hip6303cbz-t Intersil Corporation, hip6303cbz-t Datasheet - Page 14

• Manufacturer Part Number: hip6303cbz-t
• Description: Microprocessor Core Voltage Regulator Multiphase Buck Pwm Controller
• Manufacturer: Intersil Corporation

The critical small components include the bypass capacitors
for VCC and PVCC on the gate driver ICs. Locate the
bypass capacitor, C
the device. It is especially important to locate the resistors
associated with the input to the amplifiers close to their
respective pins, since they represent the input to feedback
amplifiers. Resistor R
should also be located next to the associated pin. It is
especially important to place the R
respective terminals of the HIP6303.
A multi-layer printed circuit board is recommended. Figure 11
shows the connections of the critical components for one
output channel of the converter. Note that capacitors C
C
Dedicate one solid layer, usually the middle layer of the PC
board, for a ground plane and make all critical component
ground connections with vias to this layer. Dedicate another
solid layer as a power plane and break this plane into smaller
islands of common voltage levels. Keep the metal runs from
the PHASE terminal to inductor L
should support the input power and output power nodes. Use
copper filled polygons on the top and bottom circuit layers for
the phase nodes. Use the remaining printed circuit layers for
small signal wiring. The wiring traces from the driver IC to the
MOSFET gate and source should be sized to carry at least
one ampere of current.
Component Selection Guidelines
Output Capacitor Selection
The output capacitor is selected to meet both the dynamic
load requirements and the voltage ripple requirements. The
load transient for the microprocessor CORE is characterized
OUT
LOCATE NEXT
could each represent numerous physical capacitors.
TO FB PIN
+5V
BP
IN
C
R
R
T
BP
C
FB
, for the HIP6303 controller close to
IN
, that sets the oscillator frequency
T
14
FIGURE 11. PRINTED CIRCUIT BOARD POWER PLANES AND ISLANDS
LOCATE NEXT TO IC PIN(S)
COMP
FB
V
VSEN
O1
CC
SEN
HIP6303
short. The power plane
FS/DIS
resistor(s) at the
PWM
ISEN
R
LOCATE NEXT TO IC PIN
SEN
R
T
C
BP
IN
and
HIP6303
+12V
VCC
HIP6601
PVCC
by high slew rate (di/dt) current demands. In general,
multiple high quality capacitors of different size and dielectric
are paralleled to meet the design constraints.
Modern microprocessors produce severe transient load rates.
High frequency capacitors supply the initially transient current
and slow the load rate-of-change seen by the bulk capacitors.
The bulk filter capacitor values are generally determined by
the ESR (effective series resistance) and voltage rating
requirements rather than actual capacitance requirements.
High frequency decoupling capacitors should be placed as
close to the power pins of the load as physically possible. Be
careful not to add inductance in the circuit board wiring that
could cancel the usefulness of these low inductance
components. Consult with the manufacturer of the load on
specific decoupling requirements.
Use only specialized low-ESR capacitors intended for
switching-regulator applications for the bulk capacitors. The
bulk capacitor’s ESR determines the output ripple voltage
and the initial voltage drop following a high slew-rate
transient’s edge. In most cases, multiple capacitors of small
case size perform better than a single large case capacitor.
Bulk capacitor choices include aluminum electrolytic, OS-
Con, Tantalum and even ceramic dielectrics. An aluminum
electrolytic capacitor’s ESR value is related to the case size
with lower ESR available in larger case sizes. However, the
equivalent series inductance (ESL) of these capacitors
increases with case size and can reduce the usefulness of
the capacitor to high slew-rate transient loading.
Unfortunately, ESL is not a specified parameter. Consult the
capacitor manufacturer and measure the capacitor’s
impedance with frequency to select a suitable component.
PHASE
C
KEY
BOOT
ISLAND ON POWER PLANE LAYER
ISLAND ON CIRCUIT PLANE LAYER
VIA CONNECTION TO GROUND PLANE
USE INDIVIDUAL METAL RUNS
FOR EACH CHANNEL TO HELP
ISOLATE OUTPUT STAGES
C
L
IN
O1
C
OUT
LOCATE NEAR TRANSISTOR
V
CORE