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MAX15068
General Description
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
The MAX15068 offers ORing function and hot-swap
features for two input-supply-rail applications requiring the
safe insertion and removal of circuit line cards from a live
backplane. The device integrates dual ORing MOSFET
controllers, a single hot-swap controller, electronic circuitbreaker protection, and power monitoring in a single
package. The device operates on 2.9V to 18V supply
voltages.
The device regulates the forward voltage drop across the
ORing MOSFETs to ensure smooth current transfer from
one supply to the other without oscillation. The ORing
MOSFET turns on quickly to reduce the load voltage
drop during supply switchover. If the input supply fails
or is shorted, a fast turn-off minimizes reverse-current
transients.
The device implements a foldback current limit during hotswap startup in order to control inrush current, thereby
keeping the hot-swap MOSFET under safe operating area
(SOA). After the hot-swap startup cycle is completed, onchip comparators provide active current-limit protection
against short-circuit and overcurrent faults. The load is
disconnected from the input quickly in the event of a fault
condition.
The device provides a current-sense amplifier output. A
voltage proportional to the current delivered to the system
can be read directly at the IPMON pin.
The device is factory-calibrated to deliver accurate
overcurrent protection with ±5% accuracy. During an
overcurrent-fault condition, the device enters an autoretry
mode. The device features an adjustable slew-rate control
during startup. Additional features include power-good
and fault-indicator outputs.
The MAX15068 is available in a 20-pin, (4mm x 5mm)
TQFN package and is specified from a -40°C to +125°C
operating temperature range.
19-6872; Rev 3; 10/19
Benefits and Features
●● 2.9V to 18V Operating Voltage Range (ORing and
Hot Swap)
●● Seamless Power Transition of Redundant Supplies
●● Controls n-Channel MOSFETs
●● < 0.5µs Reverse Turn-Off Time
●● Precision Current Monitoring
●● Adjustable Slew-Rate Control
●● Adjustable Current-Limit Fault Delay
●● Adjustable Circuit-Breaker Current Threshold
●● Inrush Current Regulated at Startup
●● Adjustable Undervoltage Lockout
●● Small (4mm x 5mm) TQFN Package
Applications
●●
●●
●●
●●
●●
●●
Baseband Station
Redundant Power Supplies
Supply Holdup
Computer Systems and Servers
Telecom Networks
Storage Bridge Bay
Ordering Information appears at end of data sheet.
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Absolute Maximum Ratings
IN1, IN2 to GND........................................................-1V to +24V
PG, EN, FAULT, CSN to GND...............................-0.3V to +24V
CSP to GND.............................Max (-0.3V, VIN_ - 0.6V) to +24V
VS to GND................................................................-0.3V to +6V
ON, PC, IPMON, CB, CDLY to GND...........-0.3V to (VS + 0.3V)
CSP to CSN..........................................................-0.3V to +0.3V
OUT to GND...........................................................-0.3V to +24V
GATE to GND.........................................................-0.3V to +36V
GATE to OUT.........................................................-0.3V to +20V
CP1 to GND...........................................................-0.3V to +36V
CP1 to IN1..............................................................-0.3V to +14V
CP2 to GND...........................................................-0.3V to +36V
CP2 to IN2..............................................................-0.3V to +14V
OG1..............................................(VIN1 - 0.3V) to (VCP1 + 0.3V)
OG2..............................................(VIN2 - 0.3V) to (VCP2 + 0.3V)
Current into EN, PG, FAULT...............................................20mA
Continuous Power Dissipation (TA = +70°C)
20-Pin TQFN (derate 30mW/ºC above +70°C)..........2400mW
Operating Temperature Range.......................... -40°C to +125°C
Junction Temperature.......................................................+150°C
Storage Temperature Range............................. -65°C to +150°C
Lead Temperature (soldering, 10s).................................. +300°C
Soldering Temperature (reflow)........................................+260°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.
Package Information
PACKAGE TYPE: 20-PIN TQFN
Package Code
T2045+1C
Outline Number
21-0726
Land Pattern Number
90-100091
THERMAL RESISTANCE, FOUR-LAYER BOARD
Junction to Ambient (θJA)
33.5°C/W
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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.
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board.
