19-1756; Rev 3; 12/05
Quad Voltage µP Supervisory Circuit
in SOT Package
General Description
The MAX6339 is a precision quad voltage monitor with
microprocessor (µP) supervisory reset timing. The device
can monitor up to four system supply voltages without
any external components and asserts a single reset if any
supply voltage drops below its preset threshold. The
device significantly reduces system size and component
count while improving reliability compared to separate
ICs or discrete components.
A variety of factory-trimmed threshold voltages are avail-
able to accommodate different supply voltages and toler-
ances with minimal external component requirements.
The selection includes internally fixed options for monitor-
ing +5.0V, +3.3V, +3.0V, +2.5V, +1.8V, and -5.0V sup-
plies with -5% and/or -10% tolerances. The device is also
available with one or two user-adjustable threshold
options if non-standard thresholds are desired (use exter-
nal resistor-divider network).
The quad monitor provides a single active-low reset out-
put that is asserted when any monitored input is below its
associated threshold. The output is open drain with a
weak internal pullup (10µA) to IN2. Reset remains low for
a reset timeout period (140ms min) after all voltages are
above the selected thresholds. The output is valid as long
as either the IN1 or IN2 input voltage remains > 1V.
The MAX6339 is available in a small 6-pin SOT23 pack-
age and operates over the extended (-40°C to +85°C)
temperature range.
Features
♦
Monitors Four Power-Supply Voltages
♦
Precision Factory-Set Reset Threshold Options
for +5.0V, +3.3V, +3.0, +2.5V, +1.8V, and -5.0V
Supplies
♦
User-Adjustable Voltage Monitoring Threshold
Options
♦
Low 55µA Supply Current
♦
Open-Drain
RESET
Output with 10µA Internal
Pullup
♦
140ms (min) Reset Timeout Period
♦
RESET
Valid to IN1 = 1V or IN2 = 1V
♦
Immune to Short Monitored Supply Transients
♦
No External Components Required
♦
Guaranteed from -40°C to +85°C
♦
Small 6-Pin SOT23 Package
MAX6339
Ordering Information
PART
MAX6339_UT-T*
TEMP. RANGE
-40°C TO +85°C
PIN-PACKAGE
6 SOT23-6
________________________Applications
Telecommunications
High-End Printers
Desktop and Network Computers
Data Storage Equipment
Networking Equipment
Industrial Equipment
Set-Top Boxes
*Insert
the desired letter from the Selector Guide into the blank
to complete the part number. There is a 2500 piece minimum
order increment requirement on the SOT package and these
devices are available in tape-and-reel only.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Typical Operating Circuit
IN1
SUPPLIES
TO BE
MONITORED
IN2
IN3
IN4
MAX6339
µP
RESET
GND
Pin Configuration appears at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Quad Voltage µP Supervisory Circuit
in SOT Package
MAX6339
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND)
Input Voltages (IN_ ) (except -5V)............................-0.3V to +6V
RESET.......................................................................-0.3V
to +6V
Input Voltage (-5V Input) ..........................................-6V to +0.3V
Continuous
RESET
Current .................................................20mA
Continuous Power Dissipation (T
A
= +70°C)
6-pin SOT23 (derate 8.7mW/°C above +70°C).........695.7mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
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.
ELECTRICAL CHARACTERISTICS
(V
IN2
= +1V to +5.5V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
IN2
= +3.0V to +3.3V, T
A
= +25°C, unless
otherwise noted.) (Note 1)
PARAMETER
Supply Voltage Range
(Notes 2, 3)
SYMBOL
V
IN2
V
IN
_ = input threshold voltage (input threshold
voltage of 1.8V, 2.5V, 5V)
V
IN2
= input threshold voltage (input threshold
voltage of 3.0V, 3.3V) (Note 4)
I
IN
_
V
IN
_ = 0 to V
IN2
(input threshold voltage = +1.23V)
