PM6670ASTR STMicroelectronics, PM6670ASTR Datasheet - Page 47

• Manufacturer Part Number: PM6670ASTR
• Description: IC CTLR DDR2/3 MEM PS 24VFQFPN
• Manufacturer: STMicroelectronics

Specifications of PM6670ASTR

• Applications: Memory, DDR2/DDR3 Regulator
• Current - Supply: 800µA
• Voltage - Supply: 4.5 V ~ 36 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
• Other names: 497-6305-2; PM6670ATR

PM6670AS
8.1.7
All ceramic capacitors application
Design of external feedback network depends on the output voltage ripple across the output
capacitors' ESR. If the ripple is great enough (at least 20 mV), the compensation network
simply consists of a C
Figure 40. Integrative compensation
The stability of the system depends firstly on the output capacitor zero frequency. It must be
verified that:
Equation 48
where k is a free design parameter greater than unity (k > 3). It determines the minimum
integrator capacitor value C
Equation 49
COMP
C
FILT
R
INT
INT
VREF
capacitor.
INT
Doc ID 14436 Rev 2
:
C
Integrator
C
f
INT
SW
Ton One-shot
INT
generator
>
>
Comparator
+
-
2
k
⋅ π
⋅
PWM
f
Zout
⎛
⎜
⎝
g
f
m
SW
k
g
=
+
m
-
−
2
⋅ π
f
Zout
R
k
out
⎞
⎟
⎠
Vr=0.9
⋅
C
Vref
Vo
out
Application information
VSNS
VDDQ
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