General Description
The MAX5933A–MAX5933F/MAX5947A/B/C fully integrat-
ed hot-swap controllers for +9V to +80V positive supply
rails (MAX5947A/B/C), allow for the safe insertion and
removal of circuit cards into live backplanes without caus-
ing glitches on the backplane power-supply rail. The
MAX5947B is pin- and function-compatible with the
LT1641-2. The other devices offer added features such
as a choice of active-high or active-low power-good out-
puts (PWRGD/PWRGD), latched/autoretry fault manage-
ment, and autoretry duty-cycle options of 3.75% or 0.94%
(see the Selector Guide).
The MAX5933A–MAX5933F are available with a default
undervoltage lockout threshold of +31V and operate over
a supply voltage range of +33V to +80V. The
MAX5947A/B/C are available with a default undervoltage
of +8.3V. All devices feature a programmable analog
foldback current limit. If the device remains in current limit
for more than a programmable time, the external
n-channel MOSFET is either latched off (MAX5933A/
MAX5933C/MAX5947A) or is set to automatically restart
after a timeout delay (MAX5933B/MAX5933D/MAX5933E/
MAX5933F/MAX5947B/MAX5947C).
The MAX5933_ and MAX5947_ operate in the extended
temperature range of -40°C to +85°C. These devices are
available in an 8-pin SO package.
Applications
Hot Board Insertion
Electronic Circuit Breakers
Industrial High-Side Switch/Circuit Breakers
Network Routers and Switches
24V/48V Industrial/Alarm Systems
Features
Pin- and Function-Compatible with the LT1641-2
(MAX5947B)
Provides Safe Hot Swap for +9V to +80V Power-
Supply Range (MAX5947A/B/C)
Safe Board Insertion and Removal from Live
Backplanes
Latched/Autoretry Management
Active-Low or Active-High Power-Good Output
Programmable Foldback Current Limiting
High-Side Drive for an External N-Channel MOSFET
Built-In Thermal Shutdown
Undervoltage Lockout (UVLO)
Overvoltage Protection
User-Programmable Supply Voltage
Power-Up Rate
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3263; Rev 1; 7/04
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.
Typical Application Circuit and Pin Configuration appear at
end of data sheet.
PART TEMP RANGE PIN-PACKAGE
MAX5933_ESA* -40°C to +85°C 8 SO
MAX5947_ESA* -40°C to +85°C 8 SO
*Insert the desired suffix from the Selector Guide into the blank
to complete the part number.
PART
LATCHED
FAULT
PROTECTION
AUTORETRY
FAULT
PROTECTION
PWRGD
OUTPUT LOGIC
DUTY CYCLE
(%)
DEFAULT UVLO
(V)
SUPPLY
VOLTAGE
RANGE (V)
MAX5933A Yes High 31 33 to 80
MAX5933B Yes High 3.75 31 33 to 80
MAX5933C Yes Low 31 33 to 80
MAX5933D Yes Low 3.75 31 33 to 80
MAX5933E Yes High 0.94 31 33 to 80
MAX5933F Yes Low 0.94 31 33 to 80
MAX5947A Yes Low 8.3 9 to 80
MAX5947B Yes High 3.75 8.3 9 to 80
MAX5947C Yes Low 3.75 8.3 9 to 80
Selector Guide
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = +24V (MAX5947A/B/C), VCC = +48V (MAX5933A–MAX5933F), GND = 0V, TA= -40°C to +85°C, unless otherwise noted.
Typical values are at TA= +25°C.) (Note 1)
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.
