STEVAL-ISA051V2 STMicroelectronics, STEVAL-ISA051V2 Datasheet - Page 21
![BOARD EVAL PM6670AS DDR2/3](/photos/9/13/91339/steval-isa051v2_sml.jpg)
STEVAL-ISA051V2
Manufacturer Part Number
STEVAL-ISA051V2
Description
BOARD EVAL PM6670AS DDR2/3
Manufacturer
STMicroelectronics
Type
DC/DC Switching Converters, Regulators & Controllersr
Specifications of STEVAL-ISA051V2
Design Resources
STEVAL-ISA051V2 Gerber Files STEVAL-ISA051V2 Schematic STEVAL-ISA051V2 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 ~ 36V
Regulator Topology
Buck
Board Type
Fully Populated
Utilized Ic / Part
PM6670A
Input Voltage
4.5 V to 36 V
Output Voltage
1.8 V, 1.5 V
Product
Power Management Modules
Silicon Manufacturer
ST Micro
Silicon Core Number
PM6670AS
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
PM6670AS
Other names
497-8412
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
STEVAL-ISA051V2
Manufacturer:
STMicroelectronics
Quantity:
1
PM6670AS
The duty-cycle of the buck converter is, in steady-state conditions, given by
Equation 2
The switching frequency is thus calculated as
Equation 3
where
Equation 4a
Equation 4b
Referring to the typical application schematic (figures on cover page and
final expression is then:
Equation 5
Even if the switching frequency is theoretically independent from battery and output
voltages, parasitic parameters involved in power path (like MOSFETs' on-resistance and
inductor's DCR) introduce voltage drops responsible for slight dependence on load current.
In addition, the internal delay is due to a small dependence on input voltage. The
PM6670AS switching frequency can be set by an external divider connected to the VOSC
pin.
f
SW
Doc ID 14436 Rev 2
=
f
SW
T
D
ON
=
K
α
=
α
OSC
OSC
α
K
OSC
OUT
D
OSC
=
V
=
V
OUT
=
=
V
--------------
IN
R
V
V
V
OUT
1
V
-------------- -
--------------
V
OSC
V
SNS
IN
R
V
+
OSC
OUT
SNS
2
IN
R
2
=
⋅
α
α
K
OSC
OUT
OSC
1
⋅
K
OSC
1
Device description
Figure 27
), the
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