IP1001 International Rectifier, IP1001 Datasheet - Page 11

• Manufacturer Part Number: IP1001
• Description: IC PWR BLOCK SGL PHS 20A 256-BGA
• Manufacturer: International Rectifier
• Series: iPOWIR™r
• Type: Step-Down (Buck)r

Specifications of IP1001

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.93 ~ 2 V
• Current - Output: 20A
• Frequency - Switching: 200kHz, 300kHz
• Voltage - Input: 3.3 ~ 12 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 256-BGA (218 bumps)
• Power - Output: 3.1W
• For Use With: IRDCIP1001-A - CONV SGL PHA SYNC BUCK 3.3-4.5V
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *IP1001

DESIGN PROCEDURE
Inductor Selection
The inductor is selected according to the following
expression.
where, D = V
The inductor value should be selected from 0.8 H
to 2.0 H range.
Output Capacitor Selection
Use tantalum or POSCAP type capacitors for iP1001.
Selection of the output capacitors depends on
several factors.
•
•
To support the load transients and to stay within a
specified voltage dip V due to the transients, ESR
selection should satisfy the following equation:
where,
If output voltage ripple is required to be maintained
at specified levels then, the following expression
should be used to select the output capacitors.
where, V
The value of the output capacitor ESR zero frequency
also determines stability. The value of the ESR zero
frequency is calculated by the expression:
www.irf.com
Low effective ESR for ripple and load transient
requirements.
Stability.
L = V
V
fsw is the switching frequency in kHz,
R
R
R
p-p
I is the transient load step
OUT
I
ESR
ESR
ESR
L
is the peak to peak output voltage ripple.
is the output inductor ripple current.
is the output voltage in Volts,
= 1 / (2
OUT
OUT
V
p-p
x
V/ I
/ V
(1-D) / (fsw
/ I
IN
L
x
f
ESR
x
C
x
OUT
I
L
)
)
of ESR which provides 9.7kHz zero frequency.
The ESR zero frequency must be set below 12kHz.
This value is calculated assuming the capacitor
datasheet maximum ESR value.
Example:
For stable operation:
•
inductor and capacitor between 2kHz and 4kHz.
The resonant frequency is calculated using the
following expression:
•
to 2.0 H and the output capacitance between
1880 F (4x 470 F) and 5600 F (12x470 F)
•
greater than 0.5% of the output voltage. Select the
capacitor by ESR and by voltage rating rather than
capacitance.
External Input Capacitor Selection
The switching currents impose RMS current
requirements on the input capacitors. The following
expression allows the selection of the input
capacitors, based on the input RMS current:
where, D = V
A 470 F POSCAP capacitor has a maximum 35m
Select the output inductor value between 0.8 H
Set the minimum output ripple voltage to be
Set the resonant frequency f
To determine the amount of capacitance
to meet a 30mVp-p output ripple, with 4A
inductor current ripple requirement.
The calculated ESR will be = 30mV/4A =
7.5m . This will require 5 x 470uF POSCAP
capacitors. The total ESR will result in a
9.7kHz zero frequency.
f
I
o
RMS
= 1/ (2
= I
OUT
LOAD
/V
IN
x
x
( LC))
( D
x
(1-D))
o
iP1001
of the output
11