National Semiconductor LM3710, LM3711 Technical data

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LM3710/LM3711
Microprocessor Supervisory Circuits with Power Fail
Input, Low Line Output, Manual Reset and Watchdog
Timer

June 2002

LM3710/LM3711 Microprocessor Supervisory Circuits with Power Fail Input, Low Line Output,

Manual Reset and Watchdog Timer

General Description

The LM3710/LM3711 series of microprocessor supervisory
circuits provide the maximum flexibility for monitoring power
supplies and battery controlled functions in systems without
backup batteries. The LM3710/LM3711 series are available
in MSOP-10 and 9-bump micro SMD packages.

Built-in features include the following:
Reset: Reset is asserted during power-up, power-down, and

brownout conditions. RESET is guaranteed down to V

1.0V.
Manual Reset Input: An input that asserts reset when pulled

low.
Power-Fail Input: A 1.225V threshold detector for power fail

warning, or to monitor a power supply other than V
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.

Watchdog Timer: The WDI (Watchdog Input) monitors one of
the µP’s output lines for activity. If no output transition occurs
during the watchdog timeout period, reset is activated.

CC

.

CC

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.

n No external components required
n Manual-Reset input
n RESET (LM3710) or RESET (LM3711) outputs

of

n Precision supply voltage monitor
n Factory programmable Reset and Watchdog Timeout

Delays

n Separate Power Fail comparator
n Available in micro SMD package for minimum footprint

±

n

0.5% Reset threshold accuracy at room temperature

±

n

2% Reset threshold accuracy over temperature

extremes

n Reset assertion down to 1V V
n 28 µA VCCsupply current

(RESET option only)

CC

Applications

n Embedded Controllers and Processors
n Intelligent Instruments
n Automotive Systems
n Critical µP Power Monitoring

Typical Application

20011803

© 2002 National Semiconductor Corporation DS200118 www.national.com

Connection Diagram

LM3710/LM3711

MSOP-10

Top View

(looking from the coating side)

micro SMD 9 Bump Package

BPA09

20011802

20011801

Pin Descriptions

Pin No.

micro

SMD

MSOP

A1 2 MR

B1 1 V

C1 10 RESET

C2 8 PFO Power-Fail Logic Output. When PFI is below V

C3 7 LLO

B3 5 GND Ground reference for all signals.

A3 4 WDI Watchdog Input Transition Monitor: If no transition activity occurs for a period exceeding

A2 3 PFI Power-Fail Comparator Input. When PFI is less than V

B2 6, 9 NC No Connect. Test input used at factory only. Leave floating.

Name Function

Manual-Reset input. When MR is less than V

(Manual Reset Threshold)

MRT

RESET/RESET is engaged.

CC

Power Supply input.

Reset Logic Output. Pulses low for tRP(Reset Timeout Period) when triggered, and stays
low whenever V

is below the reset threshold or when MR is below V

CC

for tRPafter either VCCrises above the reset threshold, or after MR input rises above
V

(LM3710 only).

MRT

RESET Reset Logic Output. RESET is the inverse of RESET (LM3711 only).

, PFO goes low; otherwise, PFO

PFT

remains high.

Low-Line Logic Output. Early Power-Fail warning output. Low when VCCfalls below V
(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.

(Watchdog Timeout Period), reset is engaged.

t

WD

(Power-Fail Reset Threshold),

PFT

the PFO goes low; otherwise, PFO remains high.

. It remains low

MRT

LLOT

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Block Diagram

LM3710/LM3711

20011805

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Ordering Information

LM3710/LM3711

*

For other voltages between 2.2V and 5.0V, please contact National Semiconductor sales office.