V
IN1
= 1.5V (MAX6339 K/L only)
V
IN
_ = -5V (input threshold voltage = -5V)
+5V (-5%) threshold
+5V (-10%) threshold
+3.3V (-5%) threshold
Reset
Threshold Voltage
V
IN
_
decreasing
V
TH
+3.3V (-10%) threshold
+3.0V (-5%) threshold
+3.0V (-10%) threshold
+2.5V (-10% ) threshold
+1.8V (-10%) threshold
V
IN
_
increasing
Adjustable Threshold
Threshold Voltage
Temperature Coefficient
Threshold Hysteresis
Reset Delay
Reset Active Timeout
Period
V
HYST
t
RD
t
RP
V
IN
= V
TH
to (V
TH
- 50mV) (all inputs except –5V)
or V
IN
_ = V
TH
to (V
TH
+ 50mV) (-5V input only)
140
V
TH
V
IN
decreasing
-5V (+5%) threshold
-5V (+10%) threshold
4.50
4.25
3.00
2.85
2.70
2.55
2.13
1.53
-4.75
-4.50
1.20
-0.1
0.4
-15
4.63
4.38
3.08
2.93
2.78
2.63
2.19
1.58
-4.63
-4.38
1.23
60
0.3
20
200
280
CONDITIONS
MIN
1.0
25
55
TYP
MAX
5.5
40
115
µA
+0.1
1.5
-20
4.75
4.50
3.15
3.00
2.85
2.70
2.25
1.62
-4.50
-4.25
1.26
V
ppm/°C
%
µs
ms
V
UNITS
V
Input Current
2
_______________________________________________________________________________________
Quad Voltage µP Supervisory Circuit
in SOT Package
ELECTRICAL CHARACTERISTICS (continued)
(V
IN2
= +1V to +5.5V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
IN2
= +3.0V to +3.3V, T
A
= +25°C, unless
otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
V
IN2
= 5V, I
SINK
= 2mA
Output Low Voltage
V
OL
V
IN2
= 2.5V, I
SINK
= 1.2mA
V
IN1
= V
IN2
= 1V, I
SINK
= 50µA
Output High Voltage
Output High Source
Current
V
OH
I
OH
V
IN2
> 2.55V, I
SOURCE
= 6µA
(RESET unasserted)
V
IN2
> 2.55V (RESET unasserted)
0.8
✕
V
IN2
6
10
MIN
TYP
MAX
0.4
0.4
0.4
V
µA
V
UNITS
MAX6339
Note 1:
Note 2:
Note 3:
Note 4:
100% production tested at T
A
= +25°C. Limits over temperature guaranteed by design.
The device is powered from input IN2.
The
RESET
output is guaranteed to be in the correct state for IN1 or IN2 down to 1V.
Monitored voltage (+3.3V, +3.0V) is also the device power supply. Supply current splits as follows: 25µA for the resistor-
divider (for the monitored voltage) and 30µA for other circuits.
Typical Operating Characteristics
(V
IN2
= +3.0V, T
A
= +25°C)
I
IN2
INPUT CURRENT
vs. I
IN2
VOLTAGE
MAX6339toc02
I
IN2
INPUT CURRENT vs. TEMPERATURE
80
I
IN2
INPUT CURRENT (µA)
75
70
65
60
55
50
45
40
35
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
V
IN2
= +3.0V
V
IN2
= +3.3V
MAX6339toc01
NORMALIZED THRESHOLD ERROR
vs. TEMPERATURE
NORMALIZED THRESHOLD ERROR (%)
0.10
0.05
0
-0.5
-0.10
-0.15
-0.20
-0.25
V
IN2
= +3.0V
-0.30
-40
-20
0
20
40
60
80
V
TH
= 1.8V
V
TH
= +5V
MAX6339toc03
85
85
80
I
IN2
INPUT CURRENT (
µA)
75
70
65
60
55
50
3.0
3.5
4.0
4.5
5.0
0.15
5.5
INPUT VOLTAGE (V)
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Quad Voltage µP Supervisory Circuit
in SOT Package
MAX6339
Typical Operating Characteristics (continued)
(V
IN2
= +3.0V, T
A
= +25°C)
MAXIMUM IN_ TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX6339toc04
RESET DELAY vs. RESET THRESHOLD
OVERDRIVE (IN_ decreasing)
70
60
RESET DELAY (µs)
50
40
30
20
10
0
RESET
2V/div
MAX6339toc05
RESET PULLUP AND PULLDOWN
RESPONSE (C
L
= 47pF)
MAX6339toc06
80
MAXIMUM IN_ TRANSIENT DURATION (µs)
70
60
50
40
30
20
10
0
RESET ASSERTED
ABOVE THIS LINE
80
IN_
100mV/div
0 100 200 300 400 500 600 700 800 900 1000
RESET THRESHOLD OVERDRIVE (mV)
0 100 200 300 400 500 600 700 800 900 1000
RESET THRESHOLD OVERDRIVE (mV)
10µs/div
RESET TIMEOUT DELAY
vs. TEMPERATURE
MAX6339toc07
RESET TIMEOUT DELAY
MAX6339toc08
215
210
RESET TIMEOUT DELAY (ms)
205
200
195
190
185
180
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
IN_
2V/div
2V/div
RESET
2V/div
200ms/div
Pin Description
PIN
1
2
3
4
5
6
NAME
IN1
IN2
IN3
IN4
GND
RESET
FUNCTION
Input Voltage 1. See the
Selector Guide
for monitored voltages.
Input Voltage 2. See the
Selector Guide
for monitored voltages. IN2 is the power-supply input for
the device.
