Maxim MAX16012TT-T Ultra-small, overvoltage protection/detection circuit Datasheet

19-3693; Rev 4; 9/08
Ultra-Small, Overvoltage Protection/
Detection Circuits
The MAX16010–MAX16014 is a family of ultra-small, lowpower, overvoltage protection circuits for high-voltage,
high-transient systems such as those found in automotive,
telecom, and industrial applications. These devices operate over a wide 5.5V to 72V supply voltage range, making
them also suitable for other applications such as battery
stacks, notebook computers, and servers.
The MAX16010 and MAX16011 offer two independent
comparators for monitoring both undervoltage and
overvoltage conditions. These comparators offer opendrain outputs capable of handling voltages up to 72V.
The MAX16010 features complementary enable inputs
(EN/EN), while the MAX16011 features an active-high
enable input and a selectable active-high/low OUTB
output.
The MAX16012 offers a single comparator and an independent reference output. The reference output can be
directly connected to either the inverting or noninverting
input to select the comparator output logic.
The MAX16013 and MAX16014 are overvoltage protection circuits that are capable of driving two p-channel
MOSFETs to prevent reverse-battery and overvoltage
conditions. One MOSFET (P1) eliminates the need for
external diodes, thus minimizing the input voltage drop.
The second MOSFET (P2) isolates the load or regulates
the output voltage during an overvoltage condition. The
MAX16014 keeps the MOSFET (P2) latched off until the
input power is cycled.
The MAX16010 and MAX16011 are available in small
8-pin TDFN packages, while the MAX16012/MAX16013/
MAX16014 are available in small 6-pin TDFN packages.
These devices are fully specified from -40°C to +125°C.
Features
o Wide 5.5V to 72V Supply Voltage Range
o Open-Drain Outputs Up to 72V
(MAX16010/MAX16011/MAX16012)
o Fast 2µs (max) Propagation Delay
o Internal Undervoltage Lockout
o p-Channel MOSFET Latches Off After an
Overvoltage Condition (MAX16014)
o Adjustable Overvoltage Threshold
o -40°C to +125°C Operating Temperature Range
o Small 3mm x 3mm TDFN Package
Ordering Information
PART*
PIN-PACKAGE
MAX16010TA_-T
-40°C to +125°C
8 TDFN-EP**
MAX16011TA_-T
-40°C to +125°C
8 TDFN-EP**
MAX16012TT-T
-40°C to +125°C
6 TDFN-EP**
MAX16013TT-T
-40°C to +125°C
6 TDFN-EP**
MAX16014TT-T
-40°C to +125°C
6 TDFN-EP**
Note: Replace the “_” with “A” for 0.5% hysteresis, “B” for 5%
hysteresis, and “C” for 7.5% hysteresis.
*Replace -T with +T for lead-free packages.
**EP = Exposed pad.
Typical Operating Circuit
P1
Applications
Automotive
TEMP RANGE
P2
VBATT
Industrial
48V Telecom/Server/Networking
2MΩ*
FireWire®
Notebook Computers
GATE1
Multicell Battery-Stack Powered Equipment
VCC
GATE2
R1
FireWire is a registered trademark of Apple, Inc.
SET
R2
Pin Configurations appear at end of data sheet.
MAX16013
MAX16014
GND
*OPTIONAL
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX16010–MAX16014
General Description
MAX16010–MAX16014
Ultra-Small, Overvoltage Protection/
Detection Circuits
ABSOLUTE MAXIMUM RATINGS
(All pins referenced to GND, unless otherwise noted.)
