General Description
The MAX5913/MAX5914 are quadruple hot-swap con-
trollers. The MAX5913/MAX5914 independently control
four external N-channel switches to hot-swap system
loads from a single VCC supply line. The devices allow
the safe insertion and removal of power devices from
live network ports. Operating supply voltage range is
between +35V and +72V. The devices are intended for
applications in Power-Over-Media-Dependent Interface
(MDI), but are not limited to such usage.
The MAX5913/MAX5914 feature an internal undervolt-
age lockout (UVLO) function that prevents the FET from
turning on, if VCC does not exceed the default value of
+32V. The devices also feature a +12V relay driver with
100mA current drive capable of driving low-voltage
+3.3V relays. The MAX5913 features an active-low relay
driver that sinks current when the relay output is
enabled. The MAX5914 features an active-high relay
driver output that sources 1mA to drive an external FET
relay driver when the relay output is enabled. Control
circuitry ensures the relays and the FETs are off until
VCC reaches the UVLO threshold. The MAX5913/
MAX5914 use an external sense resistor to enable all
the internal current-sense functions.
The MAX5913/MAX5914 feature a programmable ana-
log current-limit circuit. If the switch remains in current
limit for more than a programmable time, the N-channel
FET latches off and the supply can be restarted either
by autoretry or by an external command after the preset
off-time has elapsed.
The MAX5913/MAX5914 are available in a 44-pin MQFP
package and are specified for the extended -40°C to
+85°C operating temperature range.
Applications
Power-Over-LAN
Power-Over-MDI
IP Phone Switches/Routers
Telecom Line Cards
Network Switches/Routers
Mid-Span Power-Over-MDI
Features
♦Wide Operating Input Voltage Range
+35V to +72V
♦IEEE 802.3AF Compatible
♦Four Independent Power Switch Controllers
♦Open-Circuit Detector
♦On-Board Charge Pumps to Drive External
N-Channel FETs
♦Current Sense with External Resistor
♦Foldback Current Limiting
♦+32V Input Undervoltage Lockout
♦On-Chip +12V, 100mA Voltage Relay Drivers
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
________________________________________________________________ Maxim Integrated Products 1
RTRYEN
STATOUT
OCEN
DGND
VCC
CSP1
DRAIN1
GATE1
OUT1
CSP2
DRAIN2
FAULT
STAT1
STAT2
STAT3
STAT4
CSP4
DRAIN4
OUT4
GATE4
CSP3
DRAIN3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
OUT3
GATE3
VRLY
RLYD3
RLYD4
DGND
RLYD1
RLYD2
AGND
OUT2
GATE2
VDD
RTIM
ON4
RLYON4
ON3
RLYON3
ON2
RLYON2
ON1
RLYON1
DC
MQFP
TOP VIEW
MAX5913
MAX5914
Pin Configuration
Ordering Information
19-2244; Rev 2; 11/02
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
PART TEMP RANGE PIN-PACKAGE
MAX5913EMH -40°C to +85°C 44 MQFP
MAX5914EMH -40°C to +85°C 44 MQFP
Typical Operating Circiut appears at end of data sheet.
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = VCSP_ = +48V, AGND = DGND = 0, VDD = +3.3V, VRLY = +12V, TA= -40°C to +85°C, unless otherwise noted. Typical values
are at VCC = VCSP_ = +48V and TA= +25°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.
VCC to AGND or DGND..........................................-0.6V to +76V
DRAIN_, OUT_ to AGND or DGND................-0.6V to VCC +0.3V
CSP_ to VCC ..........................................................-0.3V to +0.3V
GATE_ to OUT_ .....................................................-0.3V to +13V
VRLY to DGND ........................................................-0.3V to +18V
RLYD_ to DGND........................................-0.3V to (VRLY + 0.3V)
ON_, RLYON_, OCEN, RTRYEN, STATOUT,
DC to DGND........................................................-0.3V to +12V
FAULT to DGND .....................................................-0.3V to +12V
STAT_, RTIM to DGND ...............................-0.3V to (VDD + 0.3V)
VDD to DGND ...........................................................-0.3V to +7V
DGND to AGND...........................................................-5V to +5V
Current into RLYD_ .........................................-50mA to +150mA
Current into Any Other Pin................................................±50mA
Continuous Power Dissipation (TA= +70°C)
44-Pin MQFP (derate 12.7mW/°C above +70°C)......... 1.013W
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................ +300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER SUPPLIES
Analog Supply Voltage VCC Measured with respect to AGND 35 72 V
0°C to +85°C 2.7 4
Analog Supply Current ISVCC = VCSP_ = 72V
IS = ICC + ICSP -40°C to 0°C5
mA
Digital Supply Voltage VDD Measured with respect to DGND 1.8 3.3 3.7 V
Digital Supply Current IDD All logic outputs high, RTIM floating 1.1 3 mA
Analog Supply Undervoltage
Lockout VUVLO VCC rising, circuits enabled 29 32 35 V
UVLO Hysteresis VUVLO
,
H3V
UVLO Deglitch Delay tD
,
UVLO VON = 3.3V, VRLYON = 3.3V (Figure 1) 12.8 25.6 38.4 ms
Relay Driver Supply VRLY Measured with respect to DGND 14 V
Ground Potential Difference VGG Voltage difference between DGND and AGND -4 4 V
FEEDBACK INPUT AND CURRENT SENSE
OUT Sense Bias Current IFP VOUT_ = VCC 2µA
Initial Feedback Voltage VFB_S
Voltage under which the foldback circuit starts
reducing the current-limit value
(Note 1)
18 V
Current-Limit Threshold Voltage VSC Maximum ∆V across RSENSE at VOUT > VFB_S125 142.5 160 mV
Foldback Voltage VFLBK Maximum ∆V across RSENSE at VOUT = 0 42 48 54 mV
Fast Discharge Threshold VFC 360 420 480 mV
Switch-On Threshold VSWON Maximum VCC - VOUT at which the switch is
defined as fully on, VOUT increasing 1.2 1.5 1.8 V
Switch-On Comparator Hysteresis VSWON_H160 mV
MOSFET DRIVERS
VGATE - VCC when switch is fully on
0°C to +85°C7911
Gate Overdrive Voltage VGS
-40°C to 0°C7912
V
Gate Charge Current IGATE VGATE = 0 7 10 13 µA
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC = VCSP_ = +48V, AGND = DGND = 0, VDD = +3.3V, VRLY = +12V, TA= -40°C to +85°C, unless otherwise noted. Typical values
are at VCC = VCSP_ = +48V and TA= +25°C.) (Note 3)
Note 1: See Typical Operating Characteristics for Current-Limit Foldback, and refer to Current Sensing and Regulation section.