Input Voltage 3. See the
Selector Guide
for monitored voltages.
Input Voltage 4. See the
Selector Guide
for monitored voltages.
Ground
Reset Output, Active Low.
RESET
goes low when any input goes below its specified threshold. After
all inputs are above their threshold voltage,
RESET
remains low for at least 140ms (minimum) before
going high.
RESET
output is open drain with a weak internal pullup to IN2.
4
_______________________________________________________________________________________
Quad Voltage µP Supervisory Circuit
in SOT Package
Detailed Description
The MAX6339 is a very small, low-power, quad voltage
µP supervisory circuit designed to maintain system
integrity in multi-supply systems (Figure 1). The device
offers several internally trimmed undervoltage threshold
options that minimize or eliminate the need for external
components. Preset voltage monitoring options for
+5.0V, +3.3V, +3.0V, +2.5V, +1.8V, and -5.0V make it
ideal for telecommunications, desktop and notebook
computers, high-end printers, data storage equipment,
and networking equipment applications.
The quad monitor/reset includes an accurate bandgap
reference, four precision comparators, and a series of
internal trimmed resistor-divider networks to set the fac-
tory-fixed reset threshold options. The resistor networks
scale the specified IN_ reset voltages to match the
internal bandgap reference/comparator voltage. User-
adjustable threshold options bypass the internal resis-
tor networks and connect directly to one of the
comparator inputs (an external resistor-divider network
is required for threshold matching). All threshold volt-
age options, fixed and adjustable, are indicated
through a single-letter code in the product number (see
the
Selector Guide).
Each of the internal comparators has a typical hystere-
sis of 0.3% with respect to its reset threshold. This built-
in hysteresis improves the monitor’s immunity to
ambient noise without significantly reducing threshold
accuracy when an input sits at its specified reset volt-
age. The MAX6339 is also designed to ignore short IN_
transients. See the
Typical Operating Characteristics
for
a glitch immunity graph.
threshold, the reset output is asserted and guaranteed
to remain low while either IN1 or IN2 is above +1.0V.
MAX6339
User-Adjustable Thresholds
The MAX6339 offers several monitor options with user-
adjustable reset thresholds. The threshold voltage at
each adjustable IN_ input is typically 1.23V. To monitor
a voltage > 1.23V, connect a resistor-divider network to
the circuit as shown in Figure 4.
V
INTH
= 1.23V x (R1 + R2) / R2
or, solved in terms of R1:
R1 = R2 ((VI
NTH
/ 1.23V) - 1)
Because the MAX6339 has a guaranteed input current
of ±0.1µA on its adjustable inputs, resistor values up to
100kΩ can be used for R2 with < 1% error.
Unused Inputs
If some monitor inputs are to be unused, they must be
tied to a supply voltage greater in magnitude than their
specified threshold voltages. For unused IN3 or IN4
options with positive thresholds (fixed or adjustable),
the inputs can be connected directly to the IN2 supply.
For unused IN4 options with negative thresholds, the
input must be tied to a more negative supply. The IN2
input must always be used for normal operation (device
power-supply pin). Unused pins cannot be connected
to ground or allowed to float.
Applications Information
Reset Output
The MAX6339
RESET
output is asserted low when any
of the monitored IN_ voltages drop below its specified
reset threshold (or above for -5V option) and remain
low for the reset timeout period (140ms minimum) after
all inputs exceed their thresholds (Figure 2). The output
is open drain with a weak internal pullup to the moni-
tored IN2 supply (10µA typ). For many applications no
external pullup resistor is required to interface with
other logic devices. An external pullup resistor to any
voltage from 0 to +5.5V can overdrive the internal
pullup if interfacing to different logic supply voltages
(Figure 3). Internal circuitry prevents reverse current
flow from the external pullup voltage to IN2.
The MAX6339 is normally powered from the monitored
IN2 supply when all input voltages are above their
specified thresholds. When any supply drops below its
Negative Voltage Monitoring Beyond -5V
The MAX6339 is offered with options to monitor -5V sup-
plies with internally fixed thresholds. To monitor supplies
more negative than -5V, a low-impedance resistor-
divider network can be used external to the MAX6339 as
shown in Figure 5. The current through the external resis-
tor-divider should be greater than the input current for
the -5V monitor options. For an input monitor current
error of < 1%, the resistor-divider current should
≥
2mA
(for I
IN4
= 20µA max). Set R2 = 2.5kΩ. Calculate R1
based on the desired V
IN_
reset threshold voltage, using
the following formula:
R1 = R2
✕
[(V
INTH
/ V
TH
) -1]
where R2
≤
2.49kΩ, V
INTH
= desired threshold voltage
and V
TH
is the internal threshold voltage.
_______________________________________________________________________________________
5
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