NSC LM3704XDMMX-232, LM3704XDMMX-220, LM3704XDMM-463, LM3704XDBPX-463, LM3704XDBPX-232 Datasheet

LM3704/LM3705
Microprocessor Supervisory Circuits with Power Fail
Input, Low Line Output and Manual Reset

General Description

The LM3704/LM3705 series of microprocessor supervisory
circuits provide the maximum flexibility for monitoring power
supplies and battery controlled functions in systems without
backup batteries. The LM3704/LM3705 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

CC

of

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

CC

.

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.

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 (LM3704) or RESET (LM3705) outputs
n Precision supply voltage monitor
n Factory programmable Reset Timeout Delay
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

CC

(RESET option only)

n 28 µA VCCsupply current

Applications

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

Typical Application

10136903

July 2002

LM3704/LM3705 Microprocessor Supervisory Circuits with Power Fail Input, Low Line Output and

Manual Reset

© 2002 National Semiconductor Corporation DS101369 www.national.com

Connection Diagram

MSOP-10

Top View

(looking from the coating side)

micro SMD 9 Bump Package

BPA09

10136902

10136901

Pin Description

Pin No.

Name Function

micro

SMD

MSOP

A1 2 MR

Manual-Reset input. When MR is less than V

MRT

(Manual Reset Threshold)

RESET/RESET is engaged.

B1 1 V

CC

Power Supply input.

C1 10 RESET

Reset Logic Output. Pulses low for tRP(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 tRPafter either VCCrises above the reset threshold, or after MR input rises above
V

MRT

(LM3704 only).

RESET Reset Logic Output. RESET is the inverse of RESET (LM3705 only).

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

PFT

, PFO goes low; otherwise, PFO

remains high.

C3 7 LLO

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

B3 5 GND Ground reference for all signals.

A3 4, 6 NC No Connect.

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

PFT

(Power-Fail Reset Threshold),

the PFO goes low; otherwise, PFO remains high.

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

LM3704/LM3705

www.national.com 2

Block Diagram

10136926

LM3704/LM3705

www.national.com3

Ordering Information

10136904

*

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

LM3704/LM3705

Part Number Output

Reset Timeout

Period

Package

Package

Marking

MSOP

micro

SMD

LM3704XCBP-308 totem-pole 200ms x %%I4

LM3704XCBPX-308 totem-pole 200ms x %%I4

LM3704XCMM-308 totem-pole 200ms x R35B

LM3704XCMMX-308 totem-pole 200ms x R35B

LM3705XCBP-308 totem-pole 200ms x %%I5

LM3705XCBPX-308 totem-pole 200ms x %%I5

LM3705XCMM-308 totem-pole 200ms x R36B

LM3705XCMMX-308 totem-pole 200ms x R36B

%% is the datecode and will vary with time.

Table Of Functions

Part

Number

Active

Low

Reset

Active

High

Reset

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

Reset

Timeout

Period

Manual

Reset

Power Fail

Comparator

Low
Line

Output

LM3704 x X, Y

*

Customized x x x

LM3705 x X Customized x x x

*

= available upon request. Contact National

LM3704/LM3705

www.national.com 4

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Supply Voltage (V

CC

) −0.3V to 6.0V

All Other Inputs −0.3V to V

CC

+ 0.3V

ESD Ratings (Note 2)

Human Body Model
Machine Model

1.5kV
150V

Power Dissipation (Note 3)

Operating Ratings (Note 1)

Temperature Range −40˚C ≤ T

J

≤ 85˚C

LM3704/LM3705 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

CC

= +2.2V to 5.5V.