Note 2: The resistor at RTIM can range from 2kΩto 40kΩ.
Note 3: Limits are 100% tested at TA= +25°C and TA= +85°C. Limits at -40°C are guaranteed by design and characterization, but
are not production tested.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
During current regulation 8 µA
VON = 0 1 mA
Gate Discharge Current IGATE,DIS
(VCSP_ - VDRAIN_) > VFC 15 mA
Source-Gate Clamp Voltage VSGZ VOUT_ = 0, force 30mA into GATE_, measure
VGATE - VOUT 14 16.5 18 V
OPEN-CIRCUIT DETECTOR
Open-Circuit Current-Threshold
Voltage VOC Minimum ∆V across RSENSE to detect an
open circuit 1.5 3 4.5 mV
Delay to Open-Circuit Detect tOC (Figure 2) 450 900 1350 ms
Deglitch Delay tLPFD (VCSP_ - VDRAIN__) < VOC (Figure 2) 106 204 302 ms
RELAY DRIVERS
Maximum Low Voltage (MAX5913) VRLOW RLYON = high, IRLYD_ = 100mA 0.5 V
Relay Pullup Current (MAX5914) IRPLUP RLYON = high, VRLYD_ = 0 0.3 0.8 1.3 mA
Clamp Diode Voltage VRCLAMP Force 100mA into RLYD, measure VRLYD -
VRLY 2V
Relay Output Leakage RLYON_ = low, VRLYD_ = VRLY 1µA
TIMING
RRTIM = 2kΩ4.8 6.4 8.0
RRTIM = 40kΩ76 128 180
Short-Circuit and Startup Timer
(Note 2) tOOn time for continuous
overcurrent conditions
RRTIM = ∞3.2 6.4 9.6
ms
DC = logic low 1
DC = logic high 2
Auto-Retry Duty Cycle
DC = floating 4
%
Port Turn-ON Delay tON_DEL VON = 3.3V (Figure 3) 12.8 25.6 38.4 ms
Relay Turn-OFF Delay tOFF_DEL After RLYON_ goes low (Figure 3) 1.6 3.2 4.8 ms
DIGITAL INTERFACE
DC Pin Input Voltage High VIH_DC +1.8V ≤ VDD ≤ +3.7V 0.7 x VDD V
DC Pin Input Voltage Low VIL_DC +1.8V ≤ VDD ≤ +3.7V 0.3 x VDD V
DC Pin Input Impedance RIN_DC 1kΩ
Logic Input High VIH +1.8V ≤ VDD ≤ +3.7V 0.8 x VDD V
Logic Input Low VIL +1.8V ≤ VDD ≤ +3.7V 0.3 x VDD V
Logic Input Leakage 1µA
FAULT Output Voltage Low VFL ISINK = 4mA 0.4 V
FAULT High Input Leakage 1µA
Logic Output Voltage High VOH STAT_ outputs sourcing 0.5mA VDD - 0.4 mV
Logic Output Voltage Low VOL STAT_ outputs sinking 0.5mA 0.4 V
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA= +25°C, unless otherwise specified.)
