PM6670AS STMicroelectronics, PM6670AS Datasheet - Page 43

• Manufacturer Part Number: PM6670AS
• Description: IC CTLR DDR2/3 MEM PS VFQFPN-24
• Manufacturer: STMicroelectronics

Specifications of PM6670AS

• Applications: Memory, DDR2/DDR3 Regulator
• Current - Supply: 800µA
• Voltage - Supply: 4.5 V ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-VFQFN, 24-VFQFPN
• For Use With: 497-8412 - BOARD EVAL PM6670AS DDR2/3497-8411 - BOARD EVAL PM6670S DDR2/3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PM6670AS
8.1.4
If ceramic capacitors are used, the output voltage ripple due to inductor current ripple is
negligible. Then the inductance could be smaller, reducing the size of the choke. In this case
it is important that output capacitor can adsorb the inductor energy without generating an
over-voltage condition when the system changes from a full load to a no load condition.
The minimum output capacitance can be chosen by the following equation:
Equation 38
where Vf is the output capacitor voltage after the load transient, while V
capacitor voltage before the load transient.
In
Table 15.
MOSFETs selection
In most of the applications, power management efficiency is a high level requirement. Power
dissipation on the power switches becomes an important factor in the selection of switches.
Losses of high-side and low-side MOSFETs depend on their working condition.
Considering the high-side MOSFET, the power dissipation is calculated as:
Equation 39
Maximum conduction losses are approximately given by:
Equation 40
Table 15
Manufacturer
HITACHI
SANYO
are listed some tested polymer capacitors are listed.
Evaluated output capacitors
TNCB OE227MTRYF
4TPE220MF
4TPE150MI
4TPC220M
Series
P
conduction
P
Doc ID 14436 Rev 2
DHighSide
C
OUT
=
R
,
min
=
Capacitance
DSon
P
conduction
=
(μF)
220
220
220
220
L
⋅
Vf
V
⋅
V
I
IN
LOAD
OUT
2
.
min
−
+
Vi
,
MAX
P
⋅
I
2
switching
LOAD
Rated voltage
2
,
MAX
2.5 V
4 V
4 V
4 V
(V)
2
Application information
I
ESR max @100 kHz
is the output
15 to 25
(mΩ)
25
18
40
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