Maxim MAX6808XR46-T, MAX6808US26-T, MAX6808US46-T, MAX6807XR46-T, MAX6808UR26-T Datasheet

General Description

The MAX6806/MAX6807/MAX6808 precision voltage
detectors are ideal for accurate monitoring of power
supplies in digital systems. They provide circuit reliabili­ty and reduce total cost by eliminating external compo­nents and adjustments.

The MAX6806/MAX6807/MAX6808 assert a reset signal
whenever the supply voltage (VCC) falls below the factory­preset, ±2% accurate threshold. Internal hysteresis
ensures stable switching. The MAX6806/MAX6807/
MAX6808 are available in 4.6V and 2.6V thresholds (2.3V
is also available for the MAX6806 only). The MAX6806 fea­tures an active-low, push-pull RESET output; the MAX6807
features an active-high, push-pull RESET output; and the
MAX6808 features an active-low, open-drain RESET out­put. RESET is valid for VCCdown to 1V (MAX6806/
MAX6808), and RESET (MAX6807) is guaranteed for V

CC

down to 1.2V.
The MAX6806/MAX6807/MAX6808 are available in

3-pin SC70, 3-pin SOT23, and 4-pin SOT143 packages.
The SOT143 package includes a manual-reset input.

Applications

Computers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable/Battery-Powered Equipment
Automotive
Bar-Code Scanners

Features

♦ Preset Reset Thresholds: 4.6V and 2.6V

(2.3V also available for MAX6806 only)

♦ ±2% Accurate Reset Thresholds
♦ Reset Output Available in Active-Low (MAX6806),

Active-High (MAX6807), and Open-Drain
(MAX6808) Versions

♦ Immune to Power-Supply Transients
♦ RESET Valid to VCC= 1.0V (MAX6806/MAX6808)
♦ 35µA Supply Current
♦ No External Components
♦ Manual Reset Available with 4-Pin SOT143

Package

♦ Miniature 3-Pin SC70, 3-Pin SOT23, and 4-Pin

SOT143 Packages

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

MAX6806/MAX6807/MAX6808

Voltage Detectors

________________________________________________________________

Maxim Integrated Products

1

19-1421; Rev 1; 4/99

PART RESET OUTPUT

Selector Guide

Ordering Information

TOP MARK

NOMINAL

V

TH-

(V)

†

MAX6806UR46-T
MAX6806UR26-T

Active-Low, Push-Pull

FZDP

FZDQ

4.6

2.6
MAX6806UR23-T
MAX6806US46-T

FZDR
KABT

2.3

4.6
MAX6806US26-T
MAX6806US23-T

KABU
KABV

2.6

2.3

†

Other reset thresholds may be available. Contact factory for availability.

TEMP. RANGE

MAX6806XR_ _-T

-40°C to +85°C

PART

Typical Operating Circuit and Pin Configurations appear at
end of data sheet.

PIN-PACKAGE

3 SC70

MAX6806US_ _-T -40°C to +85°C 4 SOT143

MAX6807US_ _-T -40°C to +85°C 4 SOT143

MAX6807XR_ _-T

-40°C to +85°C 3 SC70

MAX6808US_ _-T -40°C to +85°C 4 SOT143

MAX6808XR_ _-T

-40°C to +85°C 3 SC70

*

All devices available in tape-and-reel only, 2500 piece mini-

mum order quantity.
Note: Insert the desired number from the Selector Guide into the

blank to complete the part number. Also see Selector Guide for
top mark.

Selector Guide continued at end of data sheet.

MAX6806UR_ _-T -40°C to +85°C 3 SOT23

MAX6807UR_ _-T -40°C to +85°C 3 SOT23

MAX6808UR_ _-T -40°C to +85°C 3 SOT23

MAX6806/MAX6807/MAX6808

Voltage Detectors

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +5V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

Note1: All devices are 100% production tested at TA = +25°C, and are guaranteed by design for TA= T

MIN

to T

MAX

, as specified.

Note 2: RESET output for MAX6806/MAX6808, RESET output for MAX6807.

