MAX6459UTC-T [MAXIM]
High-Voltage, Low-Current Voltage Monitors in SOT Packages; 高电压,低电流电压监测器,SOT封装型号: | MAX6459UTC-T |
厂家: | MAXIM INTEGRATED PRODUCTS |
描述: | High-Voltage, Low-Current Voltage Monitors in SOT Packages |
文件: | 总15页 (文件大小:219K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
General Description
Features
o Wide Supply Voltage Range, 4V to 28V
o Internal 2.25V 2.5ꢀ Reference
o Low Current (3.5µA, typ at 12V)
The MAX6457–MAX6460 high supply voltage, low-power
voltage monitors operate over a 4V to 28V supply voltage
range. Each device includes a precision bandgap refer-
ence, one or two low-offset voltage comparators, internal
threshold hysteresis, power-good or reset timeout
options, and one or two high-voltage open-drain outputs.
Two external resistors (three for window detection) set the
trip threshold voltages.
o Open-Drain n-Channel Output (28V Compliant)
o Internal Threshold Hysteresis Options
(0.5ꢀ, 5ꢀ, 8.3ꢀ)
o Two IN-to-OUT Timeout Period Options
(50µs, 150ms)
The MAX6457 is a single voltage monitor for undervoltage
or overvoltage detection. A logic-based clear input either
latches the output for overvoltage applications or allows
the device to operate in transparent mode. The MAX6458
includes two comparators (one overvoltage and one
undervoltage) for window detection and a single output to
indicate if the monitored input is within an adjustable volt-
age window. The MAX6459 includes dual overvoltage/
undervoltage comparators with two independent com-
parator outputs. Use the MAX6459 as a window com-
parator with separate undervoltage and overvoltage
outputs or as two independent, single voltage monitors.
The MAX6460 includes a single comparator and an inter-
nal reference, and can also accept an external reference.
The inverting and noninverting inputs of the comparator
are externally accessible to support positive or negative
voltage monitors and to configure the device for active-
high or active-low output logic.
The MAX6457/MAX6458 offer fixed timing options as a
voltage detector with a 50µs typical delay or as a reset cir-
cuit with a 90ms minimum reset timeout delay. The moni-
tored input must be above the adjusted trip threshold (or
within the adjusted voltage window for the MAX6458) for
the selected timeout period before the output changes
state. The MAX6459/MAX6460 offer only a fixed 50µs
timeout period. Internal threshold hysteresis options (0.5%,
5%, and 8.3% for the MAX6457/MAX6458/MAX6459, and
0.5% for the MAX6460) reduce output chatter in noise-
sensitive applications. Each device is available in a small
SOT23 package and specified over the extended temper-
ature range of -40°C to +125°C.
o Internal Undervoltage Lockout
o Immune to Short Voltage Transients
o Small SOT23 Packages
o Few External Components
o Fully Specified from -40°C to +125°C
Ordering Information
PART
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
5 SOT23
MAX6457UKD_ _-T
MAX6458UKD_ _-T
MAX6459UT_-T
MAX6459UT_/V+
MAX6460UT-T
5 SOT23
6 SOT23
5 SOT23
6 SOT23
Note: The MAX6457/MAX6458/MAX6459 are available with
factory-trimmed internal hysteresis options. The MAX6457 and
MAX6458 offer two fixed timing options. Select the desired hys-
teresis and timing options using Table 1 or the Selector Guide at
the end of the data sheet, and enter the corresponding letters
and numbers in the part number by replacing “_ _” or “_”. These
devices are offered in tape-and-reel only and must be ordered in
2500-piece increments.
Devices are available in both leaded and lead(Pb)-free/RoHS-
compliant packaging. Specify lead(Pb)-free by replacing “-T”
with “+T” when ordering.
/V denotes an automotive qualified part.
Pin Configurations appear at end of data sheet.