VCC .........................................................................-0.3V to +80V
EN, EN, LOGIC...........................................-0.3V to (VCC + 0.3V)
INA+, INB-, IN+, IN-, REF, SET ..............................-0.3V to +12V
OUTA, OUTB, OUT.................................................-0.3V to +80V
GATE1, GATE2 to VCC ...........................................-12V to +0.3V
GATE1, GATE2...........................................-0.3V to (VCC + 0.3V)
Current Sink/Source (all pins) .............................................50mA
Continuous Power Dissipation (TA = +70°C)
6-Pin TDFN (derate 18.2mW/°C above +70°C) .........1455mW
8-Pin TDFN (derate 18.2mW/°C above +70°C) .........1455mW
Operating Temperature Range .........................-40°C to +125°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-60°C to +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
(VCC = 14V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
Input Supply Current
VCC Undervoltage Lockout
SYMBOL
CONDITIONS
VCC
ICC
VUVLO
VTH-
TYP
5.5
No load
VCC = 48V
25
40
5
5.25
VCC rising, part enabled, VINA+ = 2V, OUTA
deasserted (MAX16010/MAX16011),
VIN = 2V, VOUT deasserted (MAX16012),
VSET = 0V, GATE2 = VCLMP (MAX16013/
MAX16014)
4.75
1.215
1.245
1.265
0.5% hysteresis, MAX16010/MAX16011
1.21
1.223
1.26
5.0% hysteresis, MAX16010/MAX16011/
MAX16013/MAX16014
1.15
1.18
1.21
7.5% hysteresis MAX16010/MAX16011
1.12
1.15
1.18
Threshold-Voltage Hysteresis
MAX16010TAB/MAX16011TAB/
MAX16013/MAX16014
5.0
SET/IN_ Input Current
SET/IN_ = 2V
MAX16010TAC/MAX16011TAC
IN_ Operating Voltage Range
tSTART
VCC rising from 0 to 5.5V
IN_ to OUT/SET to GATE2
Propagation Delay
tPROP
IN_/SET rising from (VTH - 100mV) to
(VTH + 100mV) or falling from (VTH +
100mV) to (VTH - 100mV) (no load)
OUT_ Output-Voltage Low
VOL
µA
V
V
%
7.5
-100
+100
0
Startup Response Time
2
V
30
0.5
ILEAK
UNITS
72.0
20
MAX16010TAA/MAX16011TAA
OUT_ Leakage Current
MAX
VCC = 12V
VTH+
INA+/INB-/SET Threshold Voltage
MIN
4
100
VCC ≥ 5.5V, ISINK = 3.2mA
nA
V
µs
2
µs
0.4
V
VCC ≥ 2.8V, ISINK = 100µA
0.4
V
OUT_ = 72V
500
nA
_______________________________________________________________________________________
Ultra-Small, Overvoltage Protection/
Detection Circuits
(VCC = 14V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
VIL
EN/EN, LOGIC Input Voltage
UNITS
0.4
VIH
V
1.4
EN/EN, LOGIC Input Current
1
EN/EN, LOGIC Pulse Width
2
µA
10
µs
VCC to GATE_ Output Low
Voltage
IGATE_SINK = 75µA, IGATE_SOURCE = 1µA,
VCC = 14V
7
11
V
VCC to GATE_ Clamp Voltage
VCC = 24V
12
18
V
MAX16012
Reference Output Voltage
VREF
Reference Short-Circuit Current
No load
ISHORT
1.275
REF = GND
Reference Load Regulation
Input Offset Voltage
1.3
1.320
V
100
Sourcing, 0 ≤ IREF ≤ 1µA
0.1
Sinking, -1µA ≤ IREF ≤ 0
0.1
VCM = 0 to 2V
µA
mV/µA
-12.5
+12.5
mV
Input Offset Current
3
nA
Input Hysteresis
8
mV
Common-Mode Voltage Range
CMVR
Common-Mode Rejection Ratio
CMRR
DC
0
70
2.0
dB
V
Comparator Power-Supply
Rejection Ratio
PSRR
MAX16012, DC
70
dB
Note 1: 100% production tested at TA = +25°C and TA = +125°C. Specifications at TA = -40°C are guaranteed by design.