V

CC

to GND ..........................................................-0.3V to +6.0V

RESET, RESET to GND

(MAX6806/MAX6807) ................................-0.3V to (V

CC

+ 0.3V)

RESET to GND (MAX6808)...................................-0.3V to + 6.0V

MR to GND (SOT143 package only)....................-0.3V to + 6.0V

Input Current, V

CC

...........................................................±20mA

Output Current, RESET, RESET .......................................±20mA

Rate of Rise, V

CC

...........................................................100V/µs

Continuous Power Dissipation (T

A

= +70°C)

SOT23, SOT143 (derate 4mW/°C above +70°C) .........320mW

SC70 (derate 2.17mW/°C above +70°C) .....................174mW

Operating Temperature Range ..........................-40°C to +85°C

Storage Temperature Range.............................-65°C to +160°C

Lead Temperature (soldering, 10sec).............................+300°C

V

CC

= +3.6V, no load

VCC> V

TH+

TA= -40°C to +85°C

TA= 0°C to +70°C

VCCfalling at 1mV/µs

I

SINK

= 1.0mA, VCC= 2.0V

I

SINK

= 3.2mA, VCC= 5.0V

I

SOURCE

= 400µA, VCC= 2.0V

I

SINK

= 20µA, VCC= 1.0V

TA= +25°C, Figure 2

VCC= +5.5V, no load

I

SOURCE

= 20µA, VCC= 1.2V

TA = +25°C,
VCCfalling

CONDITIONS

V

0.7V

CC

V

IH

MR Input Threshold

0.6V

IL

kΩ40 80 120R

MR

MR Pull-Down Resistance

ppm/°C30Reset Threshold Tempco

µs30VCCto Reset Delay (Note 2)

0.4V

OL

RESET Output Voltage
(MAX6807)

V

0.8V

CC

V

OH

0.8V

CC

35 60

V

1.2 5.5

V

CC

1.0 5.5

Supply Voltage Range

V

OL

0.4

0.3

V

0.02 0.03
V

TH-

V

TH-

V

HYST

Reset Threshold Hysteresis

µA

50 80

I

CC

Supply Current

4.508 4.60 4.692

2.548 2.60 2.652 V

2.254 2.30 2.346

V

TH-

Reset Threshold

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX680_ _ _46
MAX680_ _ _26
MAX680_ _ _23

V

OH

I

SOURCE

= 2.0mA, VCC= 5.0V

(MAX6806 only)

RESET Output Voltage
(MAX6806/MAX6808)

V

0.8V

CC

VCC= 5.5V, RESET deasserted
(MAX6808 only)

µAI

OH

RESET Output Leakage Current

MAX6806/MAX6807/MAX6808

Voltage Detectors

_______________________________________________________________________________________

3

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

0

10

5

20
15

30
25

35

45
40

50

-60 -30 0 30 60 12090

SUPPLY CURRENT vs. TEMPERATURE

MAX6806/7/8-01

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

VCC = 5.0V

VCC = 3.3V

VCC = 1.8V

VCC = 1.0V

25

29
27

33
31

35

37

43
41
39

45

-60 -30-15 0-45 15 30 45 7560 90105120135

POWER-DOWN RESET DELAY

vs. TEMPERATURE

MAX6806/7/8toc02

TEMPERATURE (°C)

RESET DELAY (µs)

VOD = V

TH-

- VCC = 100mV

V

CC

FALLING AT 1mV/µS

4

6
5

7

9
8

11
10

12

-60 -30 0 30 60 12090

POWER-UP RESET DELAY vs. TEMPERATURE

MAX6806/7/8-03

TEMPERATURE (°C)

DELAY TIME (µs)

VOD = V

CC

- VTH+

VOD = 50mV

VOD = 200mV

VOD = 100mV

0.9900

0.9940

0.9920

0.9980

0.9960

1.0020

1.0000

1.0040

1.0080

1.0060

1.0100

-40 -15 0-30 15 30 6045 8575

NORMALIZED RESET THRESHOLD

vs. TEMPERATURE

MAX6806/7/8-04

TEMPERATURE (°C)

NORMALIZED RESET THRESHOLD

V

CC

RISING (V

TH+

)

V

CC

FALLING (V

TH-

)

1

Active-Low Reset Output (MAX6806/MAX6808). RESET remains low
while V

CC

is below the reset-threshold voltage or while MR is held high.

Active-High Reset Output (MAX6807). RESET remains high while VCCis

below the reset-threshold voltage or while MR is held high.
2 Ground
3 Supply Voltage Input

— Active-High Manual Reset Input. Internal 80kΩ resistor to GND.