(Voltages Referenced to GND)
VCC .........................................................................-0.3V to +85V
SENSE, FB, ON ..........................................-0.3V to (VCC + 0.3V)
TIMER, PWRGD, PWRGD.......................................-0.3V to +85V
GATE ......................................................................-0.3V to +95V
Maximum GATE Current ....................................-50mA, +150mA
Maximum Current into Any Other Pin................................±50mA
Continuous Power Dissipation (TA= +70°C)
8-Pin SO (derate 5.9mW/°C above +70°C)..................470mW
Operating Temperature Range ...........................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ESD Rating (Human Body Model)......................................2000V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX5947A/B/C 9 80
Supply Voltage Range VCC MAX5933A–MAX5933F 33 80
V
Supply Current ICC VON = 3V, VCC = 80V 1.4 3.5 mA
MAX5947A/B/C 7.5 8.3 8.8
VCC Undervoltage Lockout VLKO VCC low-to-high
transition MAX5933A–MAX5933F 29.5 31 32.5
V
MAX5947A/B/C 0.4
VCC Undervoltage Lockout
Hysteresis VLKOHYST MAX5933A–MAX5933F 2 V
FB High-Voltage Threshold VFBH FB low-to-high transition 1.280 1.313 1.345 V
FB Low-Voltage Threshold VFBL FB high-to-low transition 1.221 1.233 1.245 V
FB Hysteresis VFBHYST 80 mV
FB Input Bias Current IINFB VFB = 0V -1 +1 µA
FB Threshold Line Regulation VFB VCC(MIN) VCC 80V, ON = 0V,
TA = 0°C to +70°C 0.05 mV/V
VFB = 0V, TA = 0°C to +70°C 8 12 17
SENSE Trip Voltage
(VCC - VSENSE)VSENSETRIP VFB = 1V, TA = 0°C to +70°C 39 47 55 mV
GATE Pullup Current IGATEUP Charge pump on, VGATE = 7V -5 -10 -20 µA
GATE Pulldown Current IGATEDN Any fault condition, VGATE = 2V 35 70 100 mA
MAX5933A–MAX5933F 10 13.6 18
VCC = 10.8V to 20V,
MAX5947A/B/C 4.5 6.2 18.0
External N-Channel Gate Drive VGATE VGATE - VCC
VCC = 20V to 80V,
MAX5947A/B/C 10 13.2 18
V
TIMER Pullup Current ITIMERUP VTIMER = 0V -24 -80 -120 µA
MAX5933A–MAX5933D,
MAX5947A/B/C 1.5 3 4.5
TIMER Pulldown Current ITIMERON VTIMER = 1V
MAX5933E/MAX5933F 0.37 0.75 1.12
µA
ON Logic-High Threshold VONH ON low-to-high transition 1.280 1.313 1.345 V
ON Logic-Low Threshold VONL ON high-to-low transition 1.221 1.233 1.245 V
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
_______________________________________________________________________________________ 3
Note 1: All currents into the device are positive and all currents out of the device are negative. All voltages are referenced to
ground, unless otherwise noted.
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +24V (MAX5947A/B/C), VCC = +48V (MAX5933A–MAX5933F), GND = 0V, TA= -40°C to +85°C, unless otherwise noted.
Typical values are at TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
ON Hysteresis VONHYST 80 mV
ON Input Bias Current IINON VON = 0V -1 +1 µA
PWRGD Leakage Current IOH VPWRGD = 80V 10 µA
PWRGD Leakage Current IOL VPWRGD = 80V 10 µA
IO = 2mA 0.4
PWRGD/PWRGD Output Low
Voltage IO = 4mA 2.5 V
SENSE Input Bias Current ISENSE VSENSE = 0V to VCC -1 +3 µA
Thermal Shutdown Temperature rising +150 °C
Thermal Shutdown Hysteresis 20 °C
ON Low-to-GATE Low
Propagation Delay tPHLON CGATE = 0, Figures 1, 2 6 µs
ON High-to-GATE High
Propagation Delay tPLHON CGATE = 0, Figures 1, 2 1.7 µs
FB Low-to-PWRGD Low
Propagation Delay tPHLFB Figures 1, 3 3.2 µs
FB High-to-PWRGD High
Propagation Delay tPLHFB Figures 1, 3 1.5 µs
(VCC - VSENSE) High-to-GATE
Low Propagation Delay tPHLSENSE TA = +25°C, CGATE = 0, Figures 1, 4 0.5 2 µs
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