Typical Operating Characteristics
(VIN = 14V, TA = +25°C, unless otherwise noted.)
25
15
MAX16012
IN+ = IN- = GND
MAX16010/MAX16011
INA+ = INB- = GND
OUTPUTS ENABLED
26.40
26.35
26.30
26.25
26.20
26.15
26.10
25
35
40
VGATE
30
20
VCC - VGATE
10
0
26.00
15
MAX16013/MAX16014
SET = GND, EN = VCC
50
26.05
10
5
60
MAX16010 toc03
MAX16013/MAX16014
SET = GND, EN = VCC
GATE VOLTAGE (V)
SUPPLY CURRENT (µA)
30
26.45
SUPPLY CURRENT (µA)
MAX16013/MAX16014
SET = GND, EN = VCC
20
26.50
MAX16010 toc01
40
35
GATE VOLTAGE
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. TEMPERATURE
MAX16010 toc02
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
45
55
SUPPLY VOLTAGE (V)
65
75
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
5
15
25
35
45
55
65
75
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
3
MAX16010–MAX16014
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(VIN = 14V, TA = +25°C, unless otherwise noted.)
5.2
5.1
5.0
RISING
4.9
4.8
4.7
4.6
FALLING
4.5
INA+/INB-/SET RISING
EN = VCC
1.29
10.0
1.28
1.27
9.9
1.26
1.25
1.24
MAX16013/MAX16014
SET = GND, EN = VCC
9.8
(VCC - VGATE) (V)
5.3
1.30
MAX16010 toc05
INA+/INB-/SET = GND
EN = VCC
INA+/INB-/SET THRESHOLD (V)
MAX16010 toc04
5.5
5.4
GATE VOLTAGE
vs. TEMPERATURE
INA+/INB-/SET THRESHOLD
vs. TEMPERATURE
9.7
9.6
9.5
9.4
1.23
9.3
1.22
9.2
1.21
9.1
9.0
1.20
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
STARTUP WAVEFORM
(ROUT = 100Ω, CIN = 10µF, COUT = 10nF)
STARTUP WAVEFORM
(ROUT = 100Ω, CIN = 10µF, COUT = 10nF)
MAX16010 toc08
MAX16010 toc07
VCC
1V/div
VCC
10V/div
VGATE
10V/div
VGATE
5V/div
VOUT
10V/div
VOUT
10V/div
VEN = 0 TO 2V
20µs/div
200µs/div
OVERVOLTAGE SWITCH FAULT
(ROUT = 100Ω, CIN = 80µF, COUT = 10nF)
OVERVOLTAGE LIMIT
(ROUT = 100Ω, CIN = 80µF, COUT = 10nF)
MAX16010 toc09
MAX16010 toc10
VCC
20V/div
VCC
20V/div
VGATE
20V/div
VGATE
20V/div
VOUT
20V/div
VIN = 12V TO 40V, TRIP THRESHOLD = 28V
1ms/div
4
MAX16010 toc06
UVLO THRESHOLD
vs. TEMPERATURE
UVLO THRESHOLD (V)
MAX16010–MAX16014
Ultra-Small, Overvoltage Protection/
Detection Circuits
VOUT
20V/div
VIN = 12V TO 40V
TRIP THRESHOLD = 28V
1ms/div
_______________________________________________________________________________________
Ultra-Small, Overvoltage Protection/
Detection Circuits
MAX16010
MAX16011
MAX16012
MAX16013
MAX16014
PIN
1
1
1
1
VCC
Positive-Supply Input Voltage. Connect VCC to a 5.5V to 72V supply.
2
2
2
2
GND
Ground
3
—
—
—
EN
NAME
4
4
—
—
OUTB
5
5
—
—
INB-
FUNCTION
Active-Low Enable Input. Drive EN low to turn on the voltage detectors. Drive EN high to force the
OUTA and OUTB outputs low. EN is internally pulled up to VCC. Connect EN to GND if not used.
