Rainbow Electronics MAX17480 - Manual (Page 20)

MAX17480
AMD 2-/3-Output Mobile Serial
VID Controller
20 ______________________________________________________________________________________
Pin Description (continued)
PIN NAME FUNCTION
39 OSC
Oscillator Adjustment Input. Connect a resistor (R OSC ) between OSC and GND to set the switching
frequency (per phase):
f OSC = 300kHz x 143k /R
OSC
A 71.4k to 432k resistor corresponds to switching frequencies of 600kHz to 100kHz,
respectively, for SMPS1 and SMPS2. SMPS3 runs at twice the programmed switching frequency.
Switching frequency selection is limited by the minimum on-time. See the Core Switching
Frequency description in the SMPS Design Procedure section.
40 TIME
Slew-Rate Adjustment Pin. The total resistance R
TIME
from TIME to GND sets the internal slew rate:
PWM slew rate = (6.25mV/µs) x (143k /R
TIME )
where R TIME is between 35.7k and 357k.
This slew rate applies to both upward and downward VID transitions, and to the transition from boot
mode to VID mode. Downward VID transition slew rate in skip mode can appear slower because the
output transition is not forced by the SMPS.
The slew rate for startup is fixed at 1mV/µs.
EP PGND Exposed Pad. Power ground connection and source connection of the internal low-side MOSFET.