20011804

LM3710/LM3711

Part Number Output

Reset Timeout

Period

Watchdog

Timeout

Period

MSOP

Package

micro

SMD

Package

Marking

LM3710XQBP-308 totem-pole 200ms 1600ms x %%IA

LM3710XQBPX-308 totem-pole 200ms 1600ms x %%IA

LM3710XQMM-308 totem-pole 200ms 1600ms x R37B

LM3710XQMMX-308 totem-pole 200ms 1600ms x R37B

LM3711XQBP-308 totem-pole 200ms 1600ms x %%IB

LM3711XQBPX-308 totem-pole 200ms 1600ms x %%IB

LM3711XQMM-308 totem-pole 200ms 1600ms x R38B

LM3711XQMMX-308 totem-pole 200ms 1600ms x R38B

%% is the datecode and will vary with time.

Table Of Functions

Part

Number

LM3710 x X, Y

LM3711 x X Customized Customized x x x

*

= available upon request. Contact National

Active

Low

Reset

Active

High

Reset

Output
(X = totem-pole)
(Y = open-drain)

*

Reset

Timeout

Period

Watchdog

Timeout

Period

Manual

Reset

Power Fail

Comparator

Low
Line

Output

Customized Customized x x x

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LM3710/LM3711

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

All Other Inputs −0.3V to V

) −0.3V to 6.0V

CC

CC

+ 0.3V

Operating Ratings (Note 1)

Temperature Range −40˚C ≤ T

≤ 85˚C

J

ESD Ratings (Note 2)

Human Body Model
Machine Model

1.5kV
150V

LM3710/LM3711 Series Electrical Characteristics

Limits in the standard typeface are for TJ= 25˚C and limits in boldface type apply over full operating range. Unless otherwise
specified: V

Symbol Parameter Conditions Min Typ Max Units

POWER SUPPLY

V

CC

I

CC

RESET THRESHOLD

V

RST

V

RSTH

t

RP

t

RD

RESET (LM3711)

V

OL

V

OH

I

LKG

RESET (LM3710)

V

OL

V

OH

= +2.2V to 5.5V.

CC

Operating Voltage
Range: V

CC

VCCSupply

LM3710 1.0 5.5

LM3711 1.2 5.5

All inputs = VCC; all outputs floating 28 50 µA

Current

Reset Threshold VCCfalling −0.5

−2

falling: TA= 0˚C to 70˚C −1.5 +1.5

V

CC

Reset Threshold
Hysteresis

Reset Timeout
Period

VCCto Reset

Reset Timeout Period = E, J, N, S
Reset Timeout Period = F, K, P, T
Reset Timeout Period = G, L, Q, U
Reset Timeout Period = H, M, R, V

1

20

140

1120

VCCfalling at 1mV/µs 20 µs

Delay

V

V

V

V

V

V

>

2.25V, I

CC

>

2.7V, I

CC

>

4.5V, I

CC

>

1.2V, I

CC

>

1.8V, I

CC

>

2.25V, I

CC

>

2.7V, I

CC

>

4.5V, I

CC

= 5.5V 1.0 µA

RESET

= 900µA 0.3

SINK

= 1.2mA 0.3

SINK

= 3.2mA 0.4

SINK

SOURCE

SOURCE

SOURCE

SOURCE

= 50µA 0.8 V

= 150µA 0.8 V

SOURCE

= 300µA 0.8 V

= 500µA 0.8 V

= 800µA VCC− 1.5V

RESET V

RESET V

Output Leakage
Current

RESET V

RESET V

>

1.0V, I

CC

>

V

1.2V, I

CC

>

V

2.25V, I

CC

>

V

2.7V, I

CC

>

V

4.5V, I

CC

>

2.25V, I

CC

>

V

2.7V, I

CC

>

V

4.5V, I

CC

= 50µA 0.3

SINK

= 100µA 0.3

SINK

= 900µA 0.3

SINK

= 1.2mA 0.3

SINK

= 3.2mA 0.4

SINK

SOURCE

SOURCE

SOURCE

= 300µA 0.8 V

= 500µA 0.8 V

= 800µA VCC− 1.5V

+0.5

V

RST

0.0032•V

RST

1.4
28

200

1600

CC

CC

CC

CC

CC

CC

+2

mV

2

40

280

2240

V

%

ms

VV

V

V

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