sc473mltrt Semtech Corporation, sc473mltrt Datasheet - Page 8

• Manufacturer Part Number: sc473mltrt
• Description: Sc473 Single-phase Single Chip Graphics Core Power Supply
• Manufacturer: Semtech Corporation

© 2006 Semtech Corp.
POWER MANAGEMENT
Pin Descriptions
Pin #
Pin Confi guration
10
12
13
14
15
16
17
18
19
20
21
22
23
24
11
1
2
3
4
5
6
7
8
9
Thermal Pad
SC473
Pin Name
ERROUT
PWRGD
CLSET
PMON
AGND
RAMP
VREF
VID4
VID3
VID2
VID1
VID0
DRN
HYS
FB+
CS+
BST
FB-
CS-
EN
BG
TG
SS
V5
VID most signifi cant bit
VID least signifi cant bit
Core comparator hysteresis - a resistor divider from VREF to AGND on this pin sets the
hysteresis voltage
Current limit set - a resistor divider from VREF to AGND on this pin sets the OCP threshold
Internal reference voltage (2V) - bypass to AGND with a 1000pF NPO ceramic capacitor
Quiet ground for analog control circuits
Error amplifi er compensation pin
Remote GND sense - connect to VSS_Sense at the CPU socket
Soft-start. The external NPO ceramic capacitor at this pin defi nes the soft-start ramp
Remote die sense of core voltage - connect to VCC_Sense at the CPU socket
Inverting input to Current-Sense amplifi er
Non-inverting input to Current-Sense amplifi er
An external R-C defi nes the internal slope ramp
Enable control pin - active high
Power good indicator, active high, open drain output
Power Monitor output
Input supply for both control circuits and gate drive. Connect to 5V and decouple with at least
1μF ox X5R ceramic capacitance
Output drive for the synchronous MOSFET
Inductor switching node - connect to the junction of the switching and synchronous
MOSEFETs
Output drive for the switching MOSFET
Bootstrap pin - a capacitor is connected between BST and DRN to develop the fl oating
voltage for the switching MOSFET
Power ground for driver - connect with at least two vias to the system GND plane
8
Pin Description
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SC473