LM3702/LM3703 Microprocessor Supervisory Circuits with Low Line Output and Manual Reset
September 2003
LM3702/LM3703
Microprocessor Supervisory Circuits with Low Line
Output and Manual Reset
General Description
The LM3702/LM3703 series of microprocessor supervisory
circuits provide the maximum flexibility for monitoring power
supplies and battery controlled functions in systems without
backup batteries. The LM3702/LM3703 series are available
in a 9-bump micro SMD package.
Built-in features include the following:
Reset: Reset is asserted during power-up, power-down, and
brownout conditions. RESET is guaranteed down to V
CC
of
1.0V.
Manual Reset Input: An input that asserts reset when pulled
low.
Low Line Output: This early power failure warning indicator
goes low when the supply voltage drops to a value which is
2% higher than the reset threshold voltage.
n
n
n
n
n
n
n
n
No external components required
Manual-Reset input
RESET (LM3702) or RESET (LM3703) outputs
Precision supply voltage monitor
Factory programmable Reset Timeout Delay
Available in micro SMD package for minimum footprint
±
0.5% Reset threshold accuracy at room temperature
±
2% Reset threshold accuracy over temperature
extremes
n
Reset assertion down to 1V V
CC
(RESET option only)
n
28 µA V
CC
supply current
Applications
n
n
n
n
Embedded Controllers and Processors
Intelligent Instruments
Automotive Systems
Critical µP Power Monitoring
Features
n
Standard Reset Threshold voltage: 3.08V
n
Custom Reset Threshold voltages: For other voltages
between 2.2V and 5.0V in 10mV increments, contact
National Semiconductor Corp.
Typical Application
20011503
© 2003 National Semiconductor Corporation
DS200115
www.national.com
LM3702/LM3703
Connection Diagram
Top View
(looking from the coating side)
micro SMD 9 Bump Package
BPA09
20011501
Pin Descriptions
Bump No.
A1
B1
C1
Name
MR
V
CC
RESET
Function
Manual-Reset input. When MR is less than V
MRT
(Manual Reset Threshold)
RESET/RESET is engaged.
Power Supply input.
Reset Logic Output. Pulses low for t
RP
(Reset Timeout Period) when triggered, and stays
low whenever V
CC
is below the reset threshold or when MR is below V
MRT
. It remains low
for t
RP
after either V
CC
rises above the reset threshold, or after MR input rises above
V
MRT
(LM3702 only).
Reset Logic Output. RESET is the inverse of RESET (LM3703 only).
Low-Line Logic Output. Early Power-Fail warning output. Low when V
CC
falls below V
LLOT
(Low-Line Output Threshold). This output can be used to generate an NMI (Non-Maskable
Interrupt) to provide an early warning of imminent power-failure.
Ground reference for all signals.
No Connect.
No Connect. Test input used at factory only. Leave floating.
RESET
C3
LLO
B3
A2, A3, C2
B2
GND
NC
NC
www.national.com
2
LM3702/LM3703
Block Diagram
20011505
3
www.national.com
LM3702/LM3703
Ordering Information
20011504
*For other voltages between 2.2V and 5.0V, please contact National Semiconductor sales office.
LM3702/LM3703
Part Number
LM3702XCBP-308
LM3702XCBPX-308
LM3703XCBP-308
LM3703XCBPX-308
LM3703XDBP-308
LM3703XDBPX-308
LM3702YABP-308
LM3702ABPX-308
LM3702YDBP-220
LM3702YDBPX-220
%% is the datecode and will vary with time.
Output
totem-pole
totem-pole
totem-pole
totem-pole
totem-pole
totem-pole
open-drain
open-drain
open-drain
open-drain
Reset
Timeout
Period
200ms
200ms
200ms
200ms
1600ms
1600ms
1.4ms
1.4ms
1600ms
1600ms
Package
Marking
%%I2
%%I2
%%I3
%%I3
%%124
%%124
%%131
%%131
%%125
%%125
Table Of Functions
Part
Number
LM3702
LM3703
* = available upon request. Contact National
Active
Low
Reset
x
Active
High
Reset
x
Output
(X = totem-pole)
(Y = open-drain)
X, Y*
X
Reset
Timeout
Period
Customized
Customized
Manual
Reset
x
x
Low
Line
Output
x
x
www.national.com
4
LM3702/LM3703
Absolute Maximum Ratings
(Note 1)
Power Dissipation
(Note 3)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
CC
)
All Other Inputs
ESD Ratings (Note 2)
Human Body Model
Machine Model
−0.3V to 6.0V
−0.3V to V
CC
+ 0.3V
1.5kV
150V
Operating Ratings
(Note 1)
Temperature Range
−40˚C
≤
T
J
≤
85˚C
LM3702/LM3703 Series Electrical Characteristics
Limits in the standard typeface are for T
J
= 25˚C and limits in
boldface type
apply over full operating range. Unless otherwise
specified: V
CC
= +2.2V to 5.5V.
Symbol
V
CC
I
CC
Parameter
Operating Voltage
Range: V
CC
V
CC
Supply
Current
Reset Threshold
LM3702
LM3703
All inputs = V
CC
; all outputs floating
Conditions
Min
1.0
1.2
28
Typ
Max
5.5
5.5
50
Units
POWER SUPPLY
V
µA
RESET THRESHOLD
V
RST
V
CC
falling
V
CC
falling: T
A
= 0˚C to 70˚C
V
RSTH
t
RP
Reset Threshold
Hysteresis
Reset Timeout
Period
Reset
Reset
Reset
Reset
Timeout
Timeout
Timeout
Timeout
Period
Period
Period
Period
=
=
=
=
A
B
C
D
1
20
140
1120
−0.5
−2
−1.5
0.0032
•
V
RST
1.4
28
200
1600
20
2
40
280
2240
V
RST
+0.5
+2
+1.5
mV
%
ms
t
RD
V
CC
to Reset
Delay
RESET
V
CC
falling at 1mV/µs
µs
RESET (LM3703)
V
OL
V
CC
>
2.25V, I
SINK
= 900µA
V
CC
>
2.7V, I
SINK
= 1.2mA
V
CC
>
4.5V, I
SINK
= 3.2mA
V
OH
RESET
V
CC
>
1.2V, I
SOURCE
= 50µA
V
CC
>
1.8V, I
SOURCE
= 150µA
V
CC
>
2.25V, I
SOURCE
= 300µA
V
CC
>
2.7V, I
SOURCE
= 500µA
V
CC
>
4.5V, I
SOURCE
= 800µA
I
LKG
Output Leakage
Current
RESET
V
RESET
= 5.5V
0.8 V
CC
0.8 V
CC
0.8 V
CC
0.8 V
CC
V
CC
− 1.5V
1.0
µA
V
0.3
0.3
0.4
V
RESET (LM3702)
V
OL
V
CC
>
1.0V, I
SINK
= 50µA
V
CC
>
1.2V, I
SINK
= 100µA
V
CC
>
2.25V, I
SINK
= 900µA
V
CC
>
2.7V, I
SINK
= 1.2mA
V
CC
>
4.5V, I
SINK
= 3.2mA
V
OH
RESET
V
CC
>
2.25V, I
SOURCE
= 300µA
V
CC
>
2.7V, I
SOURCE
= 500µA
V
CC
>
4.5V, I
SOURCE
= 800µA
0.8 V
CC
0.8 V
CC
V
CC
− 1.5V
0.3
0.3
0.3
0.3
0.4
V
5
www.national.com
单片机