SOT23/SC70

FUNCTION

Pin Description

RESET

RESET

GND

V

CC

MR

NAME

1

4
3
2

SOT143

PIN

MAX6806/MAX6807/MAX6808

Voltage Detectors

4 _______________________________________________________________________________________

_______________Detailed Description

Reset Output

The MAX6806 voltage detector features an active-low,
push-pull RESET output, while the MAX6807 features
an active-high, push-pull RESET output. Unlike micro­processor (µP) supervisory circuits that offer a reset
timeout period, the MAX6806 and MAX6807 RESET
goes high and RESET goes low virtually immediately
once V

CC

exceeds the reset threshold. If a brownout

occurs (V

CC

falls below the reset threshold), RESET
goes low and RESET goes high. RESET is guaranteed
to be a logic low for V

CC

≥ 1V and RESET is guaran-

teed to be a logic high for V

CC

≥ 1.2V.

The MAX6808 features an active-low, open-drain RESET
output. The output sinks current when V

CC

falls below
the reset threshold. Connect a pull-up resistor from
RESET to any supply voltage up to 6V (Figure 1). Select
a resistor value large enough to provide a logic low and
small enough to provide a logic high while supplying all
input and leakage currents connected to the RESET
line. A 100kΩ resistor is sufficient in applications driving
high-impedance loads.

The manual reset input (MR, 4-pin SOT143 package)
can also initiate a reset (see

Manual Reset Input

sec-

tion).

Manual Reset Input

Many applications require manual-reset capabilities,
allowing an operator, a test technician, or external logic
circuitry to initiate a reset. A logic high on MR asserts a
reset and remains asserted while MR is high. This input
has an 80kΩ pull-down resistor, so the input may be left
unconnected if not used. Connect a normally open
momentary switch from MR to V

CC

to create a manual­reset function. If MR is driven from long cables or if the
device is used in a noisy environment, connecting a

0.1µF capacitor from MR to ground provides noise
immunity.

Hysteresis

The MAX6806/MAX6807/MAX6808 feature internal hys­teresis that creates two trip points: one for the rising
supply voltage and one for the falling supply voltage
(Figure 2). The hysteresis prevents the output from oscil­lating (chattering) when V

CC

is near the reset threshold.

Reset Threshold Accuracy

The MAX6806/MAX6807/MAX6808 are ideal for sys­tems using a 5V ±5%, 3V ±5%, or 2.5V ±5% power
supply with ICs specified for 5V ±10%, 3V ±10%, or

2.5V ±10%, respectively. The reset is guaranteed to
assert after the power supply falls out of regulation, but
before power drops below the minimum specified oper­ating voltage range for the system ICs.

MAX6808

V

CC

V

CC

GND

+3.3V

GND

+5.0V

100k

5V SYSTEM

RESET

Figure 1. The MAX6808 open-drain RESET output allows use
with multiple supplies.

V

TH+

HYST

RESET

(MAX6806/MAX6808)

RESET

(MAX6807)

V

HYST

= V

TH+

- V

TH-

V

OH

V

OL

V

OH

V

OL

V

TH-

Figure 2. Input and Output Waveforms with VCCVaried

Applications Information

Negative-Going VCCTransients

In addition to asserting a reset signal during power-up,
power-down, and brown-out conditions, the MAX6806/
MAX6807/MAX6808 are immune to short-duration, neg­ative-going VCCtransients.

Figure 3 displays typical transient durations vs. reset­comparator overdrive for which the MAX6806/MAX6807/
MAX6808 do not generate a reset pulse. The graph was
generated using a negative-going pulse applied to VCC,
starting 0.5V above the actual reset threshold and end­ing below it by the magnitude indicated (reset-compara­tor overdrive). The graph indicates the maximum pulse
width a negative-going VCCtransient can have without
causing a reset pulse. As the magnitude of the transient
increases (goes further below the reset threshold), the
maximum allowable pulse width decreases. A 0.1µF
capacitor mounted as close as possible to VCCpro­vides additional transient immunity.