Typical Operating Circuit
Applications
Undervoltage Monitoring/Shutdown
Overvoltage Monitoring/Protection
Window Voltage Detection Circuitry
Multicell Battery-Stack Powered Equipment
Notebooks, eBooks
+21V (NOMINAL)
IN
OUT
BATTERY
CHARGER
DC-DC
CONVERTER
SHDN
V
CC
MAX6457
R1
R2
R
PULLUP
LOAD
5-CELL
Li+
BATTERY
STACK
Automotive
IN+
OUT
Industrial
Telecom
GND
CLEAR
Networking
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-2048; Rev 6; 12/12
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
ABSOLUTE MAXIMUM RATINGS
Junction Temperature......................................................+150°C
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow)
V , OUT, OUTA, OUTB, CLEAR to GND ..........-0.3V to +30.0V
CC
IN+, IN- to GND..........................................-0.3V to (V
REF to GND..............-0.3V to the lower of +6V and (V
+ 0.3V)
+ 0.3V)
CC
CC
Input Currents (V , IN+, IN-) ............................................20mA
CC
Sink Current (OUT, OUTA, OUTB)......................................20mA
Lead(Pb)-free................................................................+260°C
Containing lead (Pb).....................................................+240°C
Continuous Power Dissipation (T = +70°C)
5-Pin SOT23 (derate 7.1 mW/°C above +70°C)............571mW
6-Pin SOT23 (derate 8.7 mW/°C above +70°C)............696mW
A
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
= 4V to 28V, T = -40°C to +125°C, unless otherwise specified. Typical values are at T = +25°C.) (Note 1)
CC
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
28
UNITS
Operating Voltage Range
V
(Note 2)
4
V
CC
V
V
V
= 5V, no load
2
5
CC
CC
CC
Supply Current
I
= 12V, no load
= 24V, no load
3.5
7.5
µA
CC
6.5
12.5
1.255
1.255
1.255
1.255
1.194
1.194
1.151
1.151
T
A
T
A
= -40°C to +85°C, V ≥ 4V
1.195
1.170
1.180
1.228
CC
V
rising
IN
V
TH+
= +85°C to +125°C, V
≥ 4V
CC
T
A
T
A
T
A
T
A
T
A
T
A
= -40°C to +85°C
MAX645_U_D_A
MAX645_U_D_B
MAX645_U_D_C
= +85°C to +125°C 1.155
= -40°C to +85°C 1.133
= +85°C to +125°C 1.111
= -40°C to +85°C 1.093
Threshold Voltage
V
V
IN
V
TH-
falling
= +85°C to +125°C 1.071
MAX64_ _U_D_A
MAX64_ _U_D_B
MAX64_ _U_D_C
(Note 2)
0.5
5
Threshold Voltage Hysteresis
%V
TH+
8.3
IN Operating Voltage Range
IN Leakage Current
V
0
V
V
IN
CC
I
V
= 1.25V, V
= +28V
-55
+55
nA
IN
IN
CC
MAX645_UKD0_
MAX6459UT_
MAX6460UT
50
µs
OUT Timeout Period
t
TP
MAX6457 and MAX6458 only,
D3 option
90
150
2
210
0.4
ms
ms
V
V
rising from GND to V
≥ 4V in less than
CC
CC
Startup Time
1µs (Note 3)
V
IL
CLEAR Input Logic Voltage
(MAX6457)
V
2
IH
2
Maxim Integrated
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
ELECTRICAL CHARACTERISTICS (continued)
(V
= 4V to 28V, T = -40°C to +125°C, unless otherwise specified. Typical values are at T = +25°C.) (Note 1)
CC
A
A
PARAMETER
SYMBOL
CONDITIONS
= 250µA, OUT asserted,
MIN
TYP
MAX
UNITS
V
≥ 1.5V, I
SINK
CC
0.4
T
A
= -40°C to +85°C
Output Voltage Low
V
V
OL
V
≥ 4.0V, I
= 1mA, OUT asserted,
CC
SINK
0.4
T
A
= -40°C to +125°C
Output Leakage Current
Output Short-Circuit Sink
I
V
= 5V, V = 28V (Note 4)
OUT
500
nA
LKG
CC
I
OUT asserted, OUT = V
10
mA
SC
CC
MAX6460
Reference Short-Circuit Current
REF = GND
7
mA
V
T
T
= -40°C to +85°C
2.183
2.171
2.25
2.25
2.303
2.303
A
Reference Output Voltage
Load Regulation
V
REF
= +85°C to +125°C
A
Sourcing: 0 ≤ I
sinking: 0 ≤ |I
≤ 100µA,
| ≤ 300nA
REF
50
µV/µA
REF
Input Offset Voltage
V
-4.5
-25
0
+4.5
+25
1.4
mV
mV
nA
pA
V
OFFSET
Input Hysteresis
6
2
Input Bias Current
I
V
V
+ = 1.4V, V - = 1V
IN
BIAS
IN
Input Offset Current
I
OFFSET
CMVR
CMRR
Common-Mode Voltage Range
Common-Mode Rejection Ratio
80
80
dB
Comparator Power-Supply
Rejection Ratio
PSRR
+ = V - = 1.4V
dB
IN
IN
Note 1: Devices are production tested at T = +25°C. Overtemperature limits are guaranteed by design.