For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
Electrical Characteristics
(VIN1 = VIN2 = 12V, CIN1 = CIN2 = CVS = 1µF, TA = -40°C to +125°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SUPPLY VOLTAGE
Input Supply Voltage
VIN
Input Supply Current
IIN
Internal LDO Output Voltage
2.9
18
Current monitor
4.8
18
4
VS
VS Undervoltage Lockout
VUVLO
VS Undervoltage-Lockout
Hysteresis
VUVLO_HYS
CSP Undervoltage Lockout
VCSP_UVLO
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Hot swap and ORing
VS rising
V
mA
4.8
5
5.25
V
2.5
2.65
2.8
V
0.07
V
VCSP rising
2.4
2.49
2.58
VCSP falling
2.25
2.35
2.42
V
Maxim Integrated │ 2
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Electrical Characteristics (continued)
(VIN1 = VIN2 = 12V, CIN1 = CIN2 = CVS = 1µF, TA = -40°C to +125°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
ORing MOSFET Forward
Regulation Voltage (VIN_ - VCSP)
VFWD_REG
ORing MOSFET Reverse Bias
Turn-Off Voltage
VREV_OFF
ORing MOSFET Reverse Bias
Turn-On Voltage
CONDITIONS
MIN
TYP
MAX
UNITS
7.5
10
12.5
mV
VIN_- VCSP, VCSP rising (VCSP > VIN_),
VOG_ goes low
-25
-20
-15
mV
VREV_ON
VIN_ - VCSP, VCSP falling, (VIN_ > VCSP_),
VOG_ goes to forward regulation
-20
-15
-10
mV
ORing MOSFET Reverse Bias
Hysteresis Voltage
VREV_HYS
VREV_OFF - VREV_ON
Turn-Off Switch Resistance
RDS_OFF
VIN_- VCSP = -50mV, I = 50mA
Turn-On Switch Resistance
RDS_ON
VIN_- VCSP_ = 120mV, I = 70mA
ORing MOSFET Gate Drive
(VOG_ - VIN_)
VOG_
2.9V < VIN_< 18V
ORing MOSFET Fast Turn-On
Threshold
VFWD_ON
VIN_- VCSP rising
80
mV
ORing MOSFET Fast Turn-Off
VFWD_OFF
VIN_- VCSP falling, VOG_ goes to forward
regulation
40
mV
µs
ORING
5.2
5
mV
0.8
Ω
2
Ω
11
12
V
ORing MOSFET Turn-On Delay
tON_OG_
CGATE = 10nF, VIN_ - VCSP = +0.05V
20
ORing MOSFET Turn-Off Delay
tOFF_OG_
CGATE = 10nF, VIN_ - VCSP = -0.05V,
VOG_ = 0.1 x (VCP_ - VIN_)
300
500
ns
tLH_DLY
VPC falling edge to VOG2 going high
40
65
µs
VCB_TH
VCSP - VCSN
PC to OG2 Delay
HOT SWAP
Circuit-Breaker Accuracy
Active Current-Limit Sense
Voltage
VACL
Fast Comparator Threshold
VFC_TH
VCSP - VCSN
Fast Comparator Response
Time
tFC_DLY
GATE Off Delay
GATE Propagation Delay
tOFF_GATE
tON_GATE_PD
GATE Drive Voltage
(VGATE - VOUT)
VGATE
GATE Pullup Current
IGATE_ON
www.maximintegrated.com
VCB = 0V
32.9
35
37.1
VCB = open
47.5
50
52.5
VCB = VS
61.1
65
68.9
mV
1.3 x
VCB_TH
mV
3x
VCB_TH
mV
VCSP - VCSN = 300mV, CGATE = 10nF
(Note 3)
160
ns
VEN high to VGATE low
20
40
VON low to VGATE low
10
20
VON = step 0.8V to 2V
10
20
2.9V < VIN_< 18V
VGATE - VOUT = 0V
6
11
-13
-10
µs
µs
V
-7
µA
Maxim Integrated │ 3
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Electrical Characteristics (continued)
(VIN1 = VIN2 = 12V, CIN1 = CIN2 = CVS = 1µF, TA = -40°C to +125°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
GATE Pulldown Current
(Timeout)
IGATE_OFF
GATE Fast Pulldown Current
IGATE_FAST_
OFF
CONDITIONS
MIN
TYP
MAX
UNITS
VOUT = 12V, VGATE = VOUT + 5V
350
500
650
µA
VOUT = 12V, VGATE = VOUT + 5V
75
200
260
mA
(VCSP - VCSN) = 12V
3
6.7
10.7
%
VCB_TH
HOT-SWAP FOLDBACK
Minimum CB Voltage
VCB_FBMAX
Minimum Foldback Voltage
VFBMIN
VCSP - VOUT, at VCB = VCB_FBMAX
1
2.1
3.2
V
Maximum Foldback Voltage
VFBMAX
VCSP - VOUT, at VCB = VCB_TH
9
10
11
V
0.5
1.0
mA
CURRENT-SENSING INPUT
CSP Input Current
ICSP
VCSP = 12V
CSN Input Current
ICSN
VCSN = 12V
100
200
400
µA
CDLY Upper Threshold
VCDLY_U
VCDLY rising
1.1
1.2
1.3
V
CDLY Lower Threshold
Hysteresis
VCDLY_L
VCDLY falling
CDLY
CDLY Pullup Current
0.2
V
ICDLY_UP
-135
-100
-65
µA
CDLY Pulldown Current
ICDLY_DOWN
1.1
2
2.8
µA
CDLY Ratio
ICDLY_DOWN/
ICDLY_UP
1.2
2
3.2
%
POWER-GOOD (PG)
PG Threshold OUT
VPG_OUT
VGATE > (5V + VOUT)
PG Threshold GATE
VPG_GATE
VGATE - VOUT
PG Detection Timeout
PG Assertion Delay
0.9 x VCSP
V
4.2
V
tPG_STARTUP
55
70
85
ms
tPG_DELAY
13
16
19
ms
0.4
V
OUTPUTS (FAULT, PG)
FAULT, PG Output Voltage Low
VOL
IPG = IFAULT = 1mA
FAULT, PG Output Voltage High
VOH
IPG = IFAULT = 1µA
FAULT, PG Leakage Current
IOH
VPG = VFAULT = 18V
-1
FAULT, PG Pullup Current
IPU
VPG = VFAULT = 1.5V
-13
www.maximintegrated.com
VS - 1
VS - 0.6
-10
V
+20
µA
-7
µA
Maxim Integrated │ 4
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Electrical Characteristics (continued)
(VIN1 = VIN2 = 12V, CIN1 = CIN2 = CVS = 1µF, TA = -40°C to +125°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
ON, PC, EN Turn-On Threshold
VON_TH
ON, PC, EN Turn-On Threshold
Hysteresis
VON_HYS
CONDITIONS
MIN
TYP
MAX
UNITS
VON, VPC, VEN rising
1.1
1.22
1.32
V
VON, VPC, VEN falling hysteresis
70
123
180
mV
VON falling
0.5
0.6
0.7
V
VON, VPC = 0 to 2.5V
-1
+1
µA
INPUTS
ON Fault Reset Threshold
Voltage
ON, PC Input Leakage Current
VON_RESET
ILEAK
ON, PC Clamp Voltage
ISINK = 1µA
ON, PC Clamp Sink
VON, VPC = 5V
EN Pullup Current
IPU
VEN = 0V
-13
-75
3
V
300
µA
-10
-7
µA
CB THREE-STATE INPUT
CB Input Low Current
IIN_LOW
VCB = 0.4V
CB Input High Current
IIN_HIGH
VCB = VS - 0.2V
CB Input Open-Current Voltage
VCB_OPEN
Force ±4µA into unconnected CB pin; then
measure voltage on the CB pin
1.0
0.4
CB Low Voltage
VIL
VCB rising
CB High Voltage
VIH
VCB falling, relative to VS
µA
+75
µA
VS - 1
V
V
VS - 0.2
CURRENT MONITORING
Current Monitor vs.
