LP3809
Micro-Power Voltage Detectors,
Reset Of MCU With Delay Time
General Description
The LP3809 is a micro-power voltage
detector supervising the power supply
voltage level for microprocessors (µP) or
digital systems. It provides internally fixed
threshold levels with 0.1V per step ranging
from 1.2V to 5V, which covers most digital
applications. It features low supply current of
3µA. The LP3809 performs supervisory
function by sending out a reset signal
whenever the VDD voltage falls below a
preset threshold level. This reset signal will
last the whole period before VDD recovering.
Once VDD recovered upcrossing the
threshold level, the reset signal will be
released after a certain delay time. Available
in the 5-lead of SOT-23 packages.
Features
Built-in Recovery Delay Include 210ms
Internally Fixed Threshold 1.2V to 5V in
0.1V Step
No External Components Required
High Accuracy 1.5%
Low Supply Current 3 A
Low Functional Supply Voltage 0.9V
N-Channel Open-Drain output
Quick Start-Up
Applications
Computers
CPU/MCU/DSP
Portable
Battery-Powered Equipment
Pin Configurations
Ordering Information
LP3809□ -
□ □ □ □ □
F:PB-Free
Package
B3: SOT-23
Output Voltage:
12: 1.2V
13: 1.3V
Pin No.
Type A
Type B
SOT-23
1
RESET
GND
2
GND
RESET
3
VDD
VDD
Type
A: Type A
B: Type B
50: 5.5V
Typical Application Circuit
Note:
1. Output Voltage range from 1.2V to 5.0V in
0.1V increments.
2. 2.7V output order is LP3809A-27B3F.
LP3809-datasheet
Oct.-2004
1-1
LP3809
Functional Pin Description
Pin Name Pin Function
GND
RESET
VDD
Ground
Active Low Open-Drain Reset Output
Power Pin
Function Block Diagram
Absolute Maximum Ratings
Supply Input Voltage---------------------------------------------------------------------------------------------------6V
Power Dissipation, PD @ TA = 25°C
SOT-23 --------------------------------------------------------------------------------------------------------------------400mW
Package Thermal Resistance
SOT-23,
θJA
-------------------------------------------------------------------------------------------------------------250°C/W
ESD Susceptibility
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------2kV
MM(Machine-Mode)-----------------------------------------------------------------------------------------------------200V
Recommended Operating Conditions
Supply Input Voltage-----------------------------------------------------------------------------0.3V to 6V
Operation Ambient Temperature Range------------------------------------------------−40°C to 85°C
Electrical Characteristics
Parameter
Quiescent Current
Reset Threshold
Threshold Voltage Accuracy
VDD Drop to Reset Delay
Reset Active Time
RESET Output Voltage Low
Thermal Shutdown
Temperature
Symbol
IQ
VTH
ΔVTH
Trd
LP3809A/B
VOL
TSD
Drop = VTH -125mV
VDD
≥
1.02×VTH
3 = VDD < VTH ISINK
>3.5mA
Test Conditions
VEN
≥
1.2V, IOUT =
0mA
TA = 27°C
1.2
-1.5
20
210
0.4
165
Min
Typ
3
1.5
1.5
Max
Units
μA
V
%
uS
mS
V
°C
LP3809-datasheet
Oct.-2004
2-2
MCU
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