STEVAL-ISA051V1 STMicroelectronics, STEVAL-ISA051V1 Datasheet - Page 26

• Manufacturer Part Number: STEVAL-ISA051V1
• Description: BOARD EVAL PM6670S DDR2/3
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of STEVAL-ISA051V1

• Design Resources: STEVAL-ISA051V1 Gerber Files STEVAL-ISA051V1 Schematic STEVAL-ISA051V1 Bill of Material
• Main Purpose: Special Purpose DC/DC, DDR Memory Supply
• Outputs And Type: 4, Non-Isolated
• Voltage - Output: 1.5V, 1.8V
• Voltage - Input: 4.5 ~ 28V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: PM6670
• Input Voltage: 4.5 V to 28 V
• Output Voltage: 1.8 V, 1.5 V
• Product: Power Management Modules
• Silicon Manufacturer: ST Micro
• Silicon Core Number: PM6670S
• Kit Application Type: Power Management
• Application Sub Type: DDR2/3 Memory Power Supply Controller
• Kit Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: PM6670S
• Other names: 497-8411

Device description
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Figure 32. “Virtual-ESR” network
The ripple on the COMP pin is the sum of the output voltage ripple and the triangular ripple
generated by the Virtual-ESR network. In fact the Virtual-ESR Network behaves like a
another equivalent series resistor R
A good trade-off is to design the network in order to achieve an RVESR given by:
Equation 11
where ΔI
greater than approximately 20 mV.
The new closed-loop gain depends on C
that:
Equation 12
where:
Equation 13
and:
T NODE
VOLTAGE
L
is the inductor current ripple and V
ΔV
1
OUTPUT
VOLTAGE
R
R
ΔV
T
COMP PIN
VOLTAGE
t
Doc ID 14432 Rev 4
V
REF
C
R
R
C
R
R
1
R
1
INT
INT
VESR
VESR
C
f
t
Z
INT
C
=
C
INT
.
INT
INT
2
=
>
⋅ π
V
. In order to ensure stability it must be verified
2
RIPPLE
g
⋅ π
C
RIPPLE
COMP
Δ
COMP
ESR
ESR
C
C
t
m
out
VSNS
I
f
L
ΔV
OUT
OUT
1
Z
C
C
⋅
2
FILT
⋅
FILT
R
Vout
−
Vr
TOT
is the total ripple at the T node, chosen
ESR
I=g
m
Vr
Vr
(V
1
-Vr)
R
R
Fb2
Fb2
g
g
V
V
m
m
1
1
+
V
V
REF
REF
R
R
Fb1
Fb1
+
-
Comparator
Comparator
PWM
PWM
PM6670S