Undervoltage Lockout
IPMON Offset (Note 2)
VIPMON_UVLO
VIPMON_O
VS rising
Hysteresis
VCSP = 12V
VCSP = 4.8V
to 18V
VCSP = 12V
IPMON Gain (Note 2)
GIM
VCSP = 4.8V
to 18V
www.maximintegrated.com
4.1
4.16
4.23
0.1
TA = +25°C
-80
+80
TA = 0°C to +85°C
-200
+200
TA = -40°C to +125°C
-240
+240
TA = -40°C to +125°C
-300
+300
TA = +25°C
71.315
71.565
71.815
71.136
71.565
71.994
TA = -40°C to +125°C
70.992
71.565
72.138
TA = -40°C to +125°C
70.992
71.565
72.138
TA = 0°C to +85°C
V
µV
V/V
Maxim Integrated │ 5
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Electrical Characteristics (continued)
(VIN1 = VIN2 = 12V, CIN1 = CIN2 = CVS = 1µF, TA = -40°C to +125°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Current Monitoring Total
Accuracy (Note 3)
SYMBOL
VIPMON_
ACCURACY
CONDITIONS
MIN
TYP
MAX
VCSP = 12V, RSENSE = 3mΩ, ILOAD = 1A,
(VCSP - VCSN) = 3mV, TA = +25°C,
VIPMON_ACCURACY = ((VIPMON 214.7mV)/214.7mV) x 100
-3
+3
VCSP = 12V, RSENSE = 3mΩ, ILOAD = 3A,
(VCSP - VCSN) = 9mV, TA = +25°C,
VIPMON_ACCURACY = ((VIPMON 644.085mV)/644.085mV) x 100
-1
+1
VCSP =12V,RSENSE = 3mΩ, ILOAD =
5A, (VCSP - VCSN) = 15mV, TA = +25°C,
VIPMON_ACCURACY = ((VIPMON -1.073V)
/1.073V) x 100
-0.65
+0.65
VCSP = 12V, RSENSE = 3mΩ, ILOAD = 8A,
(VCSP - VCSN) = 24mV, TA = +25°C,
VIPMON_ACCURACY = ((VIPMON 1.7175V)/1.7175V) x 100
-0.5
+0.5
UNITS
%
CMRR (Note 4)
IPMON_CMRR
VCSP = 4.8V to 18V
102
dB
Output Voltage Range
VIPMONMAX
VCSP = 4.8V to 18V, -40°C ≤ TA ≤ +125°C
1.72
V
VIPMON_CLMP
VCSP - VCSN ≥ 36mV, VCSP = 4.8V to 18V,
-40°C ≤ TA ≤ +125°C
2.1
IPMON Voltage Clamp
2.3
2.5
V
Note 1: All devices are 100% production tested at TA = +25°C. Limits over temperature are guaranteed by design.
Note 2: Gain and offset are defined as VIPMON1 = VIPMON with Vi1 = (VCSP - VCSN) = 3mV, VIPMON2 = VIPMON with Vi2 =
(VCSP - VCSN) = 24mV, GIM = (VIPMON2 - VIPMON1)/(Vi2 - Vi1), VIPMON_OS = VIPMON1 - GIM x Vi1.
Note 3: Accuracy over the entire operating range can be determined combining the specified value of the related offset and gain in
the range.
Note 4: CMRR is calculated as:
VREF = VIPMON with VCSP - VCSN = 3mV at VREF = VCSP = 12V,
VCM = VIPMON with VCSP - VCSN = 3mV at 4.8V < VCSP < 18V,
CMRR = 20 x LOG(ABS((12 - VCSP)/(VREF - VCM)) x GIM),
where GIM is the differential gain defined in the Electrical Characteristics table.
www.maximintegrated.com
Maxim Integrated │ 6
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Typical Operating Characteristics
(VIN1 = VIN2 = 12V, CIN1 = CIN2 = CVS = 1µF, RSENSE = 3mΩ, unless otherwise noted.)
