NSC LP3470M5-4.38, LP3470M5-4.00, LP3470M5-3.08, LP3470M5-2.63, LP3470IM5X-4.63 Datasheet
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June 1999
LP3470
Tiny Power On Reset Circuit
General Description
The LP3470 is a micropower CMOS voltage supervisory circuit designed to monitor power supplies in microprocessor (µP) and other digital systems. It provides maximum adjustability for power-on-reset (POR) and supervisory functions. It is available in the following six standard reset threshold voltage (VRTH) options: 2.63V, 2.93V, 3.08V, 4.00V, 4.38V, and 4.63V. If other voltage options between 2.4V and 5.0V are desired please contact your National Semiconductor representative.
The LP3470 asserts a reset signal whenever the VCC supply voltage falls below a reset threshold. The reset time-out period is adjustable using an external capacitor. Reset remains asserted for an interval (programmed by an external capacitor) after VCC has risen above the threshold voltage.
The device is available in the tiny SOT23-5 package.
Key Specifications
n±1% Reset Threshold Accuracy Over Temperature
nStandard Reset Threshold Voltages: 2.63V, 2.93V, 3.08V, 4.00V, 4.38V, and 4.63V
nCustom Reset Threshold Voltages: For other voltages between 2.4V and 5.0V contact your National Semiconductor representative
nVery Low Quiescent Current (16 µA typical)
nGuaranteed Reset valid down to VCC=0.5V
Features
nTiny SOT23-5 Package
nOpen Drain Reset Output
nProgrammable Reset Timeout Period Using an External Capacitor
nImmune to Short VCC Transients
Applications
nCritical µP and µC Power Monitoring
nIntelligent Instruments
nComputers
nPortable/Battery-Powered Equipments
Pin Configuration and Basic Operating Circuit
Pin Configuration |
Basic Operating Circuit |
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DS100016-2
Top View
See NS Package Number
MA05B
DS100016-1
Circuit Reset On Power Tiny LP3470
© 1999 National Semiconductor Corporation |
DS100016 |
www.national.com |
Ordering Information
Operating |
Order |
Nominal |
Package |
Package |
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Temperature |
VRTH (V) |
Supplied As |
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Number |
Marking |
Type |
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Range |
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LP3470M5-2.63 |
2.63 |
D25B |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470M5X-2.63 |
2.63 |
D25B |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470M5-2.93 |
2.93 |
D26B |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470M5X-2.93 |
2.93 |
D26B |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470M5-3.08 |
3.08 |
D28B |
SOT23-5 |
250 Units on Tape and Reel |
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−20ÊC to |
LP3470M5X-3.08 |
3.08 |
D28B |
SOT23-5 |
3k Units on Tape and Reel |
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+85ÊC |
LP3470M5-4.00 |
4.00 |
D29B |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470M5X-4.00 |
4.00 |
D29B |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470M5-4.38 |
4.38 |
D30B |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470M5X-4.38 |
4.38 |
D30B |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470M5-4.63 |
4.63 |
D31B |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470M5X-4.63 |
4.63 |
D31B |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470IM5-2.63 |
2.63 |
D25C |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470IM5X-2.63 |
2.63 |
D25C |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470IM5-2.93 |
2.93 |
D26C |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470IM5X-2.93 |
2.93 |
D26C |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470IM5-3.08 |
3.08 |
D28C |
SOT23-5 |
250 Units on Tape and Reel |
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−40ÊC to |
LP3470IM5X-3.08 |
3.08 |
D28C |
SOT23-5 |
3k Units on Tape and Reel |
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+85ÊC |
LP3470IM5-4.00 |
4.00 |
D29C |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470IM5X-4.00 |
4.00 |
D29C |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470IM5-4.38 |
4.38 |
D30C |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470IM5X-4.38 |
4.38 |
D30C |
SOT23-5 |
3k Units on Tape and Reel |
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LP3470IM5-4.63 |
4.63 |
D31C |
SOT23-5 |
250 Units on Tape and Reel |
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LP3470IM5X-4.63 |
4.63 |
D31C |
SOT23-5 |
3k Units on Tape and Reel |
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www.national.com |
2 |
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.