4 _______________________________________________________________________________________
Test Circuit and Timing Diagrams
MAX5933_
MAX5947_
ON VCC
24V
SENSE
GATE
TIMER
FB
PWRGD
GND
5k
V+ = 5V
10nF
Figure 1. Test Circuit
ON
GATE
1.313V 1.233V
5V 1V
tPHLON
tPLHON
Figure 2. ON to GATE Timing
FB
PWRGD
1.313V
1V
1.233V
1V
tPLHFB tPHLFB
Figure 3. FB to PWRGD Timing
VCC - SENSE
GATE
47mV
VCC
tPHLSENSE
Figure 4. SENSE to GATE Timing
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
_______________________________________________________________________________________ 5
ICC vs. VCC
MAX5933 toc01
VCC (V)
ICC (mA)
0.3
0.6
0.9
1.2
1.5
1.8
2.1
2.4
2.7
0
726456484033 80
TA = -40°C
TA = +25°CTA = +85°C
ICC vs. TEMPERATURE
MAX5933 toc02
TEMPERATURE (°C)
ICC (mA)
603510-15
0.5
1.0
1.5
2.0
2.5
3.0
0
-40 85
VCC = 48V (MAX5933_/MAX5947_)
VCC = 24V (MAX5947_)
FB LOW-VOLTAGE THRESHOLD
vs. TEMPERATURE
MAX5933 toc03
TEMPERATURE (°C)
FB LOW-VOLTAGE THRESHOLD (V)
603510-15
1.205
1.210
1.215
1.220
1.225
1.230
1.235
1.240
1.245
1.250
1.200
-40 85
FB HIGH-VOLTAGE THRESHOLD
vs. TEMPERATURE
MAX5933 toc04
TEMPERATURE (°C)
FB HIGH-VOLTAGE THRESHOLD (V)
603510-15-40 85
1.285
1.290
1.295
1.300
1.305
1.310
1.315
1.320
1.325
1.330
1.335
1.280
FB HYSTERESIS vs. TEMPERATURE
MAX5933 toc05
TEMPERATURE (°C)
FB HYSTERESIS (V)
603510-15
0.05
0.06
0.07
0.08
0.09
0.10
0.11
0.04
-40 85
IGATE PULLUP CURRENT
vs. TEMPERATURE
MAX5933 toc06
TEMPERATURE (°C)
IGATE PULLUP CURRENT (µA)
6035-15 10
-12
-11
-10
-9
-7
-8
-6
-5
-13
-40 85
MAX5947_
GATE DRIVE vs. VCC
MAX5933 toc08
VCC (V)
GATE DRIVE (VGATE - VCC) (V)
6050 704020 3010
2
4
6
8
10
12
14
16
0
080
GATE DRIVE vs. TEMPERATURE
MAX5933 toc07
TEMPERATURE (°C)
GATE DRIVE (VGATE - VCC) (V)
603510-15
6
7
8
9
10
11
12
13
14
15
5
-40 85
VCC = 48V (MAX5933_/MAX5947_)
VCC = 10.8V (MAX5947_)
Typical Operating Characteristics
(VCC = +48V, TA= +25°C, unless otherwise noted.)
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VCC = +48V, TA= +25°C, unless otherwise noted.)
TIMER PULLUP CURRENT
vs. TEMPERATURE
MAX5933 toc09
TEMPERATURE (°C)
TIMER PULLUP CURRENT (µA)
603510-15
-85
-80
-75
-70
-65
-60
-90
-40 85
MAX5933_
TIMER PULLUP CURRENT vs. VCC
MAX5933 toc10
VCC (V)
TIMER PULLUP CURRENT (µA)
-78
-77
-76
-75
-74
-73
-79
40 50 60 7030 80
TA = +25°CTA = +85°C
TA = -40°C
TA = 0°C
MAX5947_
TIMER PULLUP CURRENT vs. VCC
MAX5933 toc11
VCC (V)
TIMER PULLUP CURRENT (µA)
70605040302010
-78
-77
-76
-75
-74
-73
-79
080
TA = +25°CTA = +85°C
TA = -40°C
TA = 0°C
ON HIGH-VOLTAGE THRESHOLD
vs. TEMPERATURE
MAX5933 toc12
TEMPERATURE (°C)
ON HIGH-VOLTAGE THRESHOLD (V)
603510-15
1.293
1.303
1.313
1.323
1.333
1.343
1.283
-40 85
ON LOW-VOLTAGE THRESHOLD
vs. TEMPERATURE
MAX5933 toc13
TEMPERATURE (°C)
ON LOW-VOLTAGE THRESHOLD (V)
603510-15
1.215
1.225
1.235
1.245
1.255
1.265
1.205
-40 85
ON HYSTERESIS vs. TEMPERATURE
MAX5933 toc14
TEMPERATURE (°C)
ON HYSTERESIS (V)
603510-15
0.075
0.077
0.079
0.081
0.083
0.073
-40 85
SENSE REGULATION VOLTAGE vs. VFB
MAX5933 toc16
VFB (V)
SENSE REGULATION VOLTAGE (mV)
0.80.60.40.2
5
10
15
20
25
30
35
40
45
50
0
0 1.0
PWRGD VOUT LOW vs. ILOAD
MAX5933 toc15
ILOAD (mA)
PWRGD VOUT LOW (V)
705030
2
4
6
8
10
12
14
16
18
20
0
10 90
TA = +85°CTA = +25°CTA = -40°C
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
_______________________________________________________________________________________ 7
Pin Description
PIN NAME FUNCTION
1ON
ON/OFF Control Input. ON is used to implement the undervoltage lockout threshold and resets the part
after a fault condition for the latched-off version (MAX5933A/MAX5933C/MAX5947A, see the Detailed
Description section).