Open-Drain Monitor B Output. Connect a pullup resistor from OUTB to VCC. OUTB goes low when
INB- exceeds VTH+ and goes high when INB- drops below VTH- (with LOGIC connected to GND for
the MAX16011). Drive LOGIC high to reverse OUTB’s logic state. OUTB is usually used as an
overvoltage output. OUTB goes low (LOGIC = low) or high (LOGIC = high) when VCC drops below
the UVLO threshold voltage.
Adjustable Voltage Monitor Threshold Input
Active-High ENABLE Input. For the MAX16010/MAX16011, drive EN high to turn on the voltage
detectors. Drive EN low to force OUTA low and OUTB low (LOGIC = low) or high (LOGIC = high). For
the MAX16013/MAX16014, drive EN high to enhance the p-channel MOSFET (P2), and drive EN low
to turn off the MOSFET. EN is internally pulled down to GND. Connect EN to VCC if not used.
6
6
—
5
EN
7
7
—
—
OUTA
Open-Drain Monitor A Output. Connect a pullup resistor from OUTA to VCC. OUTA goes low when
INA+ drops below VTH- and goes high when INA+ exceeds VTH+. OUTA is usually used as an
undervoltage output. OUTA also goes low when VCC drops below the UVLO threshold voltage.
8
8
—
—
INA+
Adjustable Voltage Monitor Threshold Input
OUTB Logic-Select Input. Connect LOGIC to GND or VCC to configure the OUTB logic. See the
LOGIC
MAX16011 output logic table.
—
3
—
—
—
—
3
—
OUT
—
—
4
—
IN-
Inverting Comparator Input
—
—
5
—
REF
Internal 1.30V Reference Output. Connect REF to IN+ for active-low output. Connect REF to IN- for
active-high output. REF can source and sink up to 1µA. Leave REF floating if not used. REF output is
stable with capacitive loads from 0 to 50pF.
—
—
6
—
IN+
Noninverting Comparator Input
Open-Drain Comparator Output. Connect a pullup resistor from OUT to VCC. OUT goes low when
IN+ drops below IN-. OUT goes high when IN+ exceeds IN-.
Gate-Driver Output. Connect GATE2 to the gate of an external p-channel MOSFET pass switch.
GATE2 is driven low to the higher of VCC - 10V or GND during normal operations and quickly shorted
GATE2 to VCC during an overvoltage condition (SET above the internal threshold). GATE2 is shorted to VCC
when the supply voltage goes below the UVLO threshold voltage. GATE2 is shorted to VCC when EN
is low.
—
—
—
3
—
—
—
4
SET
—
—
—
6
GATE1
—
—
—
—
EP
Device Overvoltage Threshold Adjustment Input. Connect SET to an external resistive divider network
to adjust the desired overvoltage disable or overvoltage limit threshold (see the Typical Application
Circuit and Overvoltage Limiter section).
Gate-Driver Output. Connect GATE1 to the gate of an external p-channel MOSFET to provide low
drop reverse voltage protection.
Exposed Pad. Connect EP to GND.
_______________________________________________________________________________________
5
MAX16010–MAX16014
Pin Description
MAX16010–MAX16014
Ultra-Small, Overvoltage Protection/
Detection Circuits
Voltage Monitoring
+48V
R1
EN
INA+
VCC
OUTA
OUTB
R2
EN
IN
DC-DC
REGULATOR
MAX16010
INBR3
GND EN
The MAX16010/MAX16011 include undervoltage and
overvoltage comparators for window detection (see
Figure 1). OUT_ asserts high when the monitored voltage is within the selected “window.” OUTA asserts low
when the monitored voltage falls below the lower
(VTRIPLOW) limit of the window, or OUTB asserts low if
the monitored voltage exceeds the upper limit
(VTRIPHIGH). The application in Figure 1 shows OUT_
enabling the DC-DC converter when the monitored voltage is in the selected window.
