PM6670AS STMicroelectronics, PM6670AS Datasheet - Page 42

• 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

Application information
8.1.3
42/53
It must be taken into account that in some MLCC the capacitance decreases when the
operating voltage is near the rated voltage. In
applications are listed.
Table 14.
Output capacitor selection
Using tantalum or electrolytic capacitors, the selection is made referring to ESR and voltage
rating rather than by a specific capacitance value.
The output capacitor has to satisfy the output voltage ripple requirements. At a given
switching frequency, small inductor values are useful to reduce the size of the choke but
increase the inductor current ripple. Thus, to reduce the output voltage ripple a low ESR
capacitor is required.
To reduce jitter noise between different switching regulators in the system, it is preferable to
work with an output voltage ripple greater than 25 mV.
As far as it concerning the load transient requirements, the Equivalent Series Resistance
(ESR) of the output capacitor must satisfy the following relationship:
Equation 36
where V
In addition, the ESR must be high enough high to meet stability requirements. The output
capacitor zero must be lower than the switching frequency:
Equation 37
TAIYO YUDEN UMK325BJ106KM-T
TAIYO YUDEN
TAIYO YUDEN
TAIYO YUDEN
Manufacturer
TDK
RIPPLE
Evaluated MLCC for input filtering
is the maximum tolerable ripple voltage.
GMK325F106ZH-T
C3225X5R1E106M
GMK316F106ZL-T
GMK325BJ106KN
Series
Doc ID 14436 Rev 2
f
SW
Capacitance (μF) Rated voltage (V)
ESR
>
f
Z
≤
=
10
10
10
10
10
V
2
RIPPLE
⋅ π
Δ
Table 14
I
ESR
, L
MAX
1
,
MAX
⋅
C
some MLCC suitable for most of
out
35
35
25
50
35
Maximum Irms
@100 kHz (A)
2.2
2.2
2.5
PM6670AS
2