2.0
2.4
3.2
2.8
3.6
4.0
33 45 48
39 4236 54 5751 60 63 66 69 72
SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX5913/4 toc01
INPUT VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +85°CTA = +25°C
TA = -40°C
3.8
3.4
3.0
2.6
2.2
3.5
3.4
3.3
3.2
3.1
3.0
2.9
2.8
2.7
2.6
2.5
-40 10-15 35 60 85
SUPPLY CURRENT
vs. TEMPERATURE
MAX5913/4 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
VCC = +36V
VCC = +48V
VCC = +57V
VCC = +72V
27
28
30
29
31
32
-40 10-15 35 60 85
UNDERVOLTAGE LOCKOUT
vs. TEMPERATURE
MAX5913/4 toc03
TEMPERATURE (°C)
UVLO (V)
VCC RISING
VCC FALLING
9.50
9.25
9.00
8.75
8.50
33 36 39 54 57 6042 45 48 51 63 6966 72
GATE OVERDRIVE VOLTAGE
vs. INPUT VOLTAGE
MAX5913/4 toc04
INPUT VOLTAGE (V)
GATE OVERDRIVE (V)
TA = -40°C
TA = +85°C
TA = +25°C
8.0
8.5
9.0
9.5
GATE OVERDRIVE VOLTAGE
vs. TEMPERATURE
MAX5913/4 toc05
TEMPERATURE (°C)
GATE OVERDRIVE (V)
-40 35 60-15 10 85
VCC = +57V VCC = +72V
VCC = +48V
VCC = +36V
STARTUP WAVEFORMS
MAX5913/4 toc06
0
A
B
C
D
0
0
0
4ms/div
A: VON = VRLYON, 5V/div
B: VRLYD, 20V/div
C: VOUT, 20V/div
D: VGATE, 20V/div
TURN-OFF WAVEFORMS
MAX5913/4 toc07
0A
B
C
D
0
0
0
4ms/div
A: VON = VRLYON, 5V/div
B: VRLYD, 20V/div
C: VOUT, 20V/div
D: VGATE, 20V/div
GATE TURN-OFF WAVEFORM
MAX5913/4 toc08
0A
B
0
C
0
D
0
10ms/div
A: VRLYD, 20V/div
B: VRLYON, 5V/div
C: VON, 5V/div
D: VGATE, 20V/div
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
_______________________________________________________________________________________ 5
TURN-ON INTO CAPACITIVE LOAD
(CL = 0.47µF)
MAX5913/4 toc10
0
A
B
0
C
0
D
0
400µs/div
RLYON = VDD
A: VON, 5V/div
B: VGATE, 20V/div
C: VOUT, 20V/div
D: IOUT, 100mA/div
TURN-ON INTO CAPACITIVE LOAD
(CL = 47µF)
MAX5913/4 toc11
0
A
B
0
C
0
D
0
1ms/div
RLYON = VDD, RRTIM = 2kΩ
A: VON, 5V/div
B: VGATE, 20V/div
C: VOUT, 20V/div
D: IOUT, 200mA/div
TURN-ON INTO CAPACITIVE LOAD
(CL = 470µF)
MAX5913/4 toc12
0
A
B
0
C
0
D
0
10ms/div
RLYON = VDD, RRTIM = 40kΩ
A: VON, 5V/div
B: VGATE, 20V/div
C: VOUT, 20V/div
D: IOUT, 200mA/div
CURRENT-LIMIT FOLDBACK
(VCC = +36V)
MAX5913/4 toc13
0
A
B
0
C
0
10ms/div
RLYON = VDD, RL = 100Ω, RRTIM = 40kΩ, CLOAD = 470µF
A: VON, 5V/div
B: VOUT, 10V/div
C: IOUT, 200mA/div
CURRENT-LIMIT FOLDBACK
(VCC = +48V)
MAX5913/4 toc14
0
A
B
0C
0
10ms/div
RLYON = VDD, RL = 139Ω, RRTIM = 40kΩ, CLOAD = 470µF
A: VON, 5V/div
B: VOUT, 10V/div
C: IOUT, 200mA/div
CURRENT-LIMIT FOLDBACK
(VCC = +57V)
MAX5913/4 toc15
0
A
B
0C
0
10ms/div
RLYON = VDD, RL = 162Ω, RRTIM = 40kΩ, CLOAD = 470µF
A: VON, 5V/div
B: VOUT, 10V/div
C: IOUT, 200mA/div
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA= +25°C, unless otherwise specified.)
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA= +25°C, unless otherwise specified.)
CURRENT-LIMIT FOLDBACK
(VCC = +72V)
MAX5913/4 toc16
0
A
B
0C
0
10ms/div
RLYON = VDD, RL = 200Ω, RRTIM = 40kΩ
A: VON, 5V/div
B: VOUT, 10V/div
C: IOUT, 200mA/div
CURRENT-LIMIT FOLDBACK
(VCC = +57V)
MAX5913/4 toc17
0
0
A
B
C
0
10ms/div
RLYON = VDD, RL = OPEN,
RRTIM = 40kΩ, CLOAD = 470µF
A: VON, 5V/div
B: VOUT, 10V/div
C. IOUT, 200mA/div
OVERCURRENT DELAY
(EXPANDED TIME SCALE)
MAX5913/4 toc20
0
A
B
0
1ms/div
RTRYEN = VDD, RLYON = ON = VDD,
DC = DON'T CARE, RRTIM = 2kΩ, RL = 100Ω
A: VGATE, 20V/div
B: IOUT, 200mA/div
OVERCURRENT DELAY
MAX5913/4 toc19
0
A
B
0
20ms/div
RTRYEN = VDD, RLYON = ON = VDD, DC = 4%,
RRTIM = 2kΩ, RL = 100Ω
A: VGATE, 20V/div
B: IOUT, 200mA/div
CURRENT-LIMIT FOLDBACK
(VCC = +72V)
MAX5913/4 toc18
0
A
C
0
20ms/div
RLYON = VDD, RL = OPEN, RRTIM = 40kΩ, CLOAD = 470µF
A: VON, 5V/div
B: VOUT, 20V/div
C: IOUT, 200mA/div
B
0
SHORT-CIRCUIT RESPONSE
(VCC = +48V)
MAX5913/4 toc21
0
A
B
0
1ms/div
ON = RLYON = VDD, RL = 1Ω, RRTIM = 2kΩ
A: IOUT, 200mA/div
B: VGATE, 20V/div
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
_______________________________________________________________________________________ 7
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA= +25°C, unless otherwise specified.)