The resistor values R1, R2, and R3 can be calculated
as follows:
⎛ R
⎞
VTRIPLOW = VTH − ⎜ TOTAL ⎟
⎝ R2 + R 3 ⎠
Figure 1. MAX16010 Monitor Circuit
Detailed Description
The MAX16010–MAX16014 is a family of ultra-small, lowpower, overvoltage protection circuits for high-voltage,
high-transient systems such as those found in automotive, telecom, and industrial applications. These devices
operate over a wide 5.5V to 72V supply voltage range,
making them also suitable for other applications such as
battery stacks, notebook computers, and servers.
The MAX16010 and MAX16011 offer two independent
comparators for monitoring both undervoltage and
overvoltage conditions. These comparators offer opendrain outputs capable of handling voltages up to 72V.
The MAX16010 features complementary enable inputs
(EN/EN), while the MAX16011 features an active-high
enable input and a selectable active-high/low OUTB
output.
The MAX16012 offers a single comparator and an independent reference output. The reference output can be
directly connected to either the inverting or noninverting input to select the comparator output logic.
The MAX16013 and MAX16014 are overvoltage protection circuits that are capable of driving two p-channel
MOSFETs to prevent reverse battery and overvoltage
conditions. One MOSFET (P1) eliminates the need for
external diodes, thus minimizing the input voltage drop.
While the second MOSFET (P2) isolates the load or regulates the output voltage during an overvoltage condition. The MAX16014 keeps the MOSFET (P2) latched
off until the input power is cycled.
6
⎛R
⎞
VTRIPHIGH = VTH + ⎜ TOTAL ⎟
⎝ R3 ⎠
where RTOTAL = R1 + R2 + R3.
Use the following steps to determine the values for R1,
R2, and R3.
1) Choose a value for RTOTAL, the sum of R1, R2, and
R3. Because the MAX16010/MAX16011 have very
high input impedance, RTOTAL can be up to 5MΩ.
2) Calculate R3 based on R TOTAL and the desired
upper trip point:
R3 =
VTH + × R TOTAL
VTRIPHIGH
3) Calculate R2 based on RTOTAL, R3, and the desired
lower trip point:
R2 =
VTH − × R TOTAL
− R3
VTRIPLOW
4) Calculate R1 based on RTOTAL, R3, and R2:
R1 = RTOTAL - R2 - R3
The MAX16012 has both inputs of the comparator available with an integrated 1.30V reference (REF). When the
voltage at IN+ is greater than the voltage at IN- then OUT
goes high. When the voltage at IN- is greater than the
voltage at IN+ then OUT goes low. Connect REF to IN+
or IN- to set the reference voltage value. Use an external
resistive divider to set the monitored voltage threshold.
_______________________________________________________________________________________
Ultra-Small, Overvoltage Protection/
Detection Circuits
P1
VCC
R1
P2
VBATT
RPULLUP
IN+
VCC
GATE1
GATE2
R2
REF
MAX16012
OUT
OUT
R1
MAX16013
SET
IN-
R2
GND
GND
Figure 2. Typical Operating Circuit for the MAX16012
Figure 3. Overvoltage Limiter Protection
The MAX16013/MAX16014 can be configured as an
overvoltage switch controller to turn on/off a load (see
the Typical Application Circuit). When the programmed
overvoltage threshold is tripped, the internal fast comparator turns off the external p-channel MOSFET (P2),
pulling GATE2 to VCC to disconnect the power source
from the load. When the monitored voltage goes below
the adjusted overvoltage threshold, the MAX16013
enhances GATE2, reconnecting the load to the power
source (toggle ENABLE on the MAX16014 to reconnect
the load). The MAX16013 can be configured as an
overvoltage limiter switch by connecting the resistive
divider to the load instead of VCC (Figure 3). See the
Overvoltage Limiter section.
