ISL6277HRZ Datasheet, PDF (8/37 Pages) Intersil Corporation – Multiphase PWM Regulator for AMD Fusion™ Mobile CPUs Using SVI 2.0

ISL6277
Pin Descriptions (Continued)
PIN NUMBER
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
SYMBOL
ISEN1
ISUMP
ISUMN
VSEN
RTN
FB2
FB
COMP
PGOOD
BOOT1
UGATE1
PHASE1
LGATE1
PWM_Y
VDD
VDDP
LGATE2
PHASE2
UGATE2
BOOT2
VIN
BOOTX
DESCRIPTION
Individual current sensing for Channel 1 of the Core VR. If ISEN2 is tied to +5V, this pin cannot be left
open and must be tied to GND with a 10kΩ resistor. If ISEN1 is tied to +5V, the Core portion of the IC is
shut down.
Non-inverting input of the transconductance amplifier for current monitor and load line of Core output.
Inverting input of the transconductance amplifier for current monitor and load line of Core output.
Output voltage sense pin for the Core controller. Connect to the +sense pin of the microprocessor die.
Output voltage sense return pin for both Core VR and Northbridge VR. Connect to the -sense pin of the
microprocessor die.
There is a switch between the FB2 pin and the FB pin. The switch is on in 2-phase or 3-phase mode and
is off in 1-phase mode. The components connecting to FB2 are used to adjust the compensation in
1-phase mode of the Core VR to achieve optimum performance.
Output voltage feedback to the inverting input of the Core controller error amplifier.
Core controller error amplifier output. A resistor from COMP to GND sets the Core VR offset voltage.
Open-drain output to indicate the Core portion of the IC is ready to supply regulated voltage. Pull up
externally to VDD or 3.3V through a resistor.
Connect an MLCC capacitor across the BOOT1 and the PHASE1 pins. The boot capacitor is charged,
through an internal boot diode connected from the VDDP pin to the BOOT1 pin, each time the PHASE1
pin drops below VDDP minus the voltage dropped across the internal boot diode.
Output of the Phase 1 high-side MOSFET gate driver of the Core VR. Connect the UGATE1 pin to the gate
of the Phase 1 high-side MOSFET(s).
Current return path for the Phase 1 high-side MOSFET gate driver of VR1. Connect the PHASE1 pin to the
node consisting of the high-side MOSFET source, the low-side MOSFET drain, and the output inductor of
Phase 1.
Output of the Phase 1 low-side MOSFET gate driver of the Core VR. Connect the LGATE1 pin to the gate
of the Phase 1 low-side MOSFET(s).
Floating PWM output used for either Channel 3 of the Core VR or Channel 1 of the Northbridge VR
depending on the FCCM_NB resistor connected between FCCM_NB and GND.
5V bias power. A resistor [2Ω] and a decoupling capacitor should be used from the +5V supply. A high
quality, X7R dielectric MLCC capacitor is recommended.
Input voltage bias for the internal gate drivers. Connect +5V to the VDDP pin. Decouple with at least 1µF
of capacitance to GND. A high quality, X7R dielectric MLCC capacitor is recommended.
Output of the Phase 2 low-side MOSFET gate driver of the Core VR. Connect the LGATE2 pin to the gate
of the Phase 2 low-side MOSFET(s).
Current return path for the Phase 2 high-side MOSFET gate driver of the Core VR. Connect the PHASE2
pin to the node consisting of the high-side MOSFET source, the low-side MOSFET drain, and the output
inductor of Phase 2.
Output of the Phase 2 high-side MOSFET gate driver of the Core VR. Connect the UGATE2 pin to the gate
of the Phase 2 high-side MOSFET(s).
Connect an MLCC capacitor across the BOOT2 and PHASE2 pins. The boot capacitor is charged, through
an internal boot diode connected from the VDDP pin to the BOOT2 pin, each time the PHASE2 pin drops
below VDDP minus the voltage dropped across the internal boot diode.
Battery supply voltage, used for feed-forward.
Boot connection of the programmable internal driver used for either Channel 3 of the Core VR or
Channel 1 of the Northbridge VR based on the configuration state selected by the FCCM_NB resistor.
Connect an MLCC capacitor across the BOOT1X and the PHASEX pins. The boot capacitor is charged,
through an internal boot diode connected from the VDDP pin to the BOOTX pin, each time the PHASEX
pin drops below VDDP minus the voltage dropped across the internal boot diode.
8
FN8270.1
March 8, 2012