IN_ SUPPLY CURRENT vs. VOLTAGE
ORing GATE DRIVE vs. CURRENT
VS LOAD REGULATION
toc01
6
toc02
6
toc03
12
VIN_ = 12V or 18V
10
5
IIN2
VIN_ = 5V
VS (V)
IIN_ (mA)
4
VIN_ = 3.7V
3
IIN1
2
VOG_ - VIN_ (V)
4
VIN_ = 2.9V
2
3
6
9
VIN_ (V)
12
15
0
18
0
4
6
8
0
10
0
VOG_ - VIN_ (V)
10
8
6
0
11
14
8
VIN_ = 3.7V
6
VIN_ = 2.9V
20
40
60
80
100
120
VIN_ = 3.7V
6
VIN_ = 2.9V
5
CB = Hi-Z
CB = GND
40
20
10
35
60
TEMPERATURE (ºC)
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85
110 125
15
ACTIVE CURRENT-LIMIT SENSE VOLTAGE
vs. TEMPERATURE
ACTIVE CURRENT-LIMIT SENSE VOLTAGE (mV)
60
10
IGATE (µA)
toc07
CB = VS
CIRCUIT-BREAKER TRIP VOLTAGE (mV)
VIN_ = 5V
9
0
140
CIRCUIT-BREAKER TRIP VOLTAGE
vs. TEMPERATURE
-15
VIN_ = 12V or 18V
IIOG_ (µA)
80
140
0
0
VIN_ (V)
120
3
0
17
100
12
VIN_ = 18V
2
2
80
toc06
VOUT = VIN_
4
4
-40
60
15
VIN_ = 12V
10
8
40
HOT-SWAP MOSFET GATE VOLTAGE
vs. CURRENT
toc05
12
12
5
20
IICP_ (µA)
ORing GATE VOLTAGE vs. CURRENT
toc04
14
VOG_- VIN_ (V)
2
ILOAD (mA)
ORing GATE DRIVE vs. INPUT VOLTAGE
2
VIN_ = 2.9V
2
VGATE - VOUT (V)
0
VIN_ = 3.7V
6
4
1
0
VIN_ = 12V
VIN_ = 18V
8
toc08
100
CB = VS
80
CB = Hi-Z
60
CB = GND
40
-40
-15
10
35
60
85
110 125
TEMPERATURE (ºC)
Maxim Integrated │ 7
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Typical Operating Characteristics (continued)
(VIN1 = VIN2 = 12V, CIN1 = CIN2 = CVS = 1µF, RSENSE = 3mΩ, unless otherwise noted.)
CB = Hi-Z
CB = VS
1
0.1
CB = GND
50
100
150
200
250
30
20
10
toc12
20
2
4
6
CURRENT (mA)
8
IPMON OUTPUT ACCURACY (%)
GATE PULLUP CURRENT (µA)
10
5
0
10
35
60
85
10
35
VIN_ = 18V
-10
-15
2
4
6
8
10
-5
VIN_ = 12V
-15
0
2
4
5
IPMON OUTPUT ACCURACY (%)
VIN_ = 18V
6
8
IPMON OUTPUT ACCURACY
(TA = +125ºC)
10
12
toc16
VIN_ = 12V or 18V
VIN_ = 4.5V
-15
VIN_ = 4.5V
VIN_ = 18V
-10
CURRENT (A)
toc15
VIN_ = 4.5V
toc14
0
12
VIN_ = 12V or 18V
-10
110 125
-20
0
VIN_ = 12V
85
VIN_ = 12V or 18V
VIN_ = 4.5V
VIN_ = 4.5V
0
60
IPMON OUTPUT ACCURACY
(TA = +25ºC)
5
VIN_ = 18V
-5
-15
CURRENT (A)
VIN_ = 4.5V
IPMON OUTPUT ACCURACY (%)
toc13
-20
110 125
IPMON OUTPUT ACCURACY
(TA = +85ºC)
-5
-40
VIN_ = 12V
VIN_ = 12V
0
TEMPERATURE (ºC)
5
60
10
IPMON OUTPUT ACCURACY
(TA = -40ºC)
5
15
-15
80
TEMPERATURE (ºC)
VIN_ = 4.5V
-40
100
40
0
SENSE VOLTAGE (VCSP - VCSN) (mV)
GATE PULLUP CURRENT
vs. TEMPERATURE
120
0
300
toc11
140
40
0.01
0
CDLY PULLUP CURRENT
vs. TEMPERATURE
toc10
50
CDLY PULLUP CURRENT (µA)
10
toc09
OUTPUT LOW VOLTAGE (mV)
ACTIVE CURRENT-LIMIT DELAY (µs)
100
PG, FAULT OUTPUT LOW VOLTAGE
vs. CURRENT
IPMON OUTPUT ACCURACY (%)
ACTIVE CURRENT-LIMIT DELAY
vs. SENSE VOLTAGE
0
VIN_ = 18V
-5
VIN_ = 4.5V
-10
VIN_ = 12V
-15
-20
-20
0
2
4
6
CURRENT (A)
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8
10
12
0
2
4
6
8
10
12
CURRENT (A)
Maxim Integrated │ 8
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Typical Operating Characteristics (continued)
(VIN1 = VIN2 = 12V, CIN1 = CIN2 = CVS = 1µF, RSENSE = 3mΩ, unless otherwise noted.)