VCC Voltage |
−0.3V to +6V |
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Reset |
Voltage |
−0.3V to +6V |
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10 mA |
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Output Current |
(Reset) |
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Operating Temperature Range |
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LP3470 |
−20ÊC to +85ÊC |
LP3470I |
−40ÊC to +85ÊC |
Junction Temperature (TJmax) |
125ÊC |
Power Dissipation (TA = 25ÊC) (Note |
300 mW |
2) |
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θJA (Note 2) |
280ÊC/W |
Storage Temp. Range |
−65ÊC to +150ÊC |
Lead Temp. (Soldering, 5 sec) |
260ÊC |
ESD Rating (Note 3) |
2 kV |
Electrical Characteristics
Limits in standard typeface are for TJ = 25ÊC, and limits in boldface type apply over the full operating temperature range, unless otherwise specified. VCC = +2.4V to +5.0V unless otherwise noted.
Symbol |
Parameter |
Conditions |
Typ (Note 4) |
Min (Note 5) |
Max (Note 5) |
Units |
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VCC |
Operating Voltage Range |
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0.5 |
5.5 |
V |
ICC |
VCC Supply Current |
VCC = 4.5V |
16 |
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30 |
µA |
VRTH |
Reset Threshold Voltage |
LP3470 |
VRTH |
0.99 VRTH |
1.01 VRTH |
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(Note 6) |
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0.99 VRTH |
1.01 VRTH |
V |
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LP3470I |
VRTH |
0.99 VRTH |
1.01 VRTH |
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0.985 VRTH |
1.015 VRTH |
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VHYST |
Hysteresis Voltage (Note 7) |
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35 |
15 |
65 |
mV |
tPD |
VCC to Reset Delay |
VCC falling at 1 mV/µs |
100 |
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300 |
µs |
tRP |
Reset Timeout Period (Note |
C1 = 1 nF |
2 |
1.0 |
3.5 |
ms |
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8) |
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VOL |
Reset Output Voltage Low |
VCC = 0.5V; IOL = 30 µA |
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0.1 |
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VCC = 1.0V; IOL = 100 µA |
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0.1 |
V |
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VCC =VRTH −100 mV; I OL = 4 |
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0.4 |
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mA |
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R1 |
External Pull-up Resistor |
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20 |
0.68 |
68 |
kΩ |
ILEAK |
Reset Output Leakage |
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0.15 |
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1 |
µA |
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Current |
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6 |
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Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the device beyond its operating conditions.
Note 2: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax (Maximum Junction Temperature), θJA (Junction to Ambient Thermal Resistance), and TA (Ambient Temperature). The maximum allowable power dissipation at any temperature is PDmax = (TJmax − T A)/ θJA or the number given in the Absolute Maximum Ratings, whichever is lower.
Note 3: The Human Body Model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin.
Note 4: Typical numbers are at 25ÊC and represent the most likely parametric norm.
Note 5: Min. and Max. limits in standard typeface are 100% production tested at 25ÊC. Min. and Max. limits in boldface are guaranteed through correlation using Statistical Quality Control (SQC) methods. The limits are used to calculate National's Average Outgoing Quality Level (AOQL).
Note 6: Factory-trimmed reset thresholds are available in 50 mV increments from 2.4V to 5.0V. Contact your National Semiconductor representative.
Note 7: VHYST affects the relation between VCC and Reset as shown in the timing diagram.
Note 8: tRP is programmable by varying the value of the external capacitor (C1) connected to pin SRT. The equation is: tRP = 2000 x C1 (C1 in µF and tRP in ms).
3 |
www.national.com |
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