A
Note 2: IN voltage monitoring requires that V
≥ 4V, but OUT remains asserted in the correct undervoltage lockout state for V
CC
CC
down to 1.5V.
Note 3: Startup time is the time required for the internal regulator and reference to reach specified accuracy after the monitor is
powered up from GND.
Note 4: The open-drain output can be pulled up to a voltage greater than V
but cannot exceed +28V.
CC
Maxim Integrated
3
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Typical Operating Characteristics
(GND = 0, R
= 10kΩ, and T = +25°C, unless otherwise noted.)
A
PULLUP
TRIP THRESHOLD VOLTAGE
vs. TEMPERATURE (0.5% HYSTERESIS)
TRIP THRESHOLD VOLTAGE
vs. TEMPERATURE (5% HYSTERESIS)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
1.25
1.23
1.21
1.19
1.17
1.15
1.13
1.11
1.25
1.23
1.21
1.19
1.17
1.15
1.13
1.11
12
10
8
V
+ (RISING)
TH
V
TH
V
TH
+ (RISING)
T
= +125°C
A
V
- (FALLING)
TH
T
= +25°C
A
6
4
- (FALLING)
T
= -40°C
A
2
0
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
4
10
16
(V)
22
28
TEMPERATURE (°C)
TEMPERATURE (°C)
V
CC
TRIP THRESHOLD VOLTAGE
vs. TEMPERATURE (8.3% HYSTERESIS)
OUTPUT LOW VOLTAGE
vs. OUTPUT SINK CURRENT
1.25
1.23
1.21
1.19
1.17
1.15
1.13
1.11
100,000
10,000
1000
100
T
= +125°C
A
V
+ (RISING)
TH
T
= +25°C
A
T
= -40°C
A
10
V
- (FALLING)
TH
1
V
= 12V
CC
0.1
-40 -25 -10
5
20 35 50 65 80 95 110 125
0.01
0.1
1
10
100
TEMPERATURE (°C)
I
(mA)
SINK
4
Maxim Integrated
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Typical Operating Characteristics (continued)
(GND = 0, R
= 10kΩ, and T = +25°C, unless otherwise noted.)
A
PULLUP
OUTPUT SHORT-CIRCUIT SINK CURRENT
vs. TEMPERATURE
OUTPUT FALL TIME
vs. SUPPLY VOLTAGE
TIMEOUT PERIOD vs. TEMPERATURE
15
14
13
12
11
10
9
1000
100
10
2000
1800
1600
1400
1200
1000
800
V
= 12V
CC
T
= +125°C
A
MAX6457UKD3
MAX6457UKD0
V
= 5V
CC
1
600
T
= +25°C
A
V
= 24V
CC
0.1
0.01
400
T
= -40°C
200
A
0
8
-40 -25 -10
5
20 35 50 65 80 95 110 125
4
8
12
16
(V)
20
24
28
-40 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (C)
TEMPERATURE (°C)
V
CC
MAXIMUM TRANSIENT DURATION
vs. INPUT OVERDRIVE
INPUT LEAKAGE CURRENT
vs. TEMPERATURE
300
250
200
150
100
50
10
8
V
= 1.25V
IN
6
4
2
OUT ASSERTED LOW
ABOVE THIS LINE
0
0
-2
1
10
100
1000
-40 -25 -10
5
20 35 50 65 80 95 110 125
INPUT OVERDRIVE (V - V +) (mV)
TEMPERATURE (°C)
TH-
IN
Maxim Integrated
5
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Pin Description
PIN
NAME
FUNCTION
MAX6457 MAX6458 MAX6459 MAX6460
MAX6457: Open-Drain Monitor Output. OUT requires an external pullup
resistor. OUT asserts low for V
between 1.5V and 4V. OUT asserts low
CC
when V
when V
drops below V
and goes high after the timeout period (t
)
TP
IN+
IN+
TH-
.