Symbol Parameter Conditions Min Typ Max Units

POWER SUPPLY

V

CC

Operating Voltage
Range: V

CC

LM3704 1.0 5.5

V

LM3705 1.2 5.5

I

CC

VCCSupply
Current

All inputs = VCC; all outputs floating 28 50 µA

RESET THRESHOLD

V

RST

Reset Threshold VCCfalling −0.5

−2

V

RST

+0.5

+2

%

V

CC

falling: TA= 0˚C to 70˚C −1.5 +1.5

V

RSTH

Reset Threshold
Hysteresis

0.0032•V

RST

mV

t

RP

Reset Timeout
Period

Reset Timeout Period = A
Reset Timeout Period = B
Reset Timeout Period = C
Reset Timeout Period = D

1

20

140

1120

1.4
28

200

1600

2

40

280

2240

ms

t

RD

VCCto Reset
Delay

VCCfalling at 1mV/µs 20 µs

RESET (LM3705)

V

OL

RESET V

CC

>

2.25V, I

SINK

= 900µA 0.3

VV

CC

>

2.7V, I

SINK

= 1.2mA 0.3

V

CC

>

4.5V, I

SINK

= 3.2mA 0.4

V

OH

RESET V

CC

>

1.2V, I

SOURCE

= 50µA 0.8 V

CC

V

V

CC

>

1.8V, I

SOURCE

= 150µA 0.8 V

CC

V

CC

>

2.25V, I

SOURCE

= 300µA 0.8 V

CC

V

CC

>

2.7V, I

SOURCE

= 500µA 0.8 V

CC

V

CC

>

4.5V, I

SOURCE

= 800µA VCC− 1.5V

I

LKG

Output Leakage
Current

V

RESET

= 5.5V 1.0 µA

RESET (LM3704)

V

OL

RESET V

CC

>

1.0V, I

SINK

= 50µA 0.3

V

V

CC

>

1.2V, I

SINK

= 100µA 0.3

V

CC

>

2.25V, I

SINK

= 900µA 0.3

V

CC

>

2.7V, I

SINK

= 1.2mA 0.3

V

CC

>

4.5V, I

SINK

= 3.2mA 0.4

V

OH

RESET V

CC

>

2.25V, I

SOURCE

= 300µA 0.8 V

CC

V

CC

>

2.7V, I

SOURCE

= 500µA 0.8 V

CC

V

CC

>

4.5V, I

SOURCE

= 800µA VCC− 1.5V

LM3704/LM3705

www.national.com5

LM3704/LM3705 Series Electrical Characteristics (Continued)

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

CC

= +2.2V to 5.5V.

Symbol Parameter Conditions Min Typ Max Units

PFI/MR

V

PFT

PFI Input
Threshold

1.200 1.225 1.250 V

V

MRT

MR Input
Threshold

MR, Low

0.8

V

MR, High

2.0

V

PFTH

/

V

MRTH

PFI/MR Threshold
Hysteresis

PFI/MR falling: V

CC=VRST MAX

to 5.5V 0.0032•V

RST

mV

I

PFI

Input Current (PFI
only)

−75 75 nA

R

MR

MR Pull-up
Resistance

35 56 75 kΩ

t

MD

MR to Reset
Delay

12 µS

t

MR

MR Pulse Width 25 µS

PFO, LLO

V

OL

PFO, LLO Output
Voltage

V

CC

>

2.25V, I

SINK

= 900µA 0.3

V

V

CC

>

2.7V, I

SINK

= 1.2mA 0.3

V

CC

>

4.5V, I

SINK

= 3.2mA 0.4

V

OH

V

CC

>

2.25V, I

SOURCE

= 300µA 0.8 V

CC

V

CC

>

2.7V, I

SOURCE

= 500µA 0.8 V

CC

V

CC

>

4.5V, I

SOURCE

= 800µA VCC− 1.5V

LLO OUTPUT

V

LLOT

LLO Output
Threshold
(V

LLO−VRST,VCC

falling)

1.01

•

V

RST

1.02•V

RST

1.03•V

RST

V

V

LLOTH

Low-Line
Comparator
Hysteresis

0.0032

•

V

RST

mV

t

CD

Low-Line
Comparator Delay

VCCfalling at 1mV/µs 20 µs

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device
is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.
The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the
listed conditions.

Note 2: The Human Body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200pF capacitor discharged
directly into each pin.

Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, T

J

(MAX), the junction-to-ambient thermal resistance, θ

J-A

,

and the ambient temperature, T

A

. The maximum allowable power dissipation at any ambient temperture is calculated using:

Where the value of θ

J-A

for the MSOP-10 package is 195˚C/W in a typical PC board mounting and the micro SMD package is 220˚C/W.

LM3704/LM3705

www.national.com 6