2FB
Power-Good Comparator Input. Connect a resistive divider from output to FB to GND to monitor the output
voltage (see the Power-Good Detection section). FB is also used as a feedback for the current-limit
foldback function.
3PWRGD/
PWRGD
Open-Drain Power-Good Output. PWRGD is high (PWRGD is low) when VFB is higher than VFBH. PWRGD
is low (PWRGD is high) when VFB is lower than VFBL.
4 GND Ground
5 TIMER Timing Input. Connect a capacitor from TIMER to GND to program the maximum time the part is allowed to
remain in current limit (see the TIMER section).
6 GATE Gate- D r i ve O utp ut. The hi g h- si d e g ate d r i ve for the exter nal N - channel M OS FE T ( see the G ATE V ol tag e secti on) .
7 SENSE Current-Sense Input. Connect a sense resistor from VCC to SENSE and the drain of the external n-channel
MOSFET.
8V
CC Power-Supply Input. Bypass VCC to GND with a 0.1µF capacitor. Input voltage range is from +9V to +80V
for the MAX5947A/B/C. Input voltage range is from +33V to +80V for the MAX5933A–MAX5933F.
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
8 _______________________________________________________________________________________
Functional Diagram
MAX5933_
MAX5947_
VP GEN
OPEN
DRAIN
1.233V
1.233V
SENSEVCC
FB
GATE
PWRGD
(PWRGD)
ON
TIMER
CHARGE
PUMP
AND
GATE
DRIVER
REF
GEN
VCC
0.5V
VP
80µA
GND
LOGIC
VUVLO
0.5V
3µA
*0.75µA
UNDERVOLTAGE
LOCKOUT
12mV TO 47mV
( ) FOR THE MAX5933C/D/F AND THE MAX5947A/C.
*FOR THE MAX5933E/MAX5933F.
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
_______________________________________________________________________________________ 9
Detailed Description
The MAX5933_ and MAX5947_ are fully integrated hot-
swap controllers for positive supply rails. The devices
allow for the safe insertion and removal of circuit cards
into live backplanes without causing glitches on the
backplane power-supply rail. During startup, the
MAX5933_ and MAX5947_ act as current regulators
using an external sense resistor and a MOSFET to limit
the amount of current drawn by the load.
The MAX5933_ operate from a +33V to +80V supply
voltage range and have a default undervoltage lockout
(UVLO) set to +31V. The MAX5947_ operate from a
+9V to +80V supply voltage range and have a default
UVLO set to +8.3V. The UVLO threshold is adjustable
using a resistive divider connected from VCC to ON to
GND (see Figure 5).
The MAX5933_ and MAX5947_ monitor the input volt-
age, the output voltage, the output current, and the die
temperature. These devices feature power-good outputs
(PWRGD/PWRGD) to indicate the status of the output
voltage by monitoring the voltage at FB (see the Power-
Good Detection section).
As shown in Figure 5, a sense resistor is connected
between VCC and SENSE to regulate the voltage
across the sense resistor (VIN - VSENSE) to 47mV when
the voltage at FB 0.5V. The current-limit threshold
(VSENSETRIP) decreases linearly from 47mV to 12mV as
FB decreases from 0.5V to 0V.
An undervoltage fault is detected when ON goes below
the threshold (VONL = 1.233V) and the voltage at GATE
goes low as a result to turn off the MOSFET. ON must
pass the VONH = 1.313V threshold to turn on the
MOSFET again.