exceeds V
TH+
MAX6458: Open-Drain Monitor Output. OUT requires an external pullup
resistor. OUT asserts low for V between 1.5V and 4V. OUT asserts low
CC
1
1
—
1
OUT
when V
drops below V
or when V exceeds V
. OUT goes
TH+
IN+
TH-
IN-
high after the timeout period (t ) when V
exceeds V
and V
TH+ IN-
TP
IN+
drops below V
.
TH-
MAX6460: Open-Drain Monitor Output. OUT requires an external pullup
resistor. OUT asserts low for V between 1.5V and 4V. OUT asserts low
CC
when V
drops below V . OUT goes high when V
is above V
.
IN+
IN-
IN+
IN-
Open-Drain Monitor A Undervoltage Output. OUTA requires an external
pullup resistor. OUTA goes low when V
drops below V
and goes
between
IN+
TH-
CC
—
—
—
—
1
5
—
—
OUTA
OUTB
high when V
exceeds V
. OUTA also goes low for V
TH+
IN+
1.5V and 4V.
Open-Drain Monitor B Overvoltage Output. OUTB requires an external
pullup resistor. OUTB goes low when V exceeds V and goes high
IN-
TH+
when V drops below V . OUTB also goes low when V drops
CC
IN-
TH-
below 4V.
2
3
2
3
2
3
2
3
GND
IN+
Ground
Adjustable Undervoltage Monitor Threshold Input. Noninverting input for
MAX6460.
Adjustable Overvoltage Monitor Threshold Input. Inverting input for
MAX6460.
—
4
4
4
4
IN-
Clear Input. For V
> V
, drive CLEAR high to latch OUT high.
TH+
IN+
Connect CLEAR to GND to make the latch transparent. CLEAR must be
low when powering up the device. Connect CLEAR to GND when not
used.
—
—
—
CLEAR
Reference. Internal 2.25V reference output. Connect REF to IN+ through
a voltage divider for active-low output. Connect REF to IN- through a
voltage divider for active-high output. REF can source up to 100µA and
sink up to 300nA. Leave REF floating when not used. REF output is
stable with capacitive loads from 0 to 50pF or greater than 1µF.
—
5
—
5
—
6
5
6
REF
V
Supply Voltage
CC
6
Maxim Integrated
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Functional Diagrams
V
CC
V
CC
IN+
IN-
MAX6458
UV
OV
MAX6457
TIMEOUT
OPTION
IN+
OUT
TIMEOUT
OPTION
LATCH
OUT
HYSTERESIS
OPTION
HYSTERESIS
OPTION
1.228V
CLEAR
1.228V
"UV": UNDERVOLTAGE
"OV": OVERVOLTAGE
GND
GND
Figure 2. MAX6458 Functional Diagram
Figure 1. MAX6457 Functional Diagram
V
CC
V
CC
IN+
IN-
MAX6459
OUTA
UV
OV
IN+
OUT
IN-
OUTB
REF
MAX6460
HYSTERESIS
OPTION
2.25V
1.228V
"UV": UNDERVOLTAGE
"OV": OVERVOLTAGE
GND
GND
Figure 3. MAX6459 Functional Diagram
Figure 4. MAX6460 Functional Diagram
Maxim Integrated
7
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Detailed Description
⎛
⎞
R4
R3+R4
Each of the MAX6457–MAX6460 high-voltage (4V to
28V), low-power voltage monitors include a precision
bandgap reference, one or two low-offset-voltage com-
parators, internal threshold hysteresis, internal timeout
period, and one or two high-voltage open-drain outputs.
