ISL8102 Intersil Corporation, ISL8102 Datasheet - Page 7

• Manufacturer Part Number: ISL8102
• Description: Two-Phase Buck PWM Controller
• Manufacturer: Intersil Corporation

Timing Diagram
Simplified Power System Diagram
Functional Pin Description
VCC (Pin 3)
Bias supply for the IC’s small-signal circuitry. Connect this
pin to a +5V supply and locally decouple using a quality
1.0µF ceramic capacitor.
PVCC (Pin 15)
Power supply pin for the MOSFET drive. This pin can be
connected to any voltage from +5V to +12V, depending on
the desired MOSFET gate drive level.
GND (Pin 33)
Bias and reference ground for the IC.
ENLL (Pin 20)
This pin is a threshold sensitive (approximately 0.66V) enable
input for the controller. Held low, this pin disables controller
UGATE
LGATE
+12V
+5V
REF0,REF1
IN
IN
PGOOD
ENLL
OVP
t
PDHUGATE
7
t
FLGATE
2
DAC
ISL8102
t
RUGATE
ISL8102
CHANNEL1
CHANNEL2
operation. Pulled high, the pin enables the controller for
operation.
FS (Pin 29)
A resistor, placed from FS to ground, will set the switching
frequency. Refer to Equation 33 and Figure 24 for proper
resistor calculation.
2PH (Pin 31)
This pin is used to choose between single or two phase
operation. Tying this pin to VCC allows for 2-phase operation.
Tying the 2PH pin to GND causes the controller to operate in
a single phase mode.
REF0 and REF1 (Pins 30, 21)
These pins make up the 2-bit input that selects the fixed DAC
reference voltage. These pins respond to TTL logic
thresholds. The ISL8102 decodes these inputs to establish
Q3
Q4
Q1
Q2
t
PDHLGATE
t
FUGATE
t
RLGATE
V
OUT
October 19, 2005
FN9247.0