STARTUP WAVEFORM
(VIN = 2.9V)
STARTUP WAVEFORM
(VIN = 12V)
toc17
toc19
5V/div
2V/div
10V/div
VIN1
VIN1
STARTUP WAVEFORM
(VIN = 18V)
toc18
5V/div
VIN1
10V/div
VOG1
10V/div
5V/div
VOG1
5V/div
10V/div
VOG1
VGATE
VGATE
VGATE
40ms/div
40ms/div
OVERCURRENT-FAULT WAVEFORM
(CB = GND)
OVERCURRENT-FAULT WAVEFORM
(CB = Hi-Z)
toc21
toc20
10V/div
VIN1
40ms/div
OVERCURRENT-FAULT WAVEFORM
(CB = VS)
toc22
10V/div
VIN1
20V/div
VGATE
20V/div
VGATE
VOUT
10V/div
VOUT
10V/div
IOUT
20A/div
IOUT
20A/div
10V/div
VIN1
20V/div
VGATE
10V/div
VOUT
20A/div
IOUT
200µs/div
200µs/div
OUT SHORT-CIRCUIT RESPONSE
200µs/div
AUTORETY WAVEFORM
toc23
toc24
10V/div
VIN1
10V/div
VIN1
VGATE
20V/div
VOUT
10V/div
20V/div
VGATE
10V/div
VOUT
10A/div
IIN1
40µs/div
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20A/div
IOUT
200ms/div
Maxim Integrated │ 9
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Pin Configuration
OG1
CP1
GATE
OUT
TOP VIEW
20
19
18
17
+
CSN
1
16 CB
CSP
2
IN1
3
14 EN
VS
4
13 CDLY
GND
5
12 PC
IN2
6
11 FAULT
15 ON
MAX15068
7
8
9
10
OG2
CP2
IPMON
PG
EP
TQFN
(4mm × 5mm)
Pin Description
PIN
NAME
FUNCTION
1
CSN
Input Current Sense Negative Input
2
CSP
Input Current Sense Positive Input
3
IN1
Positive Supply 1 Input and MOSFET Gate Drive Return
4
VS
Internal Regulator Output. Bypass VS to GND with a 1μF capacitor.
5
GND
6
IN2
Positive Supply 2 Input and MOSFET Gate Drive Return
7
OG2
ORing MOSFET 2 Gate Control Output. Connect this pin to the gate of an external n-channel
MOSFET for ideal diode control. The gate voltage is limited to approximately 11V above and a diode
voltage below IN2. During fast turn-on, a 1A pullup switch charges OG2 from CP2. During fast turnoff, a 3A pulldown switch discharges OG2 to IN2.
8
CP2
Charge Pump 2 Output. Connect a capacitor from CP2 to IN2 pin. The value of this capacitor should
be approximately 10x the gate capacitance (CISS) of the external MOSFET for ORing diode control.
The charge stored on this capacitor is used to pull up the gate during a fast turn-on.
9
IPMON
Analog Current Monitor Output Signal. Connect a 560pF/6.3V ceramic capacitor from IPMON to GND.
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Maxim Integrated │ 10
Ground
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Pin Description (continued)
PIN
NAME
FUNCTION
10
PG
Power Status Output. Open-drain output that is normally pulled high by a 10µA current source to
a diode below VS. PG can be pulled above VS using an external pullup. PG pulls low when the
MOSFET gate drive between GATE and OUT exceeds the gate-to-source voltage of 4.2V and VOUT
is greater than 90% of VCSP. Leave PG unconnected if unused.
11
FAULT
Fault Status Output. Open-drain output that is normally pulled high by a 10µA current source to a
diode below VS. FAULT can be pulled above VS using an external pullup. FAULT pulls low when the
circuit breaker is tripped after an overcurrent fault timeout. Leave FAULT unconnected if unused.
12
PC
Priority Control Input. When low, it enables the external ideal diode MOSFET in the IN2 supply path
and a high turns it off. Connect PC to an external resistive divider from IN1 to make IN1 the higher
priority input supply when IN1 and IN2 are equal. Connect PC to GND if not used.
13
CDLY
Timer Capacitor Terminal. Connect a capacitor between CDLY and GND to set 12ms/µF duration
for current limit before the external hot-swap MOSFET is turned off. The duration of the off-time is
600ms/µF, resulting in a 2% duty cycle.
EN
Enable Input. Connect EN to GND to enable hot-swap control. If EN is pulled high, the hot-swap
MOSFET is not allowed to turn on. A 10µA current source pulls up EN to a diode below VS. Upon
EN going low when ON is high, an internal timer provides a 100ms startup delay for debounce, after
which the fault is cleared.
15
ON
On Control Input. When above 1.2V, it turns on the external hot-swap MOSFET and when below
1.1V, it turns it off. Connect ON to an external resistive divider from CSP to monitor the supply
undervoltage condition. Pulling voltage of ON pin below 0.6V resets the electronic circuit
breaker.
16
CB
Current-Limit Threshold Setting. Connect the CB pin to VS, GND, or leave CB unconnected to set
the circuit-breaker threshold. See Table 1 for details.
17
OUT
Load Output. Connect OUT to the source of the external hot-swap MOSFET.