V
= V
REF
REFD
⎜
⎟
⎝
⎠
⎛
⎞
V
TRIP
R1=R2
−1
⎜
⎟
V
⎝
⎠
REFD
Programming the Trip Voltage (V
)
TRIP
Two external resistors set the trip voltage, V
(Figure 5).
TRIP
where V
REFD
= reference output voltage (2.25V, typ),
= divided reference, V
REF
V
V
is the point at which the applied voltage (typically
) toggles OUT. The MAX6457/MAX6458/MAX6459/
TRIP
CC
V
= desired trip thresh-
TRIP
old in (in volts).
MAX6460’s high input impedance allows large-value
resistors without compromising trip-voltage accuracy.
To minimize current consumption, select a value for R2
between 10kΩ and 1MΩ, then calculate R1 as follows:
For an active-low power-good output, connect the
resistor divider R1 and R2 to the inverting input and the
reference-divider network to the noninverting input.
Alternatively, connect an external reference less than
1.4V to either input.
⎛
⎞
V
V
TRIP
R1=R2
- 1
⎜
⎟
⎝
⎠
TH
V
TRIP
V
CC
V
CC
R
PULLUP
R1
R2
V
CC
R
PULLUP
R1
R2
MAX6457–
MAX6460
IN+
OUT
(OUTA)
REF
IN+
OUT
(OUTA FOR
MAX6459)
OUT
OUT
MAX6460
GND
R3
REFD
R4
V
IN-
GND
R1 + R2
V
TRIP
= V
TH
R2
Figure 5a. Programming the Trip Voltage
Figure 5b. Programming the MAX6460 Trip Voltage
where V
= desired trip voltage (in volts), V
=
TH
TRIP
threshold trip voltage (V + for overvoltage detection
TH
V
HYST
or V - for undervoltage detection).
TH
V
TH+
Use the MAX6460 voltage reference (REF) to set the
trip threshold by connecting IN+ or IN- through a volt-
age divider (within the inputs common-mode voltage
range) to REF. Do not connect REF directly to IN+ or
IN- since this violates the input common-mode voltage
range. Small leakage currents into the comparators
inputs allows use of large value resistors to prevent
loading the reference and affecting its accuracy. Figure
5b shows an active-high power-good output. Use the
following equation to determine the resistor values
when connecting REF to IN-:
V
IN+
V
TH-
V
CC
V
OUT
t
t
TP
TP
0
Figure 6. Input and Output Waveforms (Noninverting Input Varied)
Maxim Integrated
8
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
>V
TH+
IN+
<V
TH-
V
CC
0
CLEAR
V
CC
OUT
t
TP
t
t
TP
TP
0
Figure 7. Timing Diagram (MAX6457)
Hysteresis
+21V
IN
OUT
Hysteresis adds noise immunity to the voltage monitors
and prevents oscillation due to repeated triggering
BATTERY
CHARGER
DC-DC
CONVERTER
SHDN
when V is near the threshold trip voltage. The hystere-
IN
V
CC
sis in a comparator creates two trip points: one for the
rising input voltage (V +) and one for the falling input
TH
voltage (V -). These thresholds are shown in Figure 6.
TH
MAX6457–
MAX6460
R1
R2
R
PULLUP
LOAD
5-CELL
Li+
BATTERY
STACK
The internal hysteresis options of the MAX6457/
MAX6458/MAX6459 are designed to eliminate the need
for adding an external hysteresis circuit.
IN+
OUT
(OUTA FOR
MAX6459)
GND
Timeout Period
The timeout period (t ) for the MAX6457 is the time
TP
from when the input (IN+) crosses the rising input
threshold (V +) to when the output goes high (see
TH
Figure 8. Undervoltage Lockout Typical Application Circuit
Figures 6 and 7). For the MAX6458, the monitored volt-
age must be in the “window” before the timeout starts.
