ISL6329 Datasheet, PDF (6/38 Pages) Intersil Corporation – Dual PWM Controller Powering AMD SVI Split-Plane Processors

ISL6329
Functional Pin Descriptions (Continued)
PIN NAME
SDA
VCC
RSVD
OFS
OCP
TCOMP1, TCOMP2
RGND
VSEN
FB_PSI
FB
COMP
FS
APA
ISENn+, ISENn-,
ISEN_NB+, ISEN_NB-
PHASE1, PHASE2
GND
EN
UGATE1, UGATE2
PIN NUMBER
9
DESCRIPTION
Connect this pin to the bidirectional data line of the I²C bus, which is a logic level input/output signal.
All I²C data is sent over this line, including the address of the device the bus is trying to communicate
with and what functions the device should perform.
10
VCC is the bias supply for the ICs small-signal circuitry. Connect this pin to a +5V supply and decouple
using a quality 0.1µF ceramic capacitor.
11
RESERVED. Connect this pin directly to the VCC pin.
12
The OFS pin provides a means to program a DC current for generating an offset voltage across the resistor
between FB and VSEN. The offset current is generated via an external resistor and precision internal
voltage references. The polarity of the offset is selected by connecting the resistor to GND or VCC. For no
offset, the OFS pin should be left unconnected.
13
A capacitor from this pin to ground determines the time that the regulator is allowed to service a load
current spike that exceeds the internal OCP trip point.
14, 15
These two pins are used to compensate the inductor current sensing for fluctuations due to
temperature.
16
Inverting input to the Core and Northbridge regulator precision differential remote-sense amplifiers. This
pin should be connected to the remote ground sense pin of the processor core, VSS_SENSE.
17
Non-inverting input to the Core regulator precision differential remote-sense amplifier. This pin should be
connected to the remote Core sense pin of the processor, VDD_SENSE.
18
In PSI mode this pin is internally shorted to the FB pin to augment the feedback compensation network
for the lower phase count.
19
Inverting input to the internal error amplifier for the Core regulator.
20
Output of the internal error amplifier for the Core regulator.
21
This is a dual function pin. A resistor, placed from FS to either Ground or VCC sets the switching
frequency of both controllers. Refer to Equation 1 for proper resistor calculation.
R_T
=
[ 10.61
10
–
1.035
log
(
fs)
]
(EQ. 1)
If the resistor is tied to ground, the number of active phases in PSI mode is 1. If the resistor is tied to
VCC, the number of active phases in PSI mode is 2.
22
Allows for programming of the Auto Phase Alignment threshold. A resistor in parallel with a capacitor
to ground is used to set this threshold.
23, 24, 25, 26,
27, 28, 53, 54,
55, 56, 57, 58,
59, 60
40, 29
These pins are used for differentially sensing the corresponding channel output currents. The sensed
currents are used for channel balancing, protection, and core load line regulation.
Connect ISEN- to the node between the RC sense elements surrounding the inductor of the respective
channel. Tie the ISEN+ pin to the other end of the sense capacitor through a resistor, R_ISEN. The voltage
across the sense capacitor is proportional to the inductor current. The sense current, therefore, is
proportional to the inductor current and scaled by the DCR of the inductor and R_ISEN.
Connect these pins to the sources of the corresponding upper MOSFETs. These pins are the return path
for the upper MOSFET drives.
30, 32, 61
Bias and reference ground for the IC. The GND connection for the ISL6329 is made with three pins and
through the thermal pad on the bottom of the package.
31
This pin is a threshold-sensitive (approximately 0.85V) system enable input for the controller. Held low, this
pin disables both CORE and NB controller operation. Pulled high, the pin enables both controllers for
operation.
A second function of this pin is to provide driver bias monitor for external drivers. A resistor divider with the
center tap connected to this pin from the drive bias supply prevents enabling the controller before
insufficient bias is provided to external driver. The resistors should be selected such that when the POR-
trip point of the external driver is reached, the voltage at this pin meets the above mentioned threshold
level.
39, 33
Connect this pin to the corresponding upper MOSFET gate. This pin provides the PWM-controlled gate
drive for the upper MOSFET and is monitored for shoot-through prevention purposes.
6
FN7800.0
April 19, 2011