MAX5921BESA+ ,-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Currentfeatures over these devices.and Current SpikesThe MAX5921/MAX5939 provide a controlled turn-on to♦ ..
MAX5921BESA+ ,-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown CurrentFeaturesThe MAX5921/MAX5939 hot-swap controllers allow a cir-♦ Allows Safe Board Insertion and Remo ..
MAX5921EESA+ ,-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown CurrentApplicationsMAX5921AESA -40°C to +85°C 8 SOTelecom Line CardsMAX5921BESA -40°C to +85°C 8 SONetwork ..
MAX5922AEUI ,+48V, Single-Port Network Power Switch For Power-Over-LANfeatures a programmable undervoltagelockout (UVLO) that keeps the device in shutdown until Current ..
MAX5922AEUI+ ,+48V, Single-Port Network Power Switch For Power-Over-LANApplicationspare pairs. In midspan mode, a detection collision♦ Input Logic Signals Compatible with ..
MAX5922AEUI+ ,+48V, Single-Port Network Power Switch For Power-Over-LANfeatures a programmable undervoltagelockout (UVLO) that keeps the device in shutdown until♦ Current ..
MAZ8091-H ,Silicon planar typeElectrical Characteristics T = 25°CaParameter Symbol Conditions Min Typ Max UnitForward voltage V ..
MAZ8091-L ,Silicon planar typeelectrical characteristicsZ Zwithin part numbersReverse current I V ··············· Specified value ..
MAZ8091M ,Silicon planar typeFeatures•Extremely low noise voltage caused from the diode (2.4V to 39V,1/3 to 1/10 of our conventi ..
MAZ8091-M ,Silicon planar typeelectrical characteristicsZ Zwithin part numbersReverse current I V ··············· Specified value ..
MAZ8100-H ,Silicon planar typeZener DiodesMAZ8000 SeriesSilicon planar typeUnit : mmFor stabilization of power supplyKA
MAZ8100-L ,Silicon planar typeElectrical characteristics within part numbers T = 25°CaTemperaturecoefficient ofZener voltage Rev ..
MAX5921AESA+T-MAX5921BESA+-MAX5921EESA+
-48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current
General DescriptionThe MAX5921/MAX5939 hot-swap controllers allow a cir-
cuit card to be safely hot plugged into a live backplane.
The MAX5921/MAX5939 operate from -20V to -80V and
are well suited for -48V power systems. These devices
are pin compatible with both the LT1640 and LT4250 and
provide improved features over these devices.
The MAX5921/MAX5939 provide a controlled turn-on to
circuit cards preventing damage to board connectors,
board components, and preventing glitches on the
power-supply rail. The MAX5921/MAX5939 provide
undervoltage, overvoltage, and overcurrent protection.
These devices ensure that the input voltage is stable
and within tolerance before applying power to the load.
Both the MAX5921 and MAX5939 protect a system
against overcurrent and short-circuit conditions by turn-
ing off the external MOSFET in the event of a fault con-
dition. The MAX5921/MAX5939 protect against input
voltage steps by limiting the load current to a safe level
without turning off power to the load.
The device features an open-drain power-good status
output, PWRGDor PWRGD for enabling downstream
converters (see Selector Guide). A built-in thermal shut-
down feature is also included to protect the external
MOSFET in case of overheating. The MAX5939 features
a latched fault output. The MAX5921 contains built-in
autoretry circuitry after a fault condition.
The MAX5921/MAX5939 are available in an 8-pin SO
package and operate in the extended -40°C to +85°C
temperature range.
ApplicationsTelecom Line Cards
Network Switches/Routers
Central-Office Line Cards
Server Line Cards
Base-Station Line Cards
FeaturesAllows Safe Board Insertion and Removal
from a Live -48V BackplanePin-Compatible with LT1640 and LT4250Circuit Breaker Immunity to Input Voltage Steps
and Current Spikes450mA GATE Pulldown Current During Short-
Circuit ConditionExponential GATE Pulldown CurrentWithstands -100V Input Transients with No
External ComponentsProgrammable Inrush and Short-Circuit Current
LimitsOperates from -20V to -80VProgrammable Overvoltage ProtectionProgrammable Undervoltage Lockout
with Built-In Glitch FilterOvercurrent Fault IntegratorPowers Up into a Shorted LoadPower-Good Control OutputThermal Shutdown Protects External MOSFET
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown CurrentGATE
SENSEVEE
VDD
DRAINOV
PWRGD
(PWRGD)
TOP VIEW
MAX5921
MAX5939
() FOR MAX5921B/F AND MAX5939B/F.