R6
1k
5%
C1
10nF
D1
CMPZ5248B
Q1
IRF530
R5
10
5%
RSENSE
0.025
R3
59k
1%
R4
3.57k
1%
R7
24k
5%
CL
R2
3.4k
1%
R1
49.9k
1%
C2
0.68µF
MAX5933A
PWRGD
GND
VIN
24V
TIMER
ON
PWRGD
FB
GND
VCC SENSE GATE
5
1
3
2
4
876
0.1µF
Figure 5. Application Circuit
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
10 ______________________________________________________________________________________
Applications Information
Hot-Circuit Insertion
When circuit boards are inserted into a live backplane,
the supply bypass capacitors on the boards draw high
peak currents from the backplane power bus as they
charge up. The transient currents can permanently
damage the connector pins and glitch the system sup-
ply, causing other boards in the system to reset.
Power-Up Sequence
The power supply on a board is controlled by placing
an external n-channel MOSFET (Q1) in the power path
(Figure 5). Resistor RSENSE provides current detection
and capacitor C1 provides control of the GATE slew
rate. Resistor R6 provides current control-loop compen-
sation, while R5 prevents high-frequency oscillations in
Q1. Resistors R1 and R2 provide undervoltage sensing.
After the power pins first make contact, transistor Q1 is
turned off. When the voltage at ON exceeds the turn-on
threshold voltage, the voltage on VCC exceeds the
undervoltage lockout threshold, and when the voltage
on TIMER is less than 1.233V, transistor Q1 turns on
(Figure 6).
The voltage at GATE rises with a slope equal to
10µA/C1 and the supply inrush current is set at:
IINRUSH = CLx 10µA/C1
When the voltage across the current-sense resistor
RSENSE reaches VSENSETRIP, the inrush current is limit-
ed by the internal current-limit circuitry that adjusts the
voltage on GATE to maintain a constant voltage across
the sense resistor.
Once the voltage at the output has reached its final value,
as sensed by resistors R3 and R4, PWRGD goes high or
PWRGD goes low.
Short-Circuit Protection
The MAX5933_/MAX5947_ feature a programmable fold-
back current limit with an electronic circuit breaker that
protects against short circuits or excessive supply cur-
rents. The current limit is set by placing a sense resistor
between VCC (pin 8) and SENSE (pin 7).
To prevent excessive power dissipation in the pass
transistor and to prevent voltage spikes on the input
supply during short-circuit conditions at the output, the
current folds back as a function of the output voltage
that is sensed at FB (Figure 7).
When the voltage at FB is 0V, the current-limit circuit
drives GATE to force a constant 12mV drop across the
sense resistor. As the output voltage at FB increases,
the voltage across the sense resistor increases until FB
reaches 0.5V. At this point, the voltage across the
sense resistor is held constant at 47mV.
The maximum current limit is calculated as:
ILIMIT = 47mV / RSENSE
For a 0.025sense resistor, the current limit is set at
1.88A and folds back to 480mA when the output is
shorted to ground.
The MAX5933_/MAX5947_ also feature a variable over-
current response time. The time required to regulate
Q1’s drain current depends on:
1) Q1’s input capacitance
2) GATE capacitor C1 and compensation resistor R6
3) The internal delay from SENSE to GATE
Figure 8 shows the delay from a voltage step at SENSE
until GATE voltage starts falling, as a function of
overdrive.
POWER-UP WAVEFORMS
ISENSE
2A/div
PWRGD
50V/div
OUTPUT
50V/div
GATE
50V/div
20ms/div
Figure 6. Power-Up Waveforms
VCC - VSENSE
VFB
12mV
47mV
0.5V0V
Figure 7. Current-Limit Sense Voltage vs. Feedback Voltage
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
______________________________________________________________________________________ 11
TIMER
TIMER provides a method for programming the maxi-
mum time the device is allowed to operate in current
limit. When the current-limit circuitry is not active,
TIMER is pulled to GND by a 3µA current source. After
the current-limit circuit becomes active, an 80µA pullup
current source is connected to TIMER, and the voltage
rises with a slope equal to 77µA/CTIMER, as long as the
current-limit circuit remains active. Once the desired
maximum current-limit time is chosen, the capacitor
value is:
C(nF) = 65 x t(ms)
or
TLIMIT = (CTIMER/80µA) x 1.233V
When the current-limit circuit turns off, TIMER is dis-
charged to GND by the 3µA current source.