Ensuring a Valid Reset Output Down to

V

CC

= Ground

When VCCfalls below 1V, the MAX6806/MAX6808
RESET output no longer sinks current—it becomes an
open circuit. Therefore, high-impedance CMOS logic
inputs connected to RESET can drift to undetermined
voltages. This presents no problem in most applica­tions, since most circuitry is inoperative when VCCis
below 1V. In applications where RESET must be valid
down to ground, add a pull-down resistor to RESET so
any stray leakage currents flow to ground, holding
RESET low (Figure 4). Select R1 to be large enough not
to load RESET and small enough to pull RESET to
ground. For most applications, 100kΩ will not load
RESET and will pull RESET to ground. Similarly, if
RESET (MAX6807) must be valid below 1.2V, add a
pull-up resistor to RESET.

MAX6806/MAX6807/MAX6808

Voltage Detectors

_______________________________________________________________________________________ 5

80

70

20

10 100 1000

40

30

50

60

RESET COMPARATOR OVERDRIVE, V

TH-

- V

CC

(mV)

MAXIMUM TRANSIENT DURATION (µs)

TA = +25°C

MAX680 46

Figure 3. Maximum Transient Duration without Causing a
Reset Pulse vs. Reset Comparator Overdrive

MAX6806

MAX6807

V

CC

V

CC

GND

GND

RESET

RESET

R1
100k

R1
100k

Figure 4. RESET / RESET Valid to VCC= Ground Circuit

MAX6806/MAX6807/MAX6808

Interfacing to µPs with

Bidirectional Reset Pins

µPs with bidirectional reset pins (such as the Motorola
68HC11 series) can contend with push-pull RESET out­puts, resulting in indeterminate logic levels. Use the
MAX6808 with the open-drain RESET when interfacing
to this type of controller.

Voltage Detectors

6 _______________________________________________________________________________________

MAX6808

V

CC

V

CC

V

CC

GND GND

4.7k
µP

RESET RESET

Figure 5. Interfacing to µPs with Bidirectional Reset I/O

Selector Guide (continued)

PART*

MAX6806XR46-T

RESET OUTPUT TOP MARK

AAA

NOMINAL

V

TH-

(V)

†

4.6
MAX6806XR26-T
MAX6806XR23-T

AAB
AAC

2.6

2.3

†

Other reset thresholds may be available. Contact factory for availability.

MAX6807XR46-T AAD 4.6

MAX6808UR26-T
MAX6808US46-T

FZDV

KABY

2.6

4.6
MAX6808US26-T KABZ 2.6

MAX6807UR46-T

FZDS 4.6
MAX6807UR26-T
MAX6807US46-T

FZDT

KABW

2.6

4.6

MAX6807US26-T KABX 2.6

MAX6807XR26-T AAE 2.6
MAX6808UR46-T

FZDU 4.6

MAX6808XR46-T AAF 4.6
MAX6808XR26-T AAG 2.6

Active-Low, Push-Pull

Active-High, Push-Pull

Active-Low, Open-Drain

___________________Chip Information

TRANSISTOR COUNT: 72

MAX6806/MAX6807/MAX6808

Voltage Detectors

_______________________________________________________________________________________ 7

Pin Configurations

Typical Operating Circuit

GND

1

3 V

CC

(RESET)/RESET

MAX6806
MAX6807
MAX6808

SOT23/SC70

TOP VIEW

2

1

2

4

3

GND

V

CC

MR

( ) ARE FOR MAX6807

(RESET)/RESET

MAX6806
MAX6807
MAX6808

SOT143

V

CC

V

CC

V

CC

MAX6806
MAX6807

µP

MAX6808

(RESET)/RESET

GND GND

( ) ARE FOR MAX6807

RESET
INPUT

MAX6806/MAX6807/MAX6808

Voltage Detectors

8 _______________________________________________________________________________________

Package Information

SC70, 3L.EPS

MAX6806/MAX6807/MAX6808

Voltage Detectors

_______________________________________________________________________________________ 9

Package Information (continued)

SOTPO3L.EPS

MAX6806/MAX6807/MAX6808

Voltage Detectors

10 ______________________________________________________________________________________

Package Information (continued)

SOT1434.EPS

MAX6806/MAX6807/MAX6808

Voltage Detectors

______________________________________________________________________________________ 11

NOTES

MAX6806/MAX6807/MAX6808

Voltage Detectors

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

12

____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

12

____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

NOTES