Pin Configuration
Ordering Information19-2946; Rev 1; 2/06
PARTTEMP RANGEPIN-PACKAGE
MAX5921AESA-40°C to +85°C8 SO
MAX5921BESA-40°C to +85°C8 SO
Typical Operating Circuit and Selector Guide appear at end
of data sheet.
Ordering Information continued at end of data sheet.
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown Current
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VEE= 0V, VDD= 48V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C, unless otherwise noted.) (Notes 1, 4)
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.
All Voltages Are Referenced to VEE, Unless Otherwise Noted
Supply Voltage (VDD- VEE )................................-0.3V to +100V
DRAIN, PWRGD, PWRGD....................................-0.3V to +100V
PWRGD to DRAIN .............................................… -0.3V to +95V
PWRGD to VDD.......................................................-95V to +85V
SENSE (Internally Clamped).................................-0.3V to +1.0V
GATE (Internally Clamped)....................................-0.3V to +18V
UV and OV..............................................................-0.3V to +60V
Current into SENSE...........................................................+40mA
Current into GATE...........................................................+300mA
Current into Any Other Pin................................................+20mA
Continuous Power Dissipation (TA= +70°C)
8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
POWER SUPPLIESOperating Input Voltage RangeVDD2080V
Supply CurrentIDDCurrent into VDD with UV = 3V, OV, DRAIN,
SENSE = VEE, GATE = floating0.72mA
GATE DRIVER AND CLAMPING CIRCUITSGate Pullup CurrentIPUGATE drive on, VGATE = VEE-30-45-60µA
Gate Pulldown CurrentIPDVSENSE - VEE = 100mV, VGATE = 2V (Note 2)245070mA
External Gate DriveΔVGATEVGATE - VEE, steady state, 20V ≤ VDD ≤ 80V1013.518V
GATE to VEE Clamp VoltageVGSCLMPVGATE - VEE, IGS = 30mA1516.418V
CIRCUIT BREAKERCurrent-Limit Trip VoltageVCLVCL = VSENSE - VEE405060mV
SENSE Input CurrentISENSEVSENSE = 50mV-1-0.20µA
UNDERVOLTAGE LOCKOUTSupply Internal Undervoltage
Lockout Voltage HighVUVLOHVDD increasing13.815.417.0V
Supply Internal Undervoltage
Lockout Voltage LowVUVLOLVDD decreasing11.813.415.0V
UV INPUTUV High ThresholdVUVHUV voltage increasing1.2401.2551.270V
UV Low ThresholdVUVLUV voltage decreasing1.1051.1251.145V
UV HysteresisVUVHY130mV
UV Input CurrentIINUVUV = VEE-0.50µA
OV INPUTOV High ThresholdVOVHOV voltage rising1.2351.2551.275V
OV Low ThresholdVOVLOV voltage decreasing1.1891.2051.221V
OV Voltage Reference HysteresisVOVHY50mV
OV Input CurrentIINOVOV = VEE-0.50µA
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown Current
ELECTRICAL CHARACTERISTICS (continued)(VEE= 0V, VDD= 48V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C, unless otherwise noted.) (Notes 1, 4)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
PWRGD OUTPUT SIGNAL (REFERENCED TO DRAIN)DRAIN Input CurrentIDRAINVDRAIN = 48V1080250µA
DRAIN Threshold for PWRGDVDLVDRAIN - VEE threshold for power-good
condition, DRAIN decreasing1.11.72.0V
