iru3048 International Rectifier Corp., iru3048 Datasheet - Page 3

• Manufacturer Part Number: iru3048
• Description: Dual Synchronous Pwm Controller Circuitry And Ldo Controller
• Manufacturer: International Rectifier Corp.

PARAMETER
Error Amp
Fb Voltage Input Bias Current
Fb Voltage Input Bias Current
Transconductance 1
Transconductance 2
Oscillator
Frequency
Ramp Amplitude
Output Drivers
Rise Time
Fall Time
Dead Band Time
Max Duty Cycle
Min Duty Cycle
LDO Controller
Drive Current
Fb Voltage
Input Bias Current
PIN DESCRIPTIONS
PIN#
Rev. 1.7
09/12/02
16
12
10
13
14
15
11
1
2
3
4
5
6
7
8
9
PIN SYMBOL
Comp1
Comp2
HDrv2
HDrv1
VcH2
VcH1
LDrv2
LDrv1
PGnd
V
Gnd
Fb2
Fb1
Vcc
Fb3
SS
OUT3
Ground pin.
Inverting inputs to the error amplifiers. These pins work as feedback inputs for each
channel, and are connected directly to the output of the switching regulator via a resistor
divider to set the output voltages.
Compensation pins for the error amplifiers.
Supply voltage for the high side output drivers. These are connected to voltages that
must be at least 4V higher than their bus voltages (assuming 5V threshold MOSFET). A
minimum of 1mF high frequency capacitor must be connected from these pins to PGnd
pin to provide peak drive current capability.
Output driver for the high side power MOSFET. Connect a diode, such as BAT54 or
1N4148, from these pins to ground for the application when the inductor current goes
negative (Source/Sink), soft-start at no load and for the fast load transient from full load to
no load.
Output driver for the synchronous power MOSFET.
This pin serves as the separate ground for MOSFET’s driver and should be connected to
the system’s ground plane.
Supply voltage for the internal blocks of the IC.
Driver signal for the LDO’s external transistor.
LDO’s feedback pin, connected to a resistor divider to set the output voltage of LDO.
Soft-Start pin. The converter can be shutdown by pulling this pin below 0.5V.
PIN DESCRIPTION
V
I
LDO(BIAS)
V
SYM
Freq
FB
T
g
g
T
T
I
I
I
RAMP
LDO
FB1
FB2
Tr
Tf
OFF
LDO
m1
m2
DB
ON
SS=3V
SS=0V
C
C
Fb=1V, Freq=200KHz
Fb=1.5V
L
L
=1500pF
=1500pF
www.irf.com
TEST CONDITION
1.225
MIN
180
50
85
30
0
1.25
1.25
TYP
-0.1
400
600
200
150
-64
0.5
35
50
90
45
0
IRU3048
1.275
MAX
220
100
100
250
2
UNITS
mmho
mmho
KHz
mA
mA
mA
V
mA
ns
ns
ns
%
%
V
PP
3