The MAX6459 and MAX6460 do not offer the extended
timeout option (150ms). The extended timeout period is
suitable for overvoltage protection applications requir-
ing transient immunity to avoid false output assertion
due to noise spikes.
4V, OUT remains low regardless of the state of CLEAR.
Drive CLEAR high to latch OUT high when V + exceeds
IN
V
IN
+. When CLEAR is high, OUT does not deassert if
V + drops back below V -. Toggle CLEAR to deassert
TH
IN
OUT. Drive CLEAR low to make the latch transparent
(Figure 7). CLEAR must be low when powering up the
MAX6457. To initiate self-clear at power-up, add a 100kΩ
Latched-Output Operation
pullup resistor from CLEAR to V
and a 1µF capacitor
CC
The MAX6457 features a digital latch input (CLEAR) to
from CLEAR to GND to hold CLEAR low. Connect
CLEAR to GND when not used. See Figure 9.
latch any overvoltage event. If the voltage on IN+ (V +)
IN
is below the internal threshold (V -), or if V
TH
is below
CC
Maxim Integrated
9
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
FUSE
V
SUPPLY
V
SUPPLY
R1
R2
V
CC
V
LOAD
CC
IN+
R3
MAX6457–
MAX6460
MAX6457–
MAX6460
100kΩ
R
PULLUP
LOAD
R1
R2
SCR
OUT
(OUTA FOR
MAX6459)
CLEAR
OUT
(OUTA FOR
MAX6459)
IN+
1µF
GND
GND
Figure 9. Overvoltage Shutdown Circuit (with External Pass
MOSFET)
Figure 10. Overvoltage Shutdown Circuit (with SCR Fuse)
Window Detection
The MAX6458/MAX6459 include undervoltage and
overvoltage comparators for window detection (Figures
2 and 3). The circuit in Figure 11 shows the typical con-
figuration for this application. For the MAX6458, OUT
Applications Information
Undervoltage Lockout
Figure 8 shows the typical application circuit for detecting
an undervoltage event of a 5-cell Li+ battery stack.
Connect OUT of the MAX6457/MAX6458/MAX6460
(OUTA of the MAX6459) to the shutdown input of the DC-
DC converter to cut off power to the load in case of an
undervoltage event. Select R1 and R2 to set the trip volt-
asserts high when V
is within the selected “window.”
CC
When V
TRIPLOW
OUT asserts low.
falls below the lower limit of the window
) or exceeds the upper limit (V
CC
(V
),
TRIPHIGH
The MAX6459 features two independent open-drain
outputs: OUTA (for undervoltage events) and OUTB (for
age (see the Programming the Trip Voltage (V
) sec-
TRIP
tion). When the voltage of the battery stack decreases so
that V + drops below V - of the MAX6457–MAX6460,
overvoltage events). When V
is within the selected
CC
IN
TH
window, OUTA and OUTB assert high. When V
falls
then OUT (OUTA) goes low and disables the power sup-
ply to the load. When the battery charger restores the volt-
CC
below V
, OUTA asserts low while OUTB
TRIPLOW
age of the 5-cell stack so that V + > V +, OUT (OUTA)
IN
TH
goes high and the power supply resumes driving the load.
V
CC
Overvoltage Shutdown
The MAX6457–MAX6460 are ideal for overvoltage shut-
down applications. Figure 9 shows a typical circuit for
this application using a pass P-channel MOSFET. The
MAX6457–MAX6460 are powered directly from the sys-
tem voltage supply. Select R1 and R2 to set the trip volt-
V
CC
V
CC
R
PULLUP
OUT
MAX6458
ONLY
OUT
R1
R2
R3
age (see the Programming the Trip Voltage (V
)
TRIP
V
CC
IN+
IN-
section). When the supply voltage remains below the
selected threshold, a low logic level on OUT (OUTB for
MAX6459) turns on the p-channel MOSFET. In the case
of an overvoltage event, OUT (OUTB) asserts high, turns
off the MOSFET, and shuts down the power to the load.
MAX6458
MAX6459
R
R
PULLUP
PULLUP
OUTA
OUTA
OUTB
OUTB
MAX6459
ONLY
Figure 10 shows a similar application using a fuse and
a silicon-controlled rectifier (SCR). An overvoltage
event turns on the SCR and shorts the supply to
ground. The surge of current through the short circuit
blows the fuse and terminates the current to the load.
Select R3 so that the gate of the SCR is properly biased
when OUT (OUTB) goes high impedance.
GND
Figure 11. Window Detection
10
Maxim Integrated
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
remains high. When V
exceeds V
, OUTB
and
Example Calculations for Window
Detection
CC
TRIPHIGH
asserts low while OUTA remains high. V
TRIPLOW
V
are given by the following equations:
The following is an example for calculating R1, R2, and
R3 of Figure 11 for window detection. Select the upper
TRIPHIGH
R
⎛
⎞
and lower trip points (V
and V
).
TRIPLOW
TOTAL
TRIPHIGH
VTRIPLOW = VTH-
⎜
⎝
⎟
⎠
R2+R3
V
V
V
= 21V
CC
R
⎛
⎞
⎠
= 23.1V
= 18.9V
TRIPHIGH
TRIPLOW
TOTAL
VTRIPHIGH = VTH+
⎜
⎝
⎟
R3
For 5% hysteresis, V + = 1.228 and V - = 1.167.
TH
TH
where R
= R1 + R2 + R3.
TOTAL
1) Choose R
= 4.2MΩ = R1 + R2 + R3
TOTAL
Use the following steps to determine the values for R1,
R2, and R3.
2) Calculate R3
1) Choose a value for R
, the sum of R1, R2, and
TOTAL
V
× R
(1.228V) (4.2MΩ)
TH+
V
TOTAL
R3. Because the MAX6458/MAX6459 have very
high input impedance, R can be up to 5MΩ.
R3 =
=
23.1V
TRIPHIGH
TOTAL
= 223.273kΩ
3) Calculate R2
2) Calculate R3 based on R
upper trip point:
and the desired
TOTAL
VTH+ × RTOTAL
R3 =
VTRIPHIGH
V
OUT
(UP TO 28V)
V
CC
(4V TO 28V)
3) Calculate R2 based on R , R3, and the desired
TOTAL
lower trip point:
V
CC
R
PULLUP
V
× R
TOTAL
TH-
V
MAX6457–
MAX6460
OUT/
OUTA/
OUTB
OUT/
OUTA/
OUTB
R2 =
- R3
TRIPLOW
4) Calculate R1 based on R
, R3, and R2:
TOTAL
R1 = R
- R2 - R3
TOTAL
GND
Figure 13. Interfacing to Voltages Other than V
CC
V
V
CC
CC
V
CC
V
MON
V
CC
IN-
R
PULLUP
R
PULLUP
R1
MAX6457–
MAX6460
MAX6460
OUT
OUT
OUT
(OUTA)
OUT
IN+
REF
IN+
(OUTA FOR
MAX6459)
R1
R2
R2
GND
GND
V
NEG
Figure 14. Monitoring Negative Voltages
Figure 12. Monitoring Voltages Other than V
Maxim Integrated
CC
11
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Table 1. Factory-Trimmed Internal Hysteresis and Timeout Period Options
PART
SUFFIX
0A
0B
0C
3A
3B
3C
A
TIMEOUT OPTION
50µs
HYSTERESIS OPTION (%)
0.5
5
50µs
50µs
8.3
0.5
5
MAX6457UKD_ _ -T
MAX6458UKD_ _ -T
150ms
150ms
150ms
50µs
8.3
0.5
5
MAX6459UT_ -T
MAX6460UT-T
B
50µs
C
50µs
8.3
0.5
N/A
50µs
Selector Guide
PIN
COUNT
LATCHED NUMBER OF HYSTERESIS
TIMEOUT
PERIOD
PART
TOP MARK
COMPARATORS
OUTPUT
OUTPUTS
(%V
)
TH+
MAX6457UKD0A-T
MAX6457UKD3A-T
MAX6457UKD0B-T
MAX6457UKD3B-T
MAX6457UKD0C-T
MAX6457UKD3C-T
MAX6458UKD0A-T
MAX6458UKD3A-T
MAX6458UKD0B-T
MAX6458UKD3B-T
MAX6458UKD0C-T
MAX6458UKD3C-T
MAX6459UTA-T
5
5
5
5
5
5
5
5
5
5
5
5
6
6
6
6
✓
✓
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
1
0.5
50µs
150ms
50µs
AEAA
AANN
AANL
AANO
AANM
ADZZ
AANP
AANS
AANQ
AEAB
AANR
AANT
ABML
ABEJ
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
1
0.5
5
✓
✓
5
150ms
50µs
✓
8.3
8.3
0.5
0.5
5
✓
150ms
50µs
—
—
—
—
—
—
—
—
—
—
150ms
50µs
5
150ms
50µs
8.3
8.3
0.5
5
150ms
50µs
MAX6459UTB-T
50µs
MAX6459UTC-T
8.3
0.5
50µs
ABMM
ABEG
MAX6460UT-T
50µs
12
Maxim Integrated
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Interfacing to Voltages Other than V
CC
V
× R
TOTAL
TH-
V
The open-drain outputs of the MAX6457–MAX6460
allow the output voltage to be selected independent of
R2 =
- R3
TRIPLOW
V
V
. For systems requiring an output voltage other than
, connect the pullup resistor between OUT, OUTA, or
CC
CC
(1.167V) (4.2MΩ)
=
- 223.273kΩ
18.9V
OUTB and any desired voltage up to 28V (see Figure 13).
= 36.06kΩ
Monitoring Negative Voltages
4) Calculate R1
Figure 14 shows the typical application circuit for moni-
toring negative voltages (V
) using the MAX6460.
NEG
R1 = R
- R2 - R3
Select a value for R1 between 25kΩ and 1MΩ. Use the
TOTAL
following equation to select R2:
= 4.2MΩ - 223.273kΩ - 36.06kΩ
= 3.94067MΩ
-VNEG
R2 = R1 ×
VREF
Monitoring Voltages Other than V
The MAX6457–MAX6460 can monitor voltages other than
(Figure 12). Calculate V
Programming the Trip Voltage (V
CC
where V
= 2.25V and V
< 0. V + must always
REF
NEG IN
V
as shown in the
CC
TRIP
be within the specified operating range: 0 to V
.
CC
) section. The moni-
TRIP
tored voltage (V
) is independent of V . V + must
MON
CC IN
be within the specified operating range: 0 to V
.
CC
Pin Configurations
TOP VIEW
OUT
GND
IN+
1
2
3
5
4
V
OUT
GND
IN+
1
2
3
5
4
V
CC
CC
MAX6457
SOT23
MAX6459
SOT23
MAX6458
SOT23
MAX6460
SOT23
CLEAR
IN-
OUTA
GND
IN+
1
2
3
6
5
4
V
CC
OUT
GND
IN+
1
2
3
6
5
4
V
CC
OUTB
IN-
REF
IN-
Maxim Integrated
13
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Package Information
Chip Information
For the latest package outline information and land patterns (foot-
prints), go to www.maxim-integrated.com/packages. Note that
a “+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but the
drawing pertains to the package regardless of RoHS status.
PROCESS: BiCMOS
LAND
PATTERN NO.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE NO.
90-0174
90-0175
5 SOT23
6 SOT23
U5+1
U6+1
21-0057
21-0058
14
Maxim Integrated
MAX6457–MAX6460
High-Voltage, Low-Current Voltage Monitors in
SOT Packages
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
1
2
3
4
5
6
7/02
6/03
Initial release
—
Updated the Pin Description and Detailed Description sections.
Added lead-free notation to Ordering Information.
6, 8
12/05
1/07
1
Updated the Pin Description and Figures 5a, 9, 12.
6, 8, 10, 11, 13-16
3/09
Updated the Programming the Trip Voltage (V
Updated the Package Information table.
) section.
8
14
1
TRIP
7/12
12/12
Added MAX6459UT_/V+ to Ordering Information
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and
max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000 ________________________________ 15
© 2012 Maxim Integrated Products, Inc.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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