18
GATE
Hot-Swap MOSFET Gate Drive Output. Connect this pin to the gate of the external n-channel
MOSFET for hot-swap control. An internal 10µA current source charges the MOSFET gate. An
internal clamp limits the gate voltage to 11V above OUT and a diode voltage below OUT. During
turn-off, a 500µA pulldown current discharges GATE to ground. During an output short to ground, a
fast 200mA pulldown current discharges GATE to OUT.
19
CP1
Charge Pump 1 Output. Connect a capacitor from CP1 to IN1 pin. The value of this capacitor should
be 10x or greater than the gate capacitance of the external MOSFET for ideal diode control. The
charge stored on this capacitor is used to pull up the gate during a fast turn-on.
20
OG1
ORing MOSFET 1 Gate Control Output. Connect OG1 to the gate of an external n-channel MOSFET
for ideal diode control. The gate voltage is set to approximately 11V above and a diode voltage
below IN1. During fast turn-on, a 1A pullup switch charges OG1 from CP1. During fast turn-off, a 3A
pulldown switch discharges OG1 to IN1.
—
EP
Exposed Pad. Connect EP to the ground plane to provide a low thermal resistance path from the IC
junction to the PCB. Do not use EP as the only electrical connection to GND.
14
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Maxim Integrated │ 11
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Functional Diagram
IN1
MAX15068
CSP
CSN
IN2
VCB
IPMON
MAX15068 - CURRENT MONI TOR
-
+
1.3 x VCB
GATE
+
+
-
GATE
DRIVER
OUT
10µA
VS
CP1
CHARGE
PUMP 3
VS
CHARGE
PUMP 2
VS
+
10mV
10mV
1.2V
VS
OG2
+
+
+
-
-
OG1
CP2
CHARGE
PUMP 1
VS
REFERENCE
GENERATOR
VS
LDO
REGULATOR
UV2
10µA
GATE
10µA
10µA
2.49V
PG
GATE_OK
UV1
0.9 x VCSP
2.65V
CIRCUIT BREAKER
1.2V
FAULT
OVERCURRENT
GATE ON
LOGIC CONTROL
ON
EN
CARD PRE SENT
FAULT RESET
1.2V
+0.6V
PC
VS
100µA
1.2V
1.2V
CB
VCB
CDLY
+
2µA
-
65mV
+
-
50mV
+
-
35mV
+0.2V
GND
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Maxim Integrated │ 12
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Detailed Description
Startup
When input voltage is applied to IN_, CSP comes up to
one diode below the higher of IN1 or IN2. The internal
LDO regulator powers VS from the higher of two inputs as
well. When both VS and CSP reach their respective UVLO
thresholds, the internal charge pumps (CP1 or CP2)
for the ORing controller start operating. An internal time
starts when both ON is above its threshold and EN is
below its threshold. After the timer counts 85ms, the
ORing control (OG1 or OG2) begins operating. After
another 15ms have elapsed, the hot-swap control (GATE)
also starts operating.
ORing Control
ORing Control in Startup
As soon as the internally generated supply, VS, rises
above its undervoltage lockout threshold, the internal
charge pump is allowed to charge up the CP_ pins.
Because the ideal diode MOSFETs are connected in
parallel as a diode-OR, the CSP pin voltage selects the
highest of the supplies at the IN1 and IN2 pins. The
MOSFET associated with the lower input supply voltage is
turned off by the corresponding gate drive amplifier.
At power-up the CP_ and OG_ pin voltages are at the IN_
voltage level. CP_ starts ramping up after VS clears its
undervoltage lockout level.
If the amplifier senses a forward voltage drop greater than
80mV between IN and CSP then the OG_ pin is pulled to
CP_ to quickly turn on the MOSFET. If the amplifier senses
a reverse voltage drop greater than 10mV between CSP
and IN_, then the OG_pin is pulled to IN_ to quickly turn
off the MOSFET. With the ideal diode MOSFETs acting as
an input supply diode-OR, the CSP pin voltage rises to the
highest of the supplies at the IN1 and IN2 pins. The stored
charge in an external capacitor connected between the
CP_ and IN_ pins provides the charge needed to quickly
turn on and off the ideal diode MOSFET. An internal charge
pump charges the external capacitors at the CP_ pins.
The OG_ pin sources current from the CP_ pin and sinks
current into the IN_ and GND pins.
ORing MOSFET Regulation Mode
When the ideal diode MOSFET is turned on, the gate
drive amplifier controls OG_ to servo the forward voltage
drop (VIN - VCSP) across the MOSFET to 10mV. If the
load current causes more than 10mV of voltage drop,
across the FET, then the OG_ voltage rises to 11V (typ)
above IN_ to fully enhance the MOSFET. For large output
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currents, the MOSFET’s gate is driven fully on and the
voltage drop is equal to ILOAD x RDS(ON) of the MOSFET.
Hot-Swap Control
Hot-Swap in Startup
Once the output is enabled, the device provides
controlled application of power to the load.
An external capacitor connected to the GATE pin allows
the user to program the slew rate to a value lower than the
default. During startup, a foldback current limit is active to
protect the external hot-swap MOSFET to operate within
the SOA (Figure 1).
An internal timer is activated to count for 70ms, which is
the maximum time duration for the startup phase. The
startup phase is completed when the voltage at OUT rises
above the power-good threshold (0.9 x VCSP typical)
and hot-swap GATE to OUT voltage exceeds 4.2V even
though the 70ms timeout has not yet elapsed. Once the
power-good threshold is achieved, the normalized circuitbreaker threshold goes to its full value.