SHORT-CIRCUIT RESPONSE
(VCC = +48V EXPANDED TIME SCALE)
MAX5913/4 toc22
0
A
B
0
40µs/div
ON = RLYON = VDD, RL = 1Ω, RRTIM = 2kΩ
A: IOUT, 200mA/div
B: VGATE, 20V/div
PEAK SHORT-CIRCUIT RESPONSE
(VCC = +48V EXPANDED TIME SCALE)
MAX5913/4 toc23
0
A
B
0
1µs/div
ON = RLYON = VDD, RL = 1Ω, RRTIM = 2kΩ
A: IOUT, 5A/div
B: VGATE, 20V/div
SHORT-CIRCUIT RESPONSE
(VCC = +57V)
MAX5913/4 toc24
0
A
B
0
1ms/div
ON = RLYON = VDD
A: IOUT, 200mA/div
B: VGATE, 20V/div
PEAK SHORT-CIRCUIT RESPONSE TIME
(VCC = +57V, EXPANDED TIME SCALE)
MAX5913/4 toc26
0
A
B
0
1µs/div
ON = RLYON = VDD, RL = 1Ω, RRTIM = 2kΩ
A: IOUT, 5A/div
B: VGATE, 20V/div
SHORT-CIRCUIT RESPONSE
(VCC = +72V)
MAX5913/4 toc27
A
B
0
0
1ms/div
ON = RLYON = VDD
A: IOUT, 200mA/div
B: VGATE, 50V/div
SHORT-CIRCUIT RESPONSE
(VCC = +57V, EXPANDED TIME SCALE)
MAX5913/4 toc25
0
A
B
0
40µs/div
ON = RLYON = VDD, RL = 1Ω, RRTIM = 2kΩ
A: IOUT, 200mA/div
B: VGATE, 20V/div
tO vs RRTIM
MAX5913/4 toc33
RRTIM (kΩ)
tO (ms)
3530252015105
20
40
60
80
100
120
0
040
TA = -40°C, +25°C, +85 °C
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
8 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA= +25°C, unless otherwise specified.)
SHORT-CIRCUIT RESPONSE
(VCC = +72V, EXPANDED TIME SCALE)
MAX5913/4 toc28
A
B
0
0
40µs/div
ON = RLYON = VDD, RL = 1Ω, RRTIM = 2kΩ
A: IOUT, 200mA/div
B: VGATE, 50V/div
PEAK SHORT-CIRCUIT RESPONSE TIME
(VCC = +72V, EXPANDED TIME SCALE)
MAX5913/4 toc29
A
B
0
0
1µs/div
ON = RLYON = VDD, RL = 1Ω, RRTIM = 2kΩ
A: IOUT, 5A/div
B: VGATE, 50V/div
OPEN-CIRCUIT THRESHOLD
vs. INPUT VOLTAGE
MAX5913/14 toc30
INPUT VOLTAGE (V)
THRESHOLD VOLTAGE (mV)
696660 6342 45 48 51 54 5736 39
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
2.0
33 72
TA = +25°C
TA = +85°C
TA = -40°C
4.0
3.5
3.0
2.5
2.0
-40 10-15 35 60 85
OPEN-CIRCUIT THRESHOLD
vs. TEMPERATURE
MAX5913/14 toc31
TEMPERATURE (°C)
THRESHOLD VOLTAGE (mV)
VCC = +36V, +48V,
+57V, AND +72V
OPEN-CIRCUIT GLITCH DELAY
MAX5913/4 toc32
A
B
0
0
40ms/div
ON = RLYON = VDD, STATOUT = LOW
A: IOUT, 20mA/div
B: VSTAT, 5V/div
C: VGATE, 20V/div
0
C
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
_______________________________________________________________________________________ 9
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA= +25°C, unless otherwise specified.)
to vs. INPUT VOLTAGE
MAX5913/4 toc34
VDD (V)
tO (ms)
3.63.33.02.72.42.1
0
25
50
75
100
125
1.8
RRTIM = 40kΩ
RRTIM = OPEN RRTIM = 2kΩ
RETRY DUTY CYCLE vs. DC
MAX5913/4 toc35
0
A
B
0
C
0
100ms/div
VGATE = 20V/div, RRTIM = 2kΩ
A: VGATE, 20V/div, DC = FLOATING (4%)
B: VGATE, 20V/div, DC = VDD (2%)
C: VGATE, 20V/div, DC = GND (1%)
CHANNEL-TO-CHANNEL CROSSTALK
MAX5913/4 toc36
20µs/div
VTEST
5V/div
VOUT
10mV/div
SEE FIGURE 4 FOR TEST CIRCUIT
Pin Description
PIN NAME FUNCTION
1FAULT
Fault Output. FAULT is an open-drain output that goes low when a fault is detected on any
of the four channels. FAULT is low when an OC (open circuit) is detected, or when the
MAX5913/MAX5914 is in auto-retry caused by an overcurrent condition. When RTRYEN is
low, and the channel switch is latched off due to overcurrent condition, FAULT remains
low until ON_ is driven low.
2, 3, 4, 5
STAT1,
STAT2,
STAT3,
STAT4
Status Outputs. STAT_ are push-pull outputs. Depending on the STATOUT pin status,
STAT_ flags either the Power-OK_ or Port-OC_ status.
Power-OK_ high indicates:
a) ON_ input is high
b) The switch port is fully on and startup is completed (VCSP_ - VOUT_) < VSWON
c) Input voltage is above VUVLO
d) Switch is not in current limit.
Power-OK_ low indicates a fault with any of the above conditions.
Port-OC_ output high indicates that the switch is latched off because the switch current is
less than the open current threshold Port-OC is low otherwise.
6, 10, 24, 28 CSP4, CSP3, CSP2,
CSP1
C ur r ent- S ense P osi ti ve Inp ut. C onnect to V
CC and p l ace a cur r ent- sense r esi stor fr om C S P _
to D RAIN _. U se Kel vi n sense tr ace fr om cur r ent- sense r esi stor to C S P _ ( see Fi g ur e 7) .
7, 11, 23, 27 DRAIN4, DRAIN3,
DRAIN2, DRAIN1
MOSFET Drain Current-Sense Negative Input. Connect to drain of power MOSFET and
connect a current-sense resistor from CSP_ to DRAIN_. Use Kelvin sense trace from
current-sense resistor to DRAIN_ (see Figure 7).
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
10 ______________________________________________________________________________________
Pin Description (continued)
PIN NAME FUNCTION
8, 12, 21, 25 OUT4, OUT3,
OUT2, OUT1
MOSFET Source Output Voltage Sense. Connect to power MOSFET source through a
100Ω series resistor.
