ADVANCE INFORMATION, COMPANY CONFIDENTIAL
PI4S809/803
µP Supervisor Circuits
Features
•
Precision supply-voltage monitor
- 4.63V (PI4S8xxL)
- 4.38V (PI4S8xxM)
- 3.08V (PI4S8xxT)
- 2.93V (PI4S8xxS)
- 2.63V (PI4S8xxR)
- 2.32V (PI4S8xxZ)
- 2.20V (PI4S8xxY)
200ms reset pulse width
Reset Output Signal for Watchog and Power Abnormal,
Manual Reset
Reset Push-Pull output (PI4S809)
Voltage monitor for power-fail or low battery warning
Guaranteed RESET/RESET valid at V
CC
= 1.2V
Packaging: 3-pin SOT-23
Description
The PI4Sxxx family microprocessor (µP) supervisory circuits
are targeted to improve reliability and accuracy of power-supply
circuitry in µP systems. These devices reduce the complexity and
number of components required to monitor power-supply and
battery functions.
The main functions are:
• Asserting reset output during power-µp, power-down and
brownout conditions for µP systems.
• Detecting power failure or low-battery conditions with a 1.25V
threshold detector.
• Watchdog functions.
• Manual reset.
•
•
•
•
•
•
Applications
• Power-supply circuitry in µP systems.
Block Diagram
V
CC
Reset Generator
200ms
RESET
V
REF
GND
Pin Configuration
GND
1
2
V
CC
RESET
3
PI74S803
PI74S809
1
P-0.2
02/24/05
ADVANCE INFORMATION, COMPANY CONFIDENTIAL
PI4S809/803
µP Supervisor Circuits
Pin Description (Table 2.)
Pin Name
V
CC
GND
RESET
Type
Power
Description
Power Supply:
Reset is asserted when V
CC
drops below the Reset Threshold Voltage (V
RST
). Reset
remains asserted until V
CC
rises abouv VRES and keep asserted for the duration for the Reset Timeout
Period (t
RS
) once V
CC
rises above (V
RST
).
Ground Reference
for all signals
Active-Low Reset Output (Push-Pull or Open-Drain).
It goes low when V
CC
is below the reset
threshold. It remains low for about 200ms after one of the following occurs: V
CC
rises above the reset
threshold (V
RST
), the watchdog triggers a reset, or MR goes from low to high.
Ground
O
Functional Description
Reset Output
A microprocessor (µP) reset input starts the µP in a known state.
Whenever the µP is in an unknown state, it should be held in
reset. The supervisory circuits assert reset during power-up and
prevent code execution errors during power-down or brownout
conditions.
On power-up, once V
CC
reaches about 1.0V, RESET is a guaranteed
logic low of 0.4V or less. As V
CC
rises, RESET stays low. When
V
CC
rises above the reset threshold, an internal timer releases
RESET after about 200ms. RESET pulses low whenever V
CC
drops
below the reset threshold, i.e. brownout condition. If brownout
occurs in the middle of a previously initiated reset pulse, the pulse
continues for at least another 200ms. On power-down, once V
CC
falls below the reset threshold, RESET stays low and is guaranteed
to be 0.4V or less until V
CC
drops below 1.0V. Figure 4 shows the
timing relationship.
The active-high RESET output is simply the inverse of the RESET
output, and is guaranteed to be valid with V
CC
down to 1.0V.
Absolute Maximum Ratings
Storage Temperature ......................................................... -65
o
C
to
Ambient Temperature with
to +85
o
C
Supply Voltage to Ground Potential (V
CC
to GND) ............ -0.3V to +7.0V
DC Input Voltage (
All inputs except V
CC
and GND
) .............-0.3V to V
CC
+0.3V
DC Output Current (All outputs) ........................................................20mA
Power Dissipation (Depends on package) ..................................... 320mW
Power Applied ........................ -40
o
C
+150
o
C
Note:
Stresses greater than those listed under MAXIMUM
RATINGS may cause permanent damage to the device.
This is a stress rating only and functional operation of
the device at these or any other conditions above those
indicated in the operational sections of this specification
is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect reliability.
2
P-0.2
02/24/05
ADVANCE INFORMATION, COMPANY CONFIDENTIAL
PI4S809/803
µP Supervisor Circuits
DC Electrical Characteristics (Table 3)
Symbol
Description
Supply Voltage for xxxL, xxxM
V
CC
Supply Voltage for xxxT, xxxS
Supply Voltage for xxxR
Supply Voltage for xxxZ, xxxY
V
IH
V
IL
T
A
Input High Voltage
Input Low Voltage
Operating Temperature
-40
Test Conditions
Min
4.5
3.0
2.7
2.4
0.7V
CC
0.3V
CC
85
ºC
Typ
5.0
3.3
3.0
2.5
5.5
V
Max
Unit
DC Electrical Characteristics (Table 4)
Symbol
V
CC
I
CC
V
IH
V
IL
Description
Operating Voltage Range
Supply Current
Input High Voltage
Input Low Voltage
T
A
= 25°C
xxxL
xxxM
V
RST
Reset Threshold Voltage*
T
A
= -40~85°C
xxxT
xxxS
xxxR
xxxZ
xxxY
V
RTH
Reset Threshold Hysteresis*
V
CC
varries between VRN ±5%
V
CC
≥ 4.5V I
source
=800uA
V
OH
Output High Voltage
V
CC
≥ 2.7V I
source
=500uA
V
CC
≥ 1.8V I
source
=150uA
V
CC
≥ 1.0V I
source
=40uA
V
CC
≥ 4.5V I
sink
=3.2mA
V
OL
I
LKG
V
PFT
I
PFI
Output Low Voltage
Open-Drain Ouput Leakage
Current
PFI Input Threshold
PFI Input Leakage Current
V
CC
≥ 2.7V I
sink
=1.2mA
V
CC
≥ 1.0V I
sink
=100uA
V
CC
> V
TH(MAX)
for PI4S803
V
PFI
varies from 1.5V and 1.0V
1.2
1.25
0.4
0.3
0.3
1
1.3
±25
uA
V
nA
V
0.8xV
CC
V
CC
-1.5
V
V
RN
-1%
V
RN
-2.5%
4.514
4.271
3.003
2.857
2.564
2.262
2.145
V
RN
V
RN
4.63
4.38
3.08
2.93
2.63
2.32
2.20
50
V
CC
= 5V No Load
Test Conditions
Min
1.0
6
0.7xVCC
0.3xVcc
V
RN
+1%
V
RN
+2.5%
4.746
4.490
3.157
3.003
2.696
2.378
2.255
mV
V
Typ
Max
5.5
18
Unit
V
uA
V
V
V
V
3
P-0.2
02/24/05
Microcontroller MCU
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