Programmable Speed Circuit-Breaker Response
on Hot-Swap MOSFET
The device features an adjustable current limit with
circuit-breaker function that protects the external
MOSFETs against short circuits or excessive load current.
The voltage across the external sense resistor (RSENSE)
is monitored by an electronic circuit breaker and active
current limit amplifier (ACL). The electronic circuit breaker
turns off the hot-swap MOSFET with a 500µA current
from GATE to OUT if the voltage across the sense resistor exceeds VCB_TH for longer than the fault filter delay
configured at the CDLY pin. Active current limiting begins
when the sense voltage exceeds the ACL threshold VACL
(ACL) (which is 1.3x VCB_TH). The gate of the hot-swap
MOSFET is brought under control by the ACL amplifier
and the output current is regulated to maintain the ACL
VCB NORMALIZE
Figure
1
THRESHOLD
0.6
0.5
0.4
0.3
0.2
0.1
VCSN - VOUT
2V
10V
12V
Figure 1. Inrush Current vs. Voltage Drop Across the Hot-Swap
Switch During Startup Period
Maxim Integrated │ 13
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
threshold across the sense resistor. At this point, the fault
filter starts the timeout with a 100µA current charging the
CDLY pin capacitor. If the CDLY pin voltage exceeds its
threshold (1.2V), the external MOSFET is turned off and
the FAULT pin pulls low.
After the hot-swap MOSFET turns off, the CDLY pin
capacitor is discharged with a 2µA pulldown current until
it reaches 0.2V. This is followed by a cool-off period of 14
timing cycles at the CDLY pin. At the end of the cool-off
period and the GATE pin restarts charging up the gate of
the MOSFET.
In the event of a severe short-circuit fault on the 12V
output, the output current can surge very high. The
device responds within 1µs to bring the current under
control by pulling the GATE to OUT voltage down with a
200mA current. Almost immediately, the gate of the hotswap MOSFET recovers rapidly due to the RGATE and
CGATE network, and load current is actively limited until
the electronic circuit breaker times out. Due to parasitic
supply lead inductance, an input supply without any bypass
capacitor may collapse during the high current surge and
then spike upwards when the current is interrupted.
Programmable Circuit-Breaker Current Threshold
The device features a programmable current limit with
circuit-breaker function that protects the external
MOSFETs against short circuits or excessive load current.
The voltage across the external sense resistor, (RSENSE)
is monitored by an electronic circuit breaker and active
current limit (ACL) amplifier. Connect the CB pin to GND,
VS, or leave unconnected to select the circuit-breaker
threshold (Table 1).
Timer (CDLY)
An external capacitor connected from the CDLY pin to
GND serves as fault filtering when the supply output is in
active current limit. When the voltage across the sense
resistor exceeds the circuit-breaker trip threshold, CDLY
pulls up with 100µA. Otherwise, it pulls down with 2µA.
The fault filter times out when the 1.2V CDLY threshold
is exceeded, causing the FAULT pin to pull low. The fault
filter delay or circuit-breaker time delay is:
tCB = CCDLY x 12[ms/µF]
After the circuit-breaker timeout, the CDLY pin capacitor
pulls down with 2µA from the 1.2V CDLY threshold until
it reaches 0.2V. Then it completes 14 cooling cycles
consisting of the CDLY pin capacitor charging to 1.2V
with a 100µA current and discharging to 0.2V with a 2µA
current. At that point, the GATE pin voltage is allowed to
www.maximintegrated.com
start up and the FAULT pin pulls high. The total cool-off
time for the MOSFET after an overcurrent fault is:
tCOOL = CCDLY x 7.13[s/µF]
ORing Response in Overload Condition
During the fault condition, the ORing MOSFET remains on.
Control Inputs
ON Input
The device drives the OG_ as soon as the VIN1 - VF1
(VF1 is the forward voltage drop of ORing MOSFET
connected to IN1) or VIN2 - VF2 (VF2 is the forward
voltage drop of the ORing MOSFET connected to IN2)
supply voltage generates a VON above the threshold
voltage. An external resistive divider from CSP to ON
and ground is used to set the turn-on voltage to any
desired voltage from 2.9V to 5.5V. The IC turns on the
corresponding ORing MOSFET and then turns on the hotswap MOSFET when VON > 1.22V.
The device turns off the output when VON falls below
VUV_REF (1.22V - VON_HYS). An external resistive
divider from CSP to ON and ground is used to set
the undervoltage-lockout threshold to any desired level
between VUVLO and 18V.
Monitoring
Analog Current Monitor Output
IPMON monitors the system input current and provides the
best accuracy when VIPMON is less than 1.7V, or VSENSE
is less than 23.75mV. The IPMON signal is clamped at
2.3V, or VSENSE = 32mv. For best performance, add a
560pF/6.3V ceramic capacitor between IPMON and GND.
The voltage at IPMON (VIPMON) is proportional to the
input current (ISYS) given by the following equation:
VIPMON = GIM x ISYS x RSENSE
where GIM = 71.565, a fixed voltage gain.