9, 13, 22, 26 GATE4, GATE3,
GATE2, GATE1
MOSFET Gate Driver Output. The MAX5913/MAX5914 regulate the gate-drive voltage to
(VCC + 9V) to fully turn on the power N-channel MOSFET. GATE_ sources 10µA during
startup to slowly turn-on the MOSFET switch. GATE_ sinks 1mA to turn-off the MOSFET
switch.
14 VRLY Relay Supply Voltage Input. Referenced to DGND.
15, 16, 18,
19
RLYD3, RLYD4,
RLYD1, RLYD2
Relay-Drive Output. For the MAX5913, RLYD_ sinks 100mA when the relay driver is
enabled. For the MAX5914, RLYD_ sources 1mA when the relay driver is enabled.
17, 30 DGND Digital Ground. All logic voltages are referred to DGND. The voltage difference between
DGND and AGND can be up to ±4V.
20 AGND Analog Ground. All analog voltages are referred to AGND.
29 VCC
Analog Power Supply. Connect VCC to +35V to +72V power supply. UVLO circutry turns
off MOSFET switch and relay for VCC < VUVLO. Bypass VCC to AGND with a 1µF
capacitor.
31 OCEN
Open-Circuit Detector Enable Input. Drive OCEN high to enable open-circuit detector, or
drive low to disable. When enabled, the open-circuit detector waits for a 900ms delay
after Power-OK conditions are met before enabling the open-circuit detector function.
32 STATOUT
Status Output Multiplexer (MUX) Control Input. Controls the signal MUX into the STAT_
outputs. Drive STATOUT high to route Power-OK_ status to STAT_ outputs, or drive
STATOUT low to route Port-OC_ status to STAT_ outputs.
33 RTRYEN
Auto-Retry Enable Input. Drive RTRYEN high to enable auto-retry. Drive RTRYEN low to
enable switch latch-off mode. When switch is latched off, a high-to-low transition on the
ON_ control input clears the latch.
34 DC
Duty-Cycle Programming Input. DC sets the minimum off-time after an overcurrent
condition latches off the switch. When RTRYEN is high, DC sets the auto-retry duty cycle.
Drive DC low for 1% duty cycle, drive DC high for 2%, or leave DC floating for 4%
duty cycle.
35, 37, 39,
41
RLYON1, RLYON2,
RLYON3, RLYON4
Relay-Driver Control Input. Drive RLYON_ high to enable RLYD_, drive RLYON_ low to
turn off MOSFET switch for the channel and disable RLYD_.
36, 38, 40,
42
ON1, ON2, ON3,
ON4
MOSFET Switch Control Input. Drive ON_ high to enable GATE_ to turn on MOSFET
switch. RLYON_ must be high to enable the switch. Drive ON_ low to disable the switch.
Pulling ON_ low also resets the latch when RTRYEN is low or if the switch is latched off
due to open-circuit detection.
43 RTIM
Timing Oscillator Frequency Set Input. Connect a 2kΩ to 40kΩ resistor from RTIM to
DGND to set the maximum continuous overcurrent time, tO. Leave RTIM unconnected to
set default 6.4ms tO.
44 VDD Digital Power Supply. Bypass VDD to DGND with a 1µF capacitor.
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
______________________________________________________________________________________ 11
Detailed Description
The MAX5913/MAX5914 quadruple hot-swap controllers
provide Power-Over-MDI, also known as Power-Over-
LAN systems (Figure 5). The MAX5913/MAX5914 enable
control of four external N-channel MOSFET switches
from a single VCC ranging from +35V to +72V, with tim-
ing control and current-limiting functions built in.
Features include undervoltage lockout (UVLO), 100mA
relay drivers, dual-level current sense, foldback current
limit, programmable overcurrent time and auto-retry
periods, internal charge pumps to drive external MOS-
FET and soft-start, port status output indicating Power-
OK or open-circuit conditions (Figure 6).
Switch and Relay Control Inputs
The MAX5913/MAX5914 ON_ inputs turn on the corre-
sponding MOSFET switch. Driving ON_ high turns on
the switch if the corresponding RLYON is driven high,
and VCC > VUVLO for more than 25.6ms. Driving
RLYON_ high immediately turns on the corresponding
relay, and activates the 25.6ms delay after which the
corresponding ON_ input is active. Driving RLYON_ low
immediately turns off the switch and activates a 3.2ms
delay after which the relay is turned off. These internal
delays safely allow driving ON_ and RLYON_ simulta-
neously. The relay is turned on while the switch is off so
that there is no voltage across the relay contacts. The
relay is turned off while the switch is off so that there is
no current flowing when the relay contacts are opened
(see Figure 3).
Input Voltage and UVLO
The MAX5913/MAX5914 operate from +35V to +72V
supply voltage. VCC powers the MAX5913/MAX5914
analog circuitry and is monitored continuously during
startup and normal operation. The MAX5913/MAX5914
keep all MOSFET switches and relay drivers securely
off before VCC rises above VUVLO. The MAX5913/
MAX5914 turn off all MOSFET switches and relay dri-
vers after VCC falls below VUVLO - VUVLO,H.
Startup
When the turn-on condition is met (see Input Voltage
and UVLO and Switch and Relay Control Inputs sec-
tions), the MAX5913/MAX5914 slowly turn on the exter-
nal MOSFET switch by charging its gate using a
constant current source, IGATE (10µA typ). The gate
voltage slope is determined by the total gate capaci-
tance CGATE connected to this node. Since the output
voltage follows the gate voltage, thus the output rises
with a slope determined by:
If a capacitor load is connected to the output the total
current through the FET is:
where CLis the load capacitance and ILis the current
required by any load connected to the output during
the startup phase.
