3.3 V Input Supply (I/O Voltage)
Table 2. Operating Mode Selection
Table 2
3.3 V I/O Voltage (V
5.0 V Input Supply
1.8 V Core Voltage
in +3.3 V Supply System
in +5.0 V Supply System
Max. Lead
EN2
Max. Lag
1.8 V Core Voltage
V = 2.0 V
V = 0.4 V
0
1
0
1
depicts the EN1 and EN2 function and
Figures 10
LDO
)
Standard Power Sequencing
Inverted Power Sequencing
Max. Lag
V = 0.4 V
Max. Lag
No Power Sequencing
V = 0.4 V
Regulators Disabled
Regulators Enabled,
through 12. There are two
(V
Operating Mode
OUT
)
Max. Lead
Max. Lead
V = 2.0 V
V = 2.0 V
33702
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