Whenever TIMER reaches 1.233V, the internal fault
latch is set. GATE is immediately pulled to GND and
TIMER is pulled back to GND by the 3µA current
source. When TIMER falls below 0.5V, ON is pulsed low
to reset the internal fault latch.
The waveform in Figure 9 shows how the output latches
off following a short circuit. The drop across the sense
resistor is held at 12mV as the timer ramps up. Since
the output did not rise, FB remains below 0.5V and the
circuit latches off. For Figure 9, CT= 100nF.
Undervoltage and Overvoltage Detection
ON can be used to detect an undervoltage condition at
the power-supply input. ON is internally connected to
an analog comparator with 80mV of hysteresis. If ON
falls below its threshold voltage (1.233V), GATE is
pulled low and is held low until ON is high again.
Figure 10 shows an overvoltage detection circuit. When
the input voltage exceeds the Zener diode’s breakdown
voltage, D1 turns on and starts to pull TIMER high. After
TIMER is pulled higher than 1.233V, the fault latch is set
and GATE is pulled to GND immediately, turning off
transistor Q1 (see Figure 11). Operation is restored
either by interrupting power or by pulsing ON low.
Power-Good Detection
The MAX5933_/MAX5947_ include a comparator for mon-
itoring the output voltage. The noninverting input (FB) is
compared against an internal 1.233V precision reference
and exhibits 80mV hysteresis. The comparator’s output
(PWRGD) is open drain and capable of operating from a
pullup as high as 80V. The PWRGD is similar to PWRGD
with an opposite polarity (active low) output.
The PWRGD (PWRGD) can be used to directly
enable/disable a power module with an active-high
enable input. Figure 12 shows how to use PWRGD to
control an active-low enable-input power module. Signal
inversion is accomplished by transistor Q2 and R7.
Supply Transient Protection
The MAX5933_/MAX5947_ are 100% tested and guar-
anteed to be safe from damage with supply voltages
up to 80V. However, spikes above 85V may damage
the device. During a short-circuit condition, the large
change in currents flowing through the power-supply
traces can cause inductive voltage spikes which could
exceed 85V. To minimize the spikes, the power-trace
parasitic inductance should be minimized by using
wider traces or heavier trace plating and a 0.1µF
bypass capacitor placed between VCC and GND. A
transient voltage suppressor (TVS) at the input can also
prevent damage from voltage surges.
RESPONSE TIME TO OVERCURRENT
VCC - VSENSE (mV)
PROPAGATION DELAY (µs)
200100
2
4
6
8
10
12
14
0
0300
Figure 8. Response Time to Overcurrent
SHORT-CIRCUIT WAVEFORMS
ISENSE
1A/div
TIMER
1V/div
OUTPUT
50V/div
GATE
50V/div
10ms/div
Figure 9. Short-Circuit Waveforms
GATE Voltage
A curve of Gate Drive vs. VCC is shown in Figure 13.
GATE is clamped to a maximum voltage of 18V above the
input voltage. At a minimum input-supply voltage of 33V,
the minimum gate drive voltage is 10V. When the input
supply voltage is higher than 20V, the gate-drive voltage
is at least 10V and a standard n-channel MOSFET can be
used. Using the MAX5947 in applications over a 9V to
20V range, a logic-level N-FET must be used with a prop-
er protection Zener diode between its gate and source
(see D1 in Figure 5).
Thermal Shutdown
If the MAX5933_/MAX5947_ die temperature reaches
+150°C, an overtemperature fault is generated. As a
result, GATE goes low and turns the external MOSFET off.
The MAX5933_/MAX5947_ die temperature must cool
down below +130°C before the overtemperature fault
condition is removed.