If the current through the FET reaches the programmed
current-limit value:
the internal current-limit circuitry activates and regu-
lates this FET current to be a value, ILIM, that depends
on VOUT (IFLBK) (Figure 8). See the Current Sensing
and Regulation section for more information. In this
case the maximum rate of change of the output is
determined by:
The formula shows the necessity for ILIM to be larger
than ILin order to allow the output voltage to rise. The
foldback function is active as long as the circuit is in
overcurrent condition. Should the overcurrent condition
persist for a period longer than the maximum time tO,
the switch is latched off and GATE_ is discharged to
ground with a 1mA pulldown current.
If auto-retry is enabled, the switch turns on again after a
waiting period, tOFF, which is determined by the pro-
grammed duty cycle.
After the startup, the internal charge pumps provide
(VCC + 9V) typical gate overdrive to fully turn on the
switch. When the switch is fully on (voltage drop across
the switch is ≤1.5V), and the switch is not in current
limit, the Power-OK signal is asserted.
Current Sensing and Regulation
The MAX5913/MAX5914 control port current with using
two voltage comparators (dual-level detection) that
sense the voltage drop across an external current-
sense resistor. Connect CSP_ to VCC and connect a
current-sense resistor between CSP_ and DRAIN_.
Kelvin sensing should be used as shown in Figure 7.
∆
∆
V
t
II
C
OUT LIM L
L
=−
IV
R
MAX SC
SENSE
=
II C
CI
GATE L
GATE
L
=+
∆
∆
V
t
I
C
OUT GATE
GATE
=
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
12 ______________________________________________________________________________________
The first comparator compares the sensed voltage
against VSC threshold (typically 142.5mV). Choose a
sense resistor as follows:
RSENSE = VSC / IMAX
where IMAX is the maximum current allowed through
the switch.
When IMAX is reached, foldback current-limit circuitry
regulates the current limit as a function of VOUT (Figure
8). As VOUT approaches zero the maximum voltage
drop across the sense resistor is lowered to a minimum
value of 48mV (typ). This foldback feature helps reduce
the power dissipation in the external power FET during
output overload and output short-circuit conditions. If a
load with very low activation voltage is permanently
connected to the output, make the minimum limit cur-
rent sufficiently larger than the load current. If the load
current indeed exceeds the foldback-limit value the
MAX5913/MAX5914 are not able to power-up the
switch.
Test Circuits and Timing Diagrams
VUVLO
VCC
VGATE
tD, UVLO
+1V
VIH
VIL
+1V
RLYON
RLYD
(MAX5913)
tON_DEL
tOFF_DEL
VRLY
VGATE
+42V
3.3V
DGND
RLYON1
ON1
ON2
RLYON2
CSP2
CSP1
DRAIN2 OUT2
270µF
270µF
270µF
470µF
270µF
0.33Ω
200Ω
100Ω
100Ω
0.33Ω
GATE2
DRAIN1 OUT1GATE1
VOUT
VCC
VTEST
MAX5913/MAX5914
(VCC - VOUT) ≤ 1.5V
(POWER-OK IS GOOD)
VCC
tOC
VGATE
tLPFD
+1V
OC DETECTOR ENABLED
(INTERNAL SIGNAL)
Figure 1. UVLO Deglitch Delay
Figure 3. Port Turn-On Delay, Relay Turn-Off Delay Figure 4. Channel-to-Channel Crosstalk Test Circuit
Figure 2. Open-Circuit Detector Deglitch Delay
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
______________________________________________________________________________________ 13
A second comparator with a detection threshold of
3VSC activates a fast 15mA pulldown of the gate. The
purpose of this comparator is to rapidly discharge the
gate when a momentary current peak overstresses the
external FET helping the regulation to act more rapidly.
The sense resistor is also used to detect an open-circuit
or low-current condition with a typical threshold of 3mV.
Open-Circuit Detection
The MAX5913/MAX5914 detect when a port has low
current or is open circuit, and turn off the switch to that
port. After the switch is turned on and the Power-OK
conditions are met, the open-circuit detector is enabled
after a 900ms delay. The open-circuit voltage threshold
is set at 3mV across the current-sense resistor. Drive
OCEN high to enable open-circuit detectors for all four
ports. Drive OCEN low to disable the detectors. Each
port has an open-circuit flag that can be read from
STAT_ outputs when the STATOUT is low. STAT_ output
high indicates that the switch is latched off due to an
open-circuit condition on that port. To reset the latch
pull ON_ low and then high to restart (Table 1).
Output Voltage Sense and Power-OK
The MAX5913/MAX5914 sense the output voltage of
the port at the source of the external MOSFET switch.
FDT3612
N
VRLY
VCC
VRLY
VDD
RTIM
+12V
+3.3V
DIGITAL
INTERFACE
OUTPUTS
DIGITAL
INTERFACE
INPUTS
DGND AGND RLYD1 RLYD4
CSP1
DRAIN1
OUT1
1.0µF
CSP4
DRAIN4
GATE4
OUT4
2kΩ
0.33Ω
100Ω
100Ω
0.33Ω
1kΩ
GATE1
FAULT
STAT1
STAT2
STAT3
STAT4
VCC
PORT 1
ON1
ON2
ON3
ON4
RLYON1
RLYON2
RLYON3
RLYON4
OCEN
RTRYEN
STATOUT
DC
VCC = +35V TO +72V
MAX5913
FDT3612
N
K4
NO
K1
NO
VRLY
PORT 4
1µF
Figure 5. Typical Application Circuit
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
14 ______________________________________________________________________________________
Internally the circuit compares the output voltage with
VCC to determine when the FET is completely on. A
“Power-OK” condition is met when:
(VCC - VOUT) ≤1.5V
The internal circuit monitors VOUT to determine the
value of the foldback current when the circuit goes into
current-limit conditions. The value of the current limit
decreases as the output voltage decreases in order to
limit the power dissipation of the FET. The nonlinear
relationship between VOUT and ILIM is depicted in
Figure 8.
