Datasheet
MAX5941A/MAX5941B
IEEE 802.3af-Compliant Power-Over-Ethernet
Interface/PWM Controller for Power Devices
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (PWM Controller) (continued)
(All voltages referenced to V-. V
DD
= 13V, a 10µF capacitor connects V
CC
to V-, V
CS
= V-, V+ = 48V, 0.1µF capacitor connected to
SS_SHDN, NDRV = open circuit, OPTO = V-, T
A
= T
MIN
to +T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
V+ Shutdown Current V
SS_SHDN
= 0V, V+ = 67V
190
290 µA
V
DD
Shutdown Current V
SS_SHDN
= 0V 8 20 µA
PREREGULATORS/STARTUP
V+ Input Voltage 18 67 V
V
DD
Supply Voltage 13 36 V
INTERNAL REGULATORS
Powered from V+, I
CC
= 7.5mA, V
DD
= 0V 7.5 9.8 12
V
CC
Output Voltage
Powered from V
DD
, I
CC
= 7.5mA 9.0
10.0 11.0
V
V
CC
Undervoltage Lockout
V
CC_UVLO
V
CC
falling 6.6 V
OUTPUT DRIVER
Peak Source Current V
CC
= 11V (externally forced)
570
mA
Peak Sink Current V
CC
= 11V (externally forced)
1000
mA
NDRV High-Side Driver
Resistance
R
OH
V
CC
= 11V, externally forced, NDRV
sourcing 50mA
412 Ω
NDRV Low-Side Driver
Resistance
R
OL
V
CC
= 11V, externally forced, NDRV sinking
50mA
1.6 4 Ω
PWM COMPARATOR
OPTO Input Bias Current V
OPTO
= V
SS_SHDN
-1.00 +1.00
µA
OPTO Control Range 23V
Slope Compensation
V
SCOMP
MAX5941A 26
mV/µs
THERMAL SHUTDOWN
Thermal Shutdown Temperature 150
°C
Thermal Hysteresis 25 °C
CURRENT LIMIT
CS Threshold Voltage V
ILIM
V
OPTO
= 4V
419 465
510 mV
CS Input Bias Current 0V ≤ V
CS
≤ 2V, V
OPTO
= 4V -1 +1 µA
Current-Limit Comparator
Propagation Delay
25mV overdrive on CS, V
OPTO
= 4V
180
ns
CS Blanking Time V
OPTO
= 4V 70 ns
OSCILLATOR
Clock Frequency Range V
OPTO
= 4V
235 275
314 kHz
MAX5941A, V
OPTO
= 4V 75 85
Max Duty Cycle
MAX5941B, V
OPTO
= 4V 44 50
%
SOFT-START
SS Source Current I
SSO
V
SS(SHDN)
= 0V 2.0 4.6 6.5 µA
SS Sink Current 1mA
Peak Soft-Start Voltage Clamp No external load
2.331 2.420 2.500
V
V
SS_SHDN
falling (Note 11)
0.25 0.37 0.41
Shutdown Threshold
V
SS_SHDN
rising (Note 11)
0.53 0.59 0.65
V