Datasheet

3Maxim Integrated
Active-Clamped, Spread-Spectrum,
Current-Mode PWM Controllers
MAX5974A/MAX5974B/MAX5974C/MAX5974D
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 12V (for MAX5974A/MAX5974C, bring V
IN
up to 17V for startup), V
CS
= V
CSSC
= V
DITHER/SYNC
= V
FB
= V
FFB
= V
DCLMP
=
V
GND
, V
EN
= +2V, NDRV = AUXDRV = SS = COMP = unconnected, R
RT
= 34.8kI, R
DT
= 25kI, C
IN
= 1FF, T
A
= -40NC to +85NC,
unless otherwise noted. Typical values are at T
A
= +25NC.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
ENABLE (EN)
Enable Threshold
V
ENR
V
EN
rising
-40°C to +85°C 1.17 1.215 1.26
V
-40°C to +125°C
1.17 1.2155 1.2655
V
ENF
V
EN
falling
-40°C to +85°C 1.09 1.14 1.19
-40°C to +125°C 1.085 1.14 1.19
Input Current I
EN
1 FA
OSCILLATOR (RT)
RT Bias Voltage V
RT
1.23 V
NDRV Switching Frequency
Range
f
SW
100 600 kHz
NDRV Switching Frequency
Accuracy
-8 +8 %
Maximum Duty Cycle
D
MAX
f
SW
= 250kHz
-40°C to +85°C 79 80 82
%
-40°C to +125°C 79 80 83
SYNCHRONIZATION (SYNC)
Synchronization Logic-High
Input
V
IH-SYNC
2.91 V
Synchronization Pulse Width 50 ns
Synchronization Frequency
Range
f
SYNCIN
1.1 x
f
SW
2 x
f
SW
kHz
Maximum Duty Cycle During
Synchronization
D
MAX
x f
SYNC
/
f
SW
%
DITHERING RAMP GENERATOR (DITHER)
Charging Current V
DITHER
= 0V
-40°C to +85°C 45 50 55
FA
-40°C to +125°C 44.5 50 55.5
Discharging Current V
DITHER
= 2.2V
-40°C to +85°C 43 50 57
FA
-40°C to +125°C 42 50 58
Ramp’s High Trip Point 2 V
Ramp’s Low Trip Point 0.4 V