GATE High ThresholdVGHΔVGATE - VGATE, decreasing1.01.62.0V
V PWRGD = 80V, VDRAIN = 48V10PWRGD, PWRGD Output
LeakageIOHVPWRGD = 80V, VDRAIN = 0V10µA
PWRGD Low Voltage
(V PWRGD - VEE)VOLVDRAIN - VEE < VDL, ISINK = 5mA
(A, E versions)0.110.4V
PWRGD Low Voltage
(VPWRGD - VDRAIN)VOLVDRAIN = 5V, ISINK = 5mA (B, F versions)0.110.4V
OVERTEMPERATURE PROTECTIONOvertemperature ThresholdTOT(TH)Junction temperature, temperature rising135°C
Overtemperature HysteresisTHYSSee Thermal Shutdown section20°C
AC PARAMETERSOV High to GATE LowtPHLOVFigures 1a, 20.5µs
UV Low to GATE LowtPHLUVFigures 1a, 30.4µs
OV Low to GATE HightPLHOVFigures 1a, 23.3µs
UV High to GATE HightPLHUVFigures 1a, 38.4ms
SENSE High to GATE LowtPHLSENSEFigures 1a, 4a1µs
A, B versions0.350.50.65
Current Limit to GATE LowtPHLCL
Time from continuous
current limit to GATE
shutdown (see Overcurrent
Fault Integrator section),
Figures 1b, 4bE, F versions1.42.02.6
Figures 1a, 5a; A and E versions8.2DRAIN Low to PWRGD Low
DRAIN Low to (PWRGD - DRAIN)
High
tPHLDL
Figures 1a, 5a; B and F versions8.2
Figures 1a, 5b; A and E versions8.2GATE High to PWRGD Low
GATE High to (PWRGD - DRAIN)
High
tPHLGH
Figures 1a, 5b; B and F versions8.2
TURN-OFFLatch-Off PeriodtOFF(Note 3)A, B, E, F versions128 x
tPHLCLms
Note 1:All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to VEE,
unless otherwise specified.
Note 2:Gate pulldown current after the current limit to GATE low (tPHLCL) time has elapsed.
Note 3:Minimum duration of GATE pulldown following a circuit breaker fault. The MAX5921_ automatically restarts after a circuit
breaker fault. The MAX5939_ is latched off and can be reset by toggling UV low. The GATE pulldown does not release until
tOFFhas elapsed.
Note 4:The min/max limits are 100% production tested at +25°C and +85°C and guaranteed by design at -40°C.
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown Current
Typical Operating Characteristics(VDD= +48V, VEE= 0V, TA = +25°C, unless otherwise noted.)
GATE PULLUP CURRENT
vs. TEMPERATURE
MAX5921TOC04
TEMPERATURE (°C)
GATE PULLUP CURRENT (
VGATE = 0V
GATE PULLDOWN CURRENT
vs. TEMPERATURE AFTER A FAULT
MAX5921TOC05
TEMPERATURE (°C)
GATE PULLDOWN CURRENT (mA)
VGATE = 2V
GATE PULLDOWN CURRENT
vs. OVERDRIVE DURING A CURRENT FAULT
MAX5921TOC06
OVERDRIVE (mV)
GATE PULLDOWN CURRENT (mA)
VGATE = 2V
GATE PULLDOWN CURRENT
vs. OVERDRIVE DURING A SHORT CIRCUIT
MAX5921TOC07
OVERDRIVE (mV)
GATE PULLDOWN CURRENT (mV)
VGATE = 2V
PWRGD OUTPUT LOW VOLTAGE
vs. TEMPERATURE (MAX5921A)
MAX5921TOC08
TEMPERATURE (°C)
PWRGD OUTPUT LOW VOLTAGE (mV)
IOUT = 5mA
PWRGD OUTPUT LEAKAGE CURRENT
vs. TEMPERATURE (MAX5921B)
MAX5921TOC09
TEMPERATURE (°C)
PWRGD OUTPUT LEAKAGE CURRENT (nA)
VDRAIN - VEE > 2.4V
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX5921TOC01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
TA = +85°C
TA = +25°C
TA = -40°C
GATE VOLTAGE
vs. SUPPLY VOLTAGE
MAX5921TOC02
SUPPLY VOLTAGE (V)
GATE VOLTAGE (V)
TA = +25°C
CURRENT-LIMIT TRIP VOLTAGE
vs. TEMPERATURE
MAX5921TOC03
TEMPERATURE (°C)
TRIP VOLTAGE (mV)
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown CurrentMAX5921
MAX5939
PWRGD/PWRGD
VEE
VDD
DRAIN
GATE
SENSE
5kΩV+
VOV
VUV
VSENSE
VDRAIN
+48V
Figure 1a. Test Circuit 1
MAX5921
MAX5939
VEE
VDD
DRAIN
GATE
SENSEVUV
+48V
+20V
10kΩ
10Ω
IRF530
0.1μF
PWRGD/PWRGD
Figure 1b. Test Circuit 2
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown Current
Timing Diagrams1.255V
tPHLOV
1.205V
tPLHOV
GATE
Figure 2. OV to GATE Timing
tPHLUV
1.125V1V
1.255V
tPLHUV
GATE
Figure 3. UV to GATE Timing
60mV
100mV
GATE
SENSE
VEE
tPHLSENSE
Figure 4a. SENSE to GATE Timing
tPHLCL1V
GATE
Figure 4b. Active Current-Limit Threshold
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown Current
Timing Diagrams (continued)DRAIN
PWRGD
PWRGD
DRAIN
1.4V
1.4V
VEE
VEE
VEE
tPHLDL
tPHLDL
VDCEN - VDRAIN = 0V
Figure 5a. DRAIN to PWRGD/PWRGD Timing
∆VGATE - VGATE = 0V
1.4V
GATE
PWRGD1VVEE
VEE
∆VGATE - VGATE = 0V
GATE
PWRGD
1.4V
VDCEN - VDRAIN = 0V
tPHLGH
tPHLGH
Figure 5b. GATE to PWRGD/PWRGD Timing
UVLOVDD AND
REFERENCE
GENERATOR
LOGIC
OUTPUT
DRIVER
GATE
DRIVER
MAX5921/MAX5939
REF
50mV
VDD
VDD
REF
VEESENSEGATEDRAIN
VDLVGH
∆VGATE
PWRGD
PWRGD
VEE
Block Diagram
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown Current
Detailed DescriptionThe MAX5921/MAX5939 integrated hot-swap controllers
for -48V power systems allow circuit boards to be safely
hot plugged into a live backplane without causing a
glitch on the power-supply rail. When circuit boards are
inserted into a live backplane, the bypass capacitors at
the input of the board’s power module or switching
power supply can draw large inrush currents as they
charge. Uncontrolled inrush currents can cause glitches
on the system power supply and damage components
on the board.
The MAX5921/MAX5939 provide a controlled turn-on to
circuit cards preventing damage to connectors, board
components, and prevent glitches on the power-supply
rail. Both the MAX5921/MAX5939 provide undervolt-
age, overvoltage, and overcurrent protection. The
MAX5921/MAX5939 ensure that the input voltage is sta-
ble and within tolerance before applying power to the
load. The device also provides protection against input
voltage steps by limiting the load current to a safe level
without turning off power to the load.
Pin Description
PIN
MAX5921A/
MAX5921E
MAX5939A/
MAX5939E
MAX5921B/
MAX5921F
MAX5939B/
MAX5939F
NAMEFUNCTIONPWRGD
Power-Good Signal Output. PWRGD is an active-low open-drain status output referenced
to VEE. PWRGD latches low when VDRAIN - VEE ≤ VDL and VGATE > ΔVGATE indicating a
power-good condition. PWRGD is open drain otherwise.PWRGD
Power-Good Signal Output. PWRGD is an active-high open-drain status output refer-
enced to DRAIN. PWRGD latches in a high-impedance state when VDRAIN - VEE ≤ VDL
and VGATE > ΔVGATE - VGH indicating a power-good condition. PWRGD is pulled low to
DRAIN otherwise.OV
Overvoltage Detection Input. OV is referenced to VEE. When OV is pulled above VOVH
voltage, GATE pulls low. GATE remains low until the OV voltage reduces to VOVH -
VOVHY.UV
Undervoltage Detection Input. UV is referenced to VEE. When UV is pulled above VUVH
voltage, the GATE is enabled. When UV is pulled below VUVL, GATE pulls low.