R6
1k
5%
C1
10nF
D2
CMPZ5248B
Q1
IRF530
R5
10
5%
RSENSE
0.025
R3
59k
1%
R4
3.57k
1%
R7
24k
5%
CL
R2
3.4k
1%
R1
49.9k
1%
C2
0.68µF
MAX5933B
MAX5947B
PWRGD
GND
VIN
TIMER
ON
PWRGD
FB
GND
VCC SENSE GATE
5
1
3
2
4
876
D1
30V
1N5256B
SHORT
PIN
0.1µF
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
12 ______________________________________________________________________________________
OVERVOLTAGE WAVEFORMS
ISENSE
5A/div
TIMER
10V/div
IN
50V/div
GATE
50V/div
10µs/div
OUTPUT
50V/div
Figure 11. Overvoltage Waveforms
Figure 10. Overvoltage Detection
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
______________________________________________________________________________________ 13
Layout Considerations
To achieve accurate current sensing, a Kelvin connec-
tion is recommended. The minimum trace width for 1oz
copper foil is 0.02in per amplifier to ensure the trace
stays at a reasonable temperature. However, 0.03in.
per amplifier or wider is recommended. Note that 1oz
copper exhibits a sheet resistance of approximately
530µ/square. Small resistances add up quickly in
high-current applications. To improve noise immunity,
connect the resistor-divider to ON close to the device,
and keep traces to VCC and GND short. A 0.1µF
capacitor from ON to GND also helps reject induced
noise. Figure 14 shows a layout that addresses these
issues. It is recommended that 2oz copper is used,
particularly as the external MOSFET must be thermally
coupled to the MAX5933_/MAX5947_ to ensure proper
thermal-shutdown operation.
R6
1k
5%
C1
10nF
D1
CMPZ5248B
Q1
IRF530
R5
10
5%
RSENSE
0.01
R3
143k
1%
R4
4.22k
1%
R7
47k
5%
CL
220µF
R2
10.2k
1%
R1
294k
1%
C2
0.68µF
MAX5933A
GND
VIN
TIMER
ON
PWRGD
FB
GND
VCC SENSE GATE
5
1
3
2
4
876
SHORT
PIN
VIN+
ON/OFF
VIN-
VOUT+
VOUT-
VOUT
0.1µF
GATE DRIVE vs. VCC
VCC (V)
GATE DRIVE (VGATE - VCC) (V)
604020
2
4
6
8
10
12
14
16
0
080
Figure 13. Gate Drive vs. Supply Voltage
Figure 12. Active-Low Enable Module
Typical Application Circuit
R6
1k
5%
C1
10nF
D1
CMPZ5248B
Q1
IRF530
R5
10
5%
RSENSE
0.01
R3
59k
1%
R4
3.57k
1%
R7
24k
5%
CL
R2
3.4k
1%
R1
49.9k
1%
C2
0.68µF
MAX5933A
PWRGD
GND
VIN
TIMER
ON
PWRGD
FB
GND
VCC SENSE GATE
5
1
3
2
4
876
*SMBJ51A
*DIODES, INC.
0.1µF
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
14 ______________________________________________________________________________________
Chip Information
TRANSISTOR COUNT: 1573
PROCESS: BiCMOS
IRF530
MAX5933_
MAX5947_
Figure 14. Recommended Layout for R1, R2, and RSENSE
GATE
TIMERGND
1
2
8
7
VCC
SENSEFB
PWRGD (PWRGD)
ON
SO
TOP VIEW
3
4
6
5
MAX5933_
MAX5947_
( ) ONLY FOR THE MAX5933C/D/F/MAX5947A/MAX5947C.
Pin Configuration
MAX5933A–MAX5933F/MAX5947A/B/C
Positive High-Voltage, Hot-Swap Controllers
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15
© 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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.)
SOICN .EPS
PACKAGE OUTLINE, .150" SOIC
1
1
21-0041 B
REV.DOCUMENT CONTROL NO.APPROVAL
PROPRIETARY INFORMATION
TITLE:
TOP VIEW
FRONT VIEW
MAX
0.010
0.069
0.019
0.157
0.010
INCHES
0.150
0.007
E
C
DIM
0.014
0.004
B
A1
MIN
0.053A
0.19
3.80 4.00
0.25
MILLIMETERS
0.10
0.35
1.35
MIN
0.49
0.25
MAX
1.75
0.050
0.016L0.40 1.27
0.3940.386D
D
MINDIM
D
INCHES
MAX
9.80 10.00
MILLIMETERS
MIN MAX
16 AC
0.337 0.344 AB8.758.55 14
0.189 0.197 AA5.004.80 8
N MS012
N
SIDE VIEW
H 0.2440.228 5.80 6.20
e 0.050 BSC 1.27 BSC
C
HE
eBA1
A
D
0∞-8∞
L
1
VARIATIONS: