MAX5949BESA ,-48V Hot-Swap Controllers with External RSENSEELECTRICAL CHARACTERISTICS(V = 0V, V = 48V, T = -40°C to +85°C. Typical values are at T = +25°C, un ..
MAX5949BESA+ ,-48V Hot-Swap Controllers with External RSENSEFeaturesThe MAX5949A/MAX5949B are hot-swap controllers that♦ Allow Safe Board Insertion and Removal ..
MAX5952AEAX+ ,High-Power, Quad, PSE Controller for Power-Over-EthernetApplicationsPower-Sourcing Equipment (PSE)Switches/RoutersMidspan Power InjectorsPin Configuration ..
MAX5952AEAX+T ,High-Power, Quad, PSE Controller for Power-Over-EthernetELECTRICAL CHARACTERISTICS (V = 32V to 60V, V = 0V, V to V = +3.3V, all voltages are referenced to ..
MAX5952AUAX+ ,High-Power, Quad, PSE Controller for Power-Over-Ethernetapplications.♦ Open-Drain INT SignalThe MAX5952 provides four operating modes to suit dif-ferent sy ..
MAX5954LETX+ ,Single PCI Express, Hot-Plug Controllerapplications. The device provides hot-plug♦ Hot Swaps 12V, 3.3V, and 3.3V Auxiliary for a control f ..
MAZ8160-H ,Silicon planar typeElectrical Characteristics T = 25°CaParameter Symbol Conditions Min Typ Max UnitForward voltage V ..
MAZ8160-L ,Silicon planar typeZener DiodesMAZ8000 SeriesSilicon planar typeUnit : mmFor stabilization of power supplyKA
MAZ8160-M ,Silicon planar typeelectrical characteristicsZ Zwithin part numbersReverse current I V ··············· Specified value ..
MAZ8180 ,Small-signal deviceAbsolute Maximum Ratings T = 25°CaMarking SymbolParameter Symbol Rating UnitRefer to the list of t ..
MAZ8180G ,Silicon planar typeFeatures Package Extremely low noise voltage caused from the diode (2.4 V to Code 39V, 1/3 to 1 ..
MAZ8180-H ,Silicon planar typeElectrical characteristics within part numbers T = 25°CaTemperaturecoefficient ofZener voltage Rev ..
MAX5949AESA-MAX5949BESA
-48V Hot-Swap Controllers with External RSENSE
General DescriptionThe MAX5949A/MAX5949B are hot-swap controllers that
allow a circuit card to be safely hot plugged into a live
backplane. The MAX5949A/MAX5949B operate from
-20V to -80V and are well-suited for -48V power systems.
These devices are pin and function compatible with the
LT4250 and pin compatible with the LT1640.
The MAX5949A/MAX5949B provide a controlled turn-on
to circuit cards preventing glitches on the power-supply
rail and damage to board connectors and components.
The MAX5949A/MAX5949B provide undervoltage, over-
voltage, and overcurrent protection. These devices
ensure the input voltage is stable and within tolerance
before applying power to the load.
Both the MAX5949A and MAX5949B 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 MAX5949A/MAX5949B also provide
protection against input voltage steps. During an input
voltage step, the MAX5949A/MAX5949B limit the cur-
rent drawn by the load to a safe level without turning off
power to the load.
Both devices feature an open-drain power-good status
output (PWRGDfor the MAX5949A or PWRGD for the
MAX5949B) that can be used to enable downstream
converters.
The MAX5949A/MAX5949B are available in an 8-pin SO
package. Both devices are specified for 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
Central-Office Switching
-48V Distributed Power Systems
Negative Power-Supply Controls
FeaturesAllow Safe Board Insertion and Removal
from a Live -48V BackplanePin and Function Compatible with LT4250L
(MAX5949A)Pin Compatible with LT1640L (MAX5949A)Pin and Function Compatible with LT4250H
(MAX5949B)Pin Compatible with LT1640H (MAX5949B)Circuit-Breaker Immunity to Input Voltage Steps
and Current SpikesWithstand -100V Input Transients with No
External ComponentsProgrammable Inrush and Short-Circuit Current
LimitsOperate from -20V to -80VProgrammable Overvoltage ProtectionProgrammable Undervoltage LockoutPower Up into a Shorted LoadPower-Good Control Output
MAX5949A/MAX5949B
-48V Hot-Swap Controllers
with External RSENSE
Pin Configuration
Ordering Information19-3494; Rev 0; 11/04
Typical Operating Circuit and Selector Guide appear at end
of data sheet.
MAX5949A/MAX5949B
-48V Hot-Swap Controllers
with External RSENSE
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VEE= 0V, VDD= 48V, TA= -40°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.) (Notes 2, 5)
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
PWRGD, PWRGD.................................................-0.3V to +100V
DRAIN (Note 1)........................................................-2V 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 Through SENSE...................................................±40mA
Current into GATE...........................................................±300mA
Current into DRAIN.........................................-100mA to +20mA
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
Note 1:Test condition per Figure 1. DRAIN current must be limited to the specified 100mA maximum.
MAX5949A/MAX5949B
-48V Hot-Swap Controllers
with External RSENSE
ELECTRICAL CHARACTERISTICS (continued)(VEE= 0V, VDD= 48V, TA= -40°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.) (Notes 2, 5)
unless otherwise specified.
Note 3:Current into VDDwith UV = 3V, OV = DRAIN = PWRGD = SENSE = VEE, GATE = floating.
Note 4:Minimum duration of GATE pulldown following a circuit-breaker fault. The circuit breaker can be reset during this time by
toggling UV low, but the GATE pulldown does not release until tOFFhas elapsed.
Note 5:Limits are 100% tested at TA= +25°C and +85°C. Limits at -40°C are guaranteed by design.
MAX5949A/MAX5949B
-48V Hot-Swap Controllers
with External RSENSE
Typical Operating Characteristics(VDD= 48V, VEE= 0V, TA = +25°C, unless otherwise noted.)
MAX5949A/MAX5949B
-48V Hot-Swap Controllers
with External RSENSEest CircuitsFigure 1. -2V DRAIN Voltage Test Circuit
Figure 2a. Test Circuit 1
Figure 2b. Test Circuit 2
MAX5949A/MAX5949B
-48V Hot-Swap Controllers
with External RSENSE
Timing DiagramsFigure 3. OV to GATE Timing
Figure 4. UV to GATE Timing
Figure 5a. SENSE to GATE Timing
Figure 5b. Active Current-Limit Threshold
MAX5949A/MAX5949B
-48V Hot-Swap Controllers
with External RSENSE
Timing Diagrams (continued)Figure 6a. DRAIN to PWRGD/PWRGD Timing
Figure 6b. GATE to PWRGD/PWRGD Timing
Block Diagram
MAX5949A/MAX5949B
Detailed DescriptionThe MAX5949A/MAX5949B are integrated hot-swap
controllers for -48V power systems. They 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 without
hot-swap control, the bypass capacitors at the input of
the board’s power module or switching power supply
can draw large inrush currents as they charge. The
inrush currents can cause glitches on the system
power-supply rail and damage components on the
board.
The MAX5949A/MAX5949B provide a controlled turn-on
to circuit cards, preventing glitches on the power-supply
rail and damage to board connectors and components.
Both the MAX5949A and MAX5949B provide undervolt-
age, overvoltage, and overcurrent protection. The
MAX5949A/MAX5949B ensure the input voltage is sta-
ble and within tolerance before applying power to the
load. The devices also provide protection against input
voltage steps. During an input voltage step, the
MAX5949A/MAX5949B limit the current drawn by the
load to a safe level without turning off power to the load.
-48V Hot-Swap Controllers
with External RSENSE
Board InsertionFigure7a 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 IVEE x Cgd /
(Cgd + Cgs)I. The MAX5949_ features 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 dynamic
clamp between GATE and VEEof the MAX5949A/
MAX5949B eliminates the need for an external gate-to-
source capacitor C1. Resistor R3 limits the current into
the clamp circuitry during card insertion.
Power-Supply RampingThe MAX5949_ can reside either on the backplane or
the removable circuit board (Figure 7a). Power is deliv-
ered to the load by placing an external n-channel
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 MAX5949_
turn on Q1. The MAX5949_ gradually turn on the exter-
nal MOSFET by charging the gate of Q1 with a 45µA
current source.
Capacitor C2 provides a feedback signal to accurately
limit the inrush current. The value of C2can be
calculated:
where CLis the total load capacitance, C3 + C4, and
IPUis the MAX5949_ gate pullup current.
Figure7b 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 VGSto about 18V under any condition.
Board RemovalIf the card is removed from a live backplane, the output
capacitor on the card may not be immediately dis-
charged. While the output capacitor is discharging, the
MAX5949_ continues to operate as if the input supply
were still connected because the output capacitor tem-
porarily supplies operating current to the IC. If the cir-
cuit is connected as in Figure 7a, the voltage at the UV
pin falls below the VUVL, and the MAX5949_ turns off
the external MOSFET. If R4 in the circuit is connected
directly to the -48V return, the external MOSFET
remains on until the capacitor is discharged sufficiently
to drop the UV pin voltage to VUVL.
MAX5949A/MAX5949B
-48V Hot-Swap Controllers
with External RSENSE