The foldback circuit is active whenever the MAX5913/
MAX5914 is in current-limit mode after an overcurrent
condition has been detected.
Connect a catch diode to analog ground and a 100Ω
resistor in series with OUT_ to limit the current during
negative inductive kicks that can bring OUT_ below the
ground potential (Figure 5).
Relay Drivers
The MAX5913/MAX5914 include on-chip relay drivers,
RYLD_, capable of sinking 100mA. When RLYON_
goes high the MAX5913/MAX5914 immediately enable
the relay driver, and the corresponding ON_ switch
control input is delayed 25.6ms to allow the relay to
close under a zero-voltage condition. When RLYON_
goes low, the MAX5913/MAX5914 immediately turn off
the corresponding switch, and then turn off the relay
driver after a 3.2ms delay, ensuring the relay contacts
open under a zero-current condition. The polarity of the
FOLDBACK
NL CONTROL
FROM LOGIC
CONTROLLER
DRAIN
RSENSE
GATE
TO LOGIC
CONTROLLER
CSP
10µA
8µA
1mA
OUT
OCEN ON
AGND DGND
RLYON RLYD
VRLY
VCC
CHARGE PUMP
POK COMPARATOR
DELAY
DUAL LEVEL
DETECTION
1mA
VDD
1.236V
UVLO
RTIMDCRTRYEN
OPEN-CIRCUIT
DETECTOR
DC COUNTER
RESET LOGIC
RELAY
CONTROL
TIMING
OSCILLATOR
LOGIC
CONTROLLER
CSP -1.5V
3mV
142.5mV
420mV
VDD
DGND
Figure 6. Functional Diagram
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
______________________________________________________________________________________ 15
MAX5913 RLYD_ is opposite to that of the MAX5914.
For the MAX5913, upon the assertion of the RLYON_
input RLYD_ sinks 100mA to DGND. For the MAX5914
when RLYON_ is high, an internal 1mA current source
pulls up RLYD_ to VDD. A 100mA catch diode is inter-
nally connected between RYLD_ and VRLY to protect
the MAX5913/MAX5914 from inductive kicks from the
relay coil. VRLY must be connected to the high-side
relay supply voltage.
Programmable Timing, RTIM
An external resistor from RTIM to DGND sets the fre-
quency of the internal oscillator upon which tOand the
auto-retry times are based.
Use 2kΩto 40kΩresistors for RRTIM.
tO= (RRTIM / 2kΩ) (6.4ms)
If RTIM is unconnected (floating), an internal resistor
sets tOto a nominal 6.4ms.
Auto-Retry and Programmable Duty Cycle
The MAX5913/MAX5914 feature auto-retry with
adjustable duty cycle. Driving RTRYEN high enables
the auto-retry function. When the switch encounters an
overcurrent for a period greater than tOthe switch is
turned off, and remains off for a tOFF programmed by
DC, a three-level input. After the tOFF period, the switch
is automatically turned on again. When the port
encounters a continuous overload or short-circuit con-
dition, the switch turns on and off repeatedly with the
on duty cycle of 1%, 2%, or 4% depending on the DC
input state (Table 2). When RTRYEN is low, the auto-
retry is disabled, and a fault condition at the switch
turns the switch off and the switch remains latched off.
Driving the corresponding ON control input low resets
the latch. Pulling ON high to turn on the switch.
However, the MAX5913/MAX5914 always waits a mini-
mum time tOFF,before restarting the switch.
Logic Interface and Status Outputs
The MAX5913/MAX5914 logic interface controls the
device functionality. All the basic control functions for
the four switches are separated. ON_ enables individual
on/off control of each MOSFET (the corresponding relay
must be on to turn on the switch). RLYON_ enables indi-
vidual on/off control of each relay. STAT_ indicates
Power-OK or Port-OC (open circuit) status of each
switch. The other logic pins are common to all four
switches. A single FAULT output goes low when any of
the four channels is latched off. Driving OCEN high
enables the open-circuit detectors. Driving RTRYEN
high enables the auto-retry function, RTRYEN low
enables the switch latch-off function. DC, a three-level
logic input, programs the duty cycle. The STATOUT
input selects the signal multiplexed at STAT_ outputs
(Table 1.). Driving STATOUT high routes Power-OK sta-
tus to the STAT_ outputs. Driving STATOUT low routes
Port-OC status to the STAT_ outputs.
Fault Management
UVLO and Power-OK
The MAX5913/MAX5914 monitor the VCC input voltage
and each switch’s current and voltage to determine
Power-OK, overcurrent, or Port-OC status. When VCC
falls below the UVLO threshold, FAULT goes low and
all four switches and relays are turned off. When the
volage across the switch is less than 1.5V, the switch is
fully on, and if the switch is not in current limit or open
circuit, Power-OK status is good (high).
Open-Circuit Faults
With the open circuit detector enabled, when any
switch current falls below the open-circuit detector
PORT_ CONDITION OCEN STATOUT STAT_
Enabled. Switch fully on and not in current limit x H H
(Power-OK_ is good)
Enabled. Switch in current limit, or VDS > 1.5V x H L
(Power-OK_ is not good)
Enabled. Switch current is less than OC threshold,
port is latched off HL H
(Port-OC_ , Port current is low or zero)
Enabled. Switch fully on and output current is greater
than OC threshold HL L
(Port-OC_ , Port current is good)
Disabled L L L
Table 1. Status Output
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
16 ______________________________________________________________________________________
threshold current, the open-circuit detector turns off the
switch after a 25.6ms delay, FAULT goes low and the
Port-OC flag is set for that switch. To clear the switch
latched-off condition, FAULT and Port-OC flags drive
the corresponding ON input low.