Adding a resistive voltage divider at the IPMON output
(Figure 2) allows the overall VIPMON gain (G) to be
adjusted per the following equation:
G = GIM x R2/(R1+R2)
where R1 = 20kΩ, C1 = 560pF, and C2 = 1nF. The
resistive-divider equivalent resistance R1||R2 needs to be
carefully selected, as it affects accuracy due to the input
bias current of the system readout.
Maxim Integrated │ 14
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Output Signals
Fault Status Output (FAULT)
FAULT is an open-drain output that is internally pulled high
by a 10µA current source to a diode below VS, and can be
pulled above VS using an external pullup. FAULT asserts
low when the circuit breaker is tripped after an overcurrent
fault timeout. Leave FAULT unconnected if unused.
Power-Good Output (PG)
Internal circuitry monitors the hot-swap MOSFET gate
overdrive between the GATE and OUT pins and the voltage
at the OUT pin. The power-good status for the supply is
reported by the PG open-drain output. It is pulled high by
an external pullup resistor or the internal 10µA pullup. The
power-good output asserts low when the gate overdrive
exceeds 4.2V during the GATE startup and the voltage
at the OUT pin exceeds (0.9 x VCSP). The PG signal is
delayed by 16ms once conditions for power-good are met.
Fault Management
Autoretry
When an overcurrent fault is latched after tripping the
circuit breaker, the FAULT pin is asserted low. Only the
hot-swap MOSFET is turned off, and the ideal diode
MOSFETs are not affected. The latched fault is reset
automatically after a cool-off timing cycle as described
in the Timer (CDLY) section. At the end of the cool-off
Figure 2
period, the fault latch is cleared and FAULT pulls high.
The GATE pin voltage is allowed to start up and turn on
the hot-swap MOSFET. If the output short persists, the
supply powers up into a short with active current limiting
until the circuit breaker times out and FAULT again pulls
low. A new cool-off cycle begins with CDLY ramping down
with a 2µA current. The whole process repeats itself until
the output short is removed. Since tCB and tCOOL are a
function of CDLY capacitance, CCDLY, the autoretry duty
cycle is equal to 0.1%, irrespective of CCDLY.
Applications Information
Prioritizing Supplies with PC
Figure 2 shows an ORing application where a resistive
divider connected from IN1 at the PC pin controls the turnon of the ORing MOSFET, MD2, in the IN2 supply path.
When the IN1 supply voltage falls below 4.5V, it turns
on the ORing MOSFET, MD2, causing the ORing output
to be switched from the main 5.0V supply at IN1 to the
auxiliary 5.0V supply at IN2. This configuration permits the
load to be supplied from a lower IN1 supply as compared
to IN2 until IN1 falls below the MD2 turn-on threshold. The
threshold value used should not allow the IN1 supply to
be operated at more than one diode voltage below IN2.
Otherwise, MD2 conducts through the MOSFET’s body
diode. The resistive divider connected from CSP at the
ON pin provides the undervoltage threshold of 2.6V for
the ORing output supply.
R1
VIPMON
TO SYSTEM
C1
R2
C2
Figure 2. External RC Network to Adjust VIPMON
Table 1. Circuit-Breaker Threshold Programming
CB PIN CONNECTION
CIRCUIT-BREAKER THRESHOLD (VCSP - VCSN) [mV]
CB = GND
35
CB = Hi-Z (unconnected)
50
CB = VS
65
www.maximintegrated.com
Maxim Integrated │ 15
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Figure 3
MD1
5V
0.003Ω
MD2
5V
5V
RSE NS E
120kΩ
CP1
IN1
OG1
CP2
IN2
OG2
CSP
CSN
ON
GATE
OUT
FAULT
20kΩ
PG
MAX15068
IPMON
EN
PC
VS
CB
GND
CDLY
69.8kΩ
20kΩ
Figure 3. Plug-in Card IN1 Supply Controls the IN2 Supply Turn-On Through the PC Pin
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Maxim Integrated │ 16
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Typical Application Circuit
12V
0.003Ω
12V
12V
RSE NS E
CP1
137kΩ
IN1
OG1
CP2
IN2
OG2
CSP
CSN
ON
GATE
OUT
FAULT
20kΩ
PG
MAX15068
IPMON
EN
VS
CB
GND
PC
CDLY
Ordering Information
PART
MAX15068ATP+
OPERATING RANGE
FUNCTION
TEMP RANGE
PIN-PACKAGE
2.9V to 18V
Autoretry, Current Monitor
-40°C to +125°C
20 TQFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Chip Information
PROCESS: BiCMOS
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Maxim Integrated │ 17
MAX15068
Dual ORing, Single Hot-Swap Controller with
Accurate Current Monitoring
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
0
12/13
1
2/16
2
5/18
Updated the Package Information table.
3
10/19
Corrected errors, eliminated redundant descriptions, and clarified descriptions.
Removed overbar on PC pin name to match functionality.
DESCRIPTION
Initial release
Customer test spec changes: Updated General Description, Benefits and
Features, Electrical Characteristics table; replaced TOC2–TOC6, TOC17,
and changed TOC13–TOC16 titles in Typical Operating Characteristics
section; updated IPMON pin 9 function in Pin Description table; updated
2nd equation in Timer (CDLY) section; replaced Analog Current Monitor
Output section, adding a new Figure 2; renumbered and replaced new
Figure 3 and replaced Typical Application Circuit; updated operating range
in Ordering Information table
—
1–9, 13–16
2
1–17
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
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 and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2019 Maxim Integrated Products, Inc. │ 18
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