Supply Voltage
Connect a 5.5V to 72V supply to VCC for proper operation. For noisy environments, bypass VCC to GND with a
0.1µF or greater capacitor. When VCC falls below the
UVLO voltage the following states are present (Table 1).
Table 1. UVLO State (VCC < VUVLO)
PART
OUTA
MAX16010
Low
MAX16011
MAX16012
MAX16013
MAX16014
OUTB
Hysteresis
Hysteresis adds noise immunity to the voltage monitors
and prevents oscillation due to repeated triggering
when the monitored voltage is near the threshold trip
voltage. The hysteresis in a comparator creates two trip
points: one for the rising input voltage (VTH+) and one
for the falling input voltage (VTH-). These thresholds are
shown in Figure 4.
Enable Inputs (EN or EN)
The MAX16011 offers an active-high enable input (EN),
while the MAX16010 offers both an active-high enable
input (EN) and active-low enable input (EN). For the
MAX16010, drive EN low or EN high to force the output
low. When the device is enabled (EN = high and EN =
low) the state of OUTA and OUTB depends on INA+
and INB- logic states.
VHYST
VTH+
VIN+
OUT
GATE2
Low
—
—
Low
Low, LOGIC = low
High, LOGIC = high
—
—
—
—
Low
—
VTH-
VCC
VOUT
tPROP
tPROP
tPROP
0V
—
—
—
High
Figure 4. Input and Output Waveforms
_______________________________________________________________________________________
7
MAX16010–MAX16014
VBATT
MAX16010–MAX16014
Ultra-Small, Overvoltage Protection/
Detection Circuits
Input Transients Clamping
Table 2. MAX16011 Output Logic
LOGIC
INA+
INB-
OUTA
OUTB
Low
Low
> VTH+
> VTH+
High
Impedance
Low
< VTH-
< VTH-
Low
High
Impedance
High
> VTH+
> VTH+
High
Impedance
High
Impedance
High
< VTH-
< VTH-
Low
Low
For the MAX16011, drive EN low to force OUTA low,
OUTB low when LOGIC = low, and OUTB high when
LOGIC = high. When the device is enabled (EN = high)
the state of OUTA and OUTB depends on the INA+,
INB-, and LOGIC input (see Table 2).
For the MAX16013/MAX16014, drive EN low to pull
GATE2 to VCC, turning off the p-channel MOSFET (P2).
When the device is enabled (EN = high), GATE2 is
pulled to the greater of (VCC - 10V) or GND turning on
the external MOSFET (P2).
Applications Information
Load Dump
Most automotive applications are powered by a multicell, 12V lead-acid battery with a voltage between 9V
and 16V (depending on load current, charging status,
temperature, battery age, etc.). The battery voltage is
distributed throughout the automobile and is locally
regulated down to voltages required by the different
system modules. Load dump occurs when the alternator is charging the battery and the battery becomes
disconnected. Power in the alternator inductance flows
into the distributed power system and elevates the voltage seen at each module. The voltage spikes have rise
times typically greater than 5ms and decays within several hundred milliseconds but can extend out to 1s or
more depending on the characteristics of the charging
system. These transients are capable of destroying
sensitive electronic equipment on the first fault event.
The MAX16013/MAX16014 provide the ability to disconnect the load from the charging system during an
overvoltage condition to protect the module. In addition, the MAX16013 can be configured in a voltage-limiting mode. This allows continuous operation while
providing overvoltage protection. See the Overvoltage
Limiter section.
8
When the external MOSFET is turned off during an
overvoltage occurrence, stray inductance in the power
path may cause voltage ringing to exceed the
MAX16013/MAX16014 absolute maximum input (VCC)
supply rating. The following techniques are recommended to reduce the effect of transients:
•
Minimize stray inductance in the power path using
wide traces, and minimize loop area including the
power traces and the return ground path.