Overcurrent Faults
When an on switch current exceeds the current-limit
threshold, foldback circuitry activates and regulates the
switch current. When current limit lasts for longer than
tO, the switch latches off. The Power-OK status flag is
set low, and the FAULT flag is set. If auto-retry is
enabled, the switch remains off for a period tOFF. If
auto-retry is disabled, the switch remains latched off,
and FAULT is low. Reset the latch and FAULT by dri-
ving corresponding ON_ low.
Applications Information
Considerations for circuit design include output capaci-
tor requirements, current-limit requirements, setting the
maximum on-time in current limit, and choosing a suit-
able MOSFET and on-time duty cycle in auto-retry.
Output Capacitor Requirements
The load capacitor requirements should be determined
first, as this affects the required startup.
Current-Limit Requirements
(Choosing RSENSE)
The current limit should be set to at least 20% higher
than the expected full load current. If current limit is
also used to control startup current, then set this limit
high enough so that the output voltage can rise and
settle before tOelapses (see Setting tOsection below).
Setting tO(Choosing RRTIM)
Choose the tOtime by connecting a 2kΩto 40kΩresistor
from RTIM to DGND. The minimum 6.4ms tOis set with
RRTIM = 2kΩ. The maximum 128ms tOis set with RRTIM
= 40kΩset according to the following equation:
tO= (RRTIM / 2kΩ) (6.4ms).
tOshould be chosen appropriately, depending on the
startup condition. There are two cases:
1) For startup without current limit, when
the startup current does not reach the maximum cur-
rent-limit threshold and tOwill not activate during
startup condition. In this case, set tOto a small
value, but large enough to allow the switch to remain
on during large output load-current transients. The
smaller the tO, the faster the MAX5913/MAX5914
turn off the external FET in case of output overload
or short-circuit condition.
2) For startup with current limit, when
which is expected when
is large, tOmust be set to be long enough to allow the
output voltage to rise and settle before tOelapses. In
this case, tOmust satisfy the following equation:
where VCC is the input voltage and given that IL< ILIM.
Choosing Power MOSFET
The FET must withstand a short-circuit condition where
its power dissipation is PDISS = VCC ✕ILIM. The FET
must have sufficient thermal capacitance to prevent
thermal heating damage during the tOtime.
Choose Duty Cycle (setting DC)
The duty cycle can be adjusted to allow time for heat to
dissipate between tOcycles, allowing use of smaller
MOSFETs with lower thermal capacitance. For smaller
duty cycle, a smaller FET is sufficient. See Table 2 for
setting the duty cycle.
The auto-retry off-time should not be too long to keep
system wait time during retry period to a reasonable
value. For example, when tOis set to 128ms and duty
cycle is set to 1%, the retry time is 99 ✕128ms = 12.7s.
Application Circuits
In a typical LAN system there are two ways to deliver
power over the LAN cable. Power can be supplied to
the unused cable pairs, or power can be supplied over
the signal pairs (Figures 9 and 10).
tC
II
CVV
II
OL
MAX L
LCC
MAX L
=−+−
−
18
2
3
18
C
C
L
GATE
II C
CIV
R
GATE L
GATE LSC
SENSE
=+
≥
II C
CIV
R
GATE L
GATE LSC
SENSE
=+<
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
______________________________________________________________________________________ 17
SENSE
RESISTOR
CSP_
DRAIN_
HIGH-CURRENT PATH
MAX5913
MAX5914
Figure 7. Recommended Layout for Kelvin-Sensing Current
Through Sense Resistor
ILIM
IMAX/3
0 18V VOUT
IMAX = VSC
RSENSE
∆
Figure 8. Foldback Current-Limit Response
DC tOFF DUTY CYCLE
0 99 ✕ tO1%
1 49 ✕ tO2%
Open 24 ✕ tO4%
Table 2. Duty Programming Cycle
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
18 ______________________________________________________________________________________
N
PD
CAT 5
RJ45
POWERED
DEVICE
(IP PHONE, ETC.)
DATA
RJ45
+48V POWER OVER
SIGNAL PAIRS
LAN SWITCH
+48V
+48V
OUT
MAX5913
MAX5914
Figure 9. Power Sent Over Signal Pairs
NPD
CAT 5
CAT 5
RJ45
POWERED
DEVICE
(IP PHONE, ETC.)
RJ45
RJ45RJ45
+48V POWER OVER
SPARE PAIRS
MIDSPAN HUB
+48V
+48V
OUT
MAX5913
MAX5914
Figure 10. Power Sent Over Spare Pairs
Chip Information
TRANSISTOR COUNT: 14,622
PROCESS: BiCMOS
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
______________________________________________________________________________________ 19
N
VRLY
VCC
VRLY
VDD
RTIM
+12V
+3.3V
DIGITAL
INTERFACE
OUTPUTS
DIGITAL
INTERFACE
INPUTS
DGND AGND RLYD1 RLYD4
CSP1
DRAIN1
OUT1
CSP4
DRAIN4
GATE4
OUT4
GATE1
FAULT
STAT1
STAT2
STAT3
STAT4
VCC
PORT 1
ON1
ON2
ON3
ON4
RLYON1
RLYON2
RLYON3
RLYON4
OCEN
RTRYEN
STATOUT
DC
VCC = +35V TO +72V
MAX5913
N
VRLY
PORT 4
Typical Operating Circuit
MAX5913/MAX5914
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
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.
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
MQFP44.EPS
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)