UV is also used to reset the circuit breaker after a fault condition. To reset the circuit
breaker, pull UV below VUVL. The reset command can be issued immediately after a fault
condition; however, the device will not restart until a tOFF delay time has elapsed after the
fault condition is removed.VEENegative Power-Supply Input. Connect to the negative power-supply rail.SENSE
Current-Sense Input. Connect to the external sense resistor and the source of the external
MOSFET. The voltage drop across the external sense resistor is monitored to detect
overcurrent or short-circuit fault conditions. Connect SENSE to VEE to disable the current-
limiting feature.GATEGate Drive Output. Connect to the gate of the external N-channel MOSFET.DRAIN
Output Voltage Sense Input. Connect to the output voltage node (drain of external N-
channel MOSFET). Place the MAX5921/MAX5939 such that DRAIN is close to the drain of
the external MOSFET for the best thermal protection.VDDPositive Power-Supply Input. This is the power ground in the negative supply voltage
system. Connect to the higher potential of the power-supply inputs.
MAX5921/MAX5939
-48V Hot-Swap Controllers with External
RSENSEand High Gate Pulldown Current
Board InsertionFigure 6a shows a typical hot-swap circuit for -48V sys-
tems. When the circuit board first makes contact with
the backplane, the DRAIN to GATE capacitance (Cgd)
of Q1 pulls up the GATE voltage to roughly IVEExgd/Cgd+ Cgs)I. The MAX5921/MAX5939 feature an
internal dynamic clamp between GATE and VEEto
keep the gate-to-source voltage of Q1 low during hot
insertion preventing Q1 from passing an uncontrolled
current to the load. For most applications, the internal
clamp between GATE and VEEof the MAX5921/
MAX5939 eliminates the need for an external gate-to-
source capacitor. The resistor R3 limits the current into
the clamp circuitry during card insertion.
Power-Supply RampingThe MAX5921/MAX5939 can reside either on the back-
plane or the removable circuit board (Figure 6a). Power
is delivered to the load by placing an external N-chan-
nel MOSFET pass transistor in the power-supply path.
After the circuit board is inserted into the backplane,
and the supply voltage at VEEis stable and within the
undervoltage and overvoltage tolerance, the
MAX5921/MAX5939 gradually turn on the external
MOSFET by charging the gate of Q1 with a 45µA cur-
rent source. Capacitor C2 provides a feedback signal
to accurately limit the inrush current.
The inrush current can be calculated:
IINRUSH= IPU x CL / C2
where CLis the total load capacitance, C3 + C4, and
IPUis the gate pullup current.
Figure 6b shows the inrush current waveform. The cur-
rent through C2 controls the GATE voltage. At the end
of the DRAIN ramp, the GATE voltage is charged to its
final value. The GATE-to-SENSE clamp limits the maxi-
mum ∆VGATEto 18V.
Board RemovalIf the circuit card is removed from the backplane, the volt-
age at the UV falls below the UVLO detect threshold, and
the MAX5921/MAX5939 turn off the external MOSFET.
Current Limit and Electronic Circuit
BreakerThe MAX5921/MAX5939 provide current-limiting and cir-
cuit-breaker features that protect against excessive load
current and short-circuit conditions. The load current is
monitored by sensing the voltage across an external
sense resistor connected between VEEand SENSE.
MAX5921
MAX5939
VEE
SENSEGATEDRAIN
PWRGD
VDD
-48V RTN
-48V RTN
SHORT PIN
VIN+
VIN-
VICOR
VI-J3D-CY
-48V
GATE IN
100μF
100V
0.1μF
100V
15nF
100V
1kΩ
10Ω
IRF530
0.02Ω
549kΩ
6.49kΩ
10kΩ
4.7nF
Figure 6a. Inrush Control Circuitry/Typical Application Circuit
