Datasheet

12 Maxim Integrated
Active-Clamped, Spread-Spectrum,
Current-Mode PWM Controllers
MAX5974A/MAX5974B/MAX5974C/MAX5974D
Pin Configuration
Pin Description
15
16
14
13
5
6
7
RT
FFB
8
DT
PGND CS AUXDRV
13
EN
4
12 10 9
DCLMP
SS
CSSC
GND
FB
COMP
EP
MAX5974A
MAX5974B
MAX5974C
MAX5974D
DITHER/
SYNC
NDRV
2
11
IN
THIN QFN
TOP VIEW
+
PIN NAME FUNCTION
1 DT
Dead-Time Programming Resistor Connection. Connect resistor R
DT
from DT to GND to set the
desired dead time between the NDRV and AUXDRV signals. See the Dead Time section to calculate
the resistor value for a particular dead time.
2
DITHER/
SYNC
Frequency Dithering Programming or Synchronization Connection. For spread-spectrum frequency
operation, connect a capacitor from DITHER to GND and a resistor from DITHER to RT. To
synchronize the internal oscillator to the externally applied frequency, connect DITHER/SYNC to the
synchronization pulse.
3 RT
Switching Frequency Programming Resistor Connection. Connect resistor R
RT
from RT to GND to
set the PWM switching frequency. See the Oscillator/Switching Frequency section to calculate the
resistor value for the desired oscillator frequency.
4 FFB
Frequency Foldback Threshold Programming Input. Connect a resistor from FFB to GND to set the
output average current threshold below which the converter folds back the switching frequency to
1/2 of its original value. Connect to GND to disable frequency foldback.
5 COMP
Transconductance Amplifier Output and PWM Comparator Input. COMP is level shifted down
and connected to the inverting input of the PWM comparator. COMP is actively pulled low by the
controller after shutdown.