•
Add a zener diode or transient voltage suppresser
(TVS) rated below VCC absolute maximum rating
(Figure 3).
Overvoltage Limiter
When operating in overvoltage-limiter mode, the
MAX16013 drives the external p-channel MOSFET (P2),
resulting in the external MOSFET operating as a voltage
regulator.
During normal operation, GATE2 is pulled to the greater
of (VCC - 10V) or GND. The external MOSFET’s drain
voltage is monitored through a resistor-divider between
the P2 output and SET. When the output voltage rises
above the adjusted overvoltage threshold, an internal
comparator pulls GATE2 to VCC. When the monitored
voltage goes below the overvoltage threshold, the
p-channel MOSFET (P2) is turned on again. This
process continues to keep the voltage at the output regulated to within approximately a 5% window. The output
voltage is regulated during the overvoltage transients
and the MOSFET (P2) continues to conduct during the
overvoltage event, operating in switched-linear mode.
Caution must be exercised when operating the
MAX16013 in voltage-limiting mode for long durations
due to the MOSFET’s power dissipation consideration
(see the MOSFET Selection and Operation section).
MOSFET Selection and Operation
(MAX16013 and MAX16014)
Most battery-powered applications must include reverse
voltage protection. Many times this is implemented with a
diode in series with the battery. The disadvantage in
using a diode is the forward voltage drop of the diode,
which reduces the operating voltage available to downstream circuits (V LOAD = V BATTERY - V DIODE ). The
MAX16013 and MAX16014 include high-voltage GATE1
drive circuitry allowing users to replace the high-voltagedrop series diode with a low-voltage-drop MOSFET
device (as shown in the Typical Operating Circuit and
Figure 3). The forward voltage drop is reduced to ILOAD
x RDS-ON of P1. With a suitably chosen MOSFET, the
voltage drop can be reduced to millivolts.
_______________________________________________________________________________________
Ultra-Small, Overvoltage Protection/
Detection Circuits
During overvoltage conditions, P2 is either turned completely off (overvoltage-switch mode) or cycled off-onoff (voltage-limiter mode). Care should be taken to
place P2 (and its internal drain-to-source diode) in the
correct orientation for proper overvoltage protection
operation. During voltage-limiter mode, the drain of P2
is limited to the adjusted overvoltage threshold, while
the battery (VCC) voltage rises. During prolonged overvoltage events, P2 temperature can increase rapidly
due to the high power dissipation. The power dissipated by P2 is:
P2 = VDS-P2 x ILOAD
= (VCC - VOV-ADJUSTED) x ILOAD
where VCC ~ VBATTERY and VOV-ADJUSTED is the desired
load limit voltage. For prolonged overvoltage events with
high P2 power dissipation, proper heatsinking is required.
Adding External Pullup Resistors
It may be necessary to add an external resistor from
V CC to GATE1 to provide enough additional pullup
capability when the GATE1 input goes high. The
GATE_ output can only source up to 1µA current. If the
source current is less than 1µA, no external resistor
may be necessary. However, to improve the pullup
capability of the GATE_ output when it goes high, connect an external resistor between VCC and the GATE_.
The application shows a 2MΩ resistor, which is large
enough not to impact the sinking capability of the
GATE_ (during normal operation) while providing
enough pullup during an overvoltage event. With an
11V (worst case) V CC -to-gate clamp voltage and a
sinking current of 75µA, the smallest resistor should be
11V/75µA, or about 147kΩ. However, since the GATE_
is typically low most of the time, a higher value should
be used to reduce overall power consumption.
_______________________________________________________________________________________
9
MAX16010–MAX16014
In normal operating mode, internal GATE1 output circuitry enhances P1 to a 10V gate-to-source (VGS) for
11V < V CC < 72V. The constant 10V enhancement
ensures P1 operates in a low RDS-ON mode, but the
gate-source junction is not overstressed during highbattery-voltage application or transients (many MOSFET
devices specify a ±20V VGS absolute maximum). As
VCC drops below 10V GATE1 is limited to GND, reducing P1 VGS to VCC - GND. In normal operation the P1
power dissipation is very low:
P1 = ILOAD2 x RDS-ON
During reverse-battery applications, GATE1 is limited to
GND and the P1 gate-source junction is reverse
biased. P1 is turned off and neither the MAX16013/
MAX16014 nor the load circuitry is exposed to the
reverse-battery voltage. Care should be taken to place
P1 (and its internal drain-to-source diode) in the correct
orientation for proper reverse battery operation.
P2 protects the load from input overvoltage conditions.
During normal operating modes (the monitored voltage
is below the adjusted overvoltage threshold), internal
GATE2 output circuitry enhances P2 to a 10V gate-tosource (VGS) for 11V < VCC < 72V. The constant 10V
enhancement ensures P2 operates in a low RDS-ON
mode but the gate-to-source junction is not overstressed during high-battery-voltage applications
(many pFET devices specify a ±20V VGS absolute maximum). As VCC drops below 10V, GATE2 is limited to
GND, reducing P2 VGS to VCC - GND. In normal operation, the P2 power dissipation is very low:
P2 = ILOAD2 x RDS-ON
Ultra-Small, Overvoltage Protection/
Detection Circuits
MAX16010–MAX16014
Functional Diagrams
VCC
REGULATOR
VCC
REGULATOR
~4V
~4V
MAX16011
MAX16010
OUTA
INA+
OUTA
INA+
HYST
HYST
OUTB
INB-
OUTB
INB-
HYST
HYST
1.23V
1.23V
ENABLE CIRCUITRY
GND
ENABLE
CIRCUITRY
EN
GND
EN
Figure 5. MAX16010 Functional Diagram
OUTB
LOGIC
LOGIC
EN
Figure 6. MAX16011 Functional Diagram
VCC
VCC
REGULATOR
~4V
SET
MAX16012
GATE2
OUT
IN-
HYST
1.23V
IN+
REF
GATE1
1.30V
MAX16013
MAX16014
ENABLE
CIRCUITRY
LATCH
CLEAR
GND
GND
Figure 7. MAX16012 Functional Diagram
10
EN
Figure 8. MAX16013/MAX16014 Functional Diagram
______________________________________________________________________________________
Ultra-Small, Overvoltage Protection/
Detection Circuits
TOP VIEW
INA+
OUTA
EN
INB-
INA+
OUTA
EN
INB-
8
7
6
5
8
7
6
5
MAX16010
MAX16011
1
2
3
4
VCC
GND
EN
OUTB
1
2
VCC
TDFN (3mm x 3mm)
4
GND LOGIC OUTB
TDFN (3mm x 3mm)
IN+
REF
IN-
GATE1
EN
SET
6
5
4
6
5
4
MAX16012
MAX16013
MAX16014
1
2
3
VCC
GND
OUT
TDFN (3mm x 3mm)
1
2
3
VCC
GND
GATE2
TDFN (3mm x 3mm)
Package Information
Chip Information
PROCESS: BiCMOS
3
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
6 TDFN
T633-2
21-0137
8 TDFN
T833-2
21-0137
______________________________________________________________________________________
11
MAX16010–MAX16014
Pin Configurations
MAX16010–MAX16014
Ultra-Small, Overvoltage Protection/
Detection Circuits
Revision History
REVISION
NUMBER
REVISION
DATE
DESCRIPTION
0
6/05
Initial release
1
12/05
Removed future product designation for MAX16010/MAX16011
2
1/07
Edited Figure 7
3
12/07
Fixed text in Voltage Monitoring section and updated Package Outline
4
9/08
Revised Figures 6 and 8.
PAGES
CHANGED
—
1, 12
1, 10, 12
6, 12
10
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
© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
Similar pages