STEVAL-ISA051V1 STMicroelectronics, STEVAL-ISA051V1 Datasheet - Page 22
![BOARD EVAL PM6670S DDR2/3](/photos/9/13/91334/steval-isa051v1_sml.jpg)
STEVAL-ISA051V1
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
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
STEVAL-ISA051V1
Manufacturer:
STMicroelectronics
Quantity:
1
Device description
22/54
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 PM6670S
switching frequency can be set by an external divider connected to the VOSC pin.
Figure 29. Switching frequency selection and VOSC pin
The suggested voltage range for VOSC pin is 0.3 V to 2 V, for better switching frequency
programmability.
f
SW
Doc ID 14432 Rev 4
=
f
SW
R2
R1
T
D
ON
VIN
=
K
α
=
α
OSC
OSC
α
K
OSC
OUT
D
OSC
=
V
=
VOSC
V
OUT
=
=
V
--------------
IN
R
V
V
V
OUT
PM6670S
1
V
-------------- -
--------------
V
OSC
V
SNS
PM6670
IN
R
V
+
OSC
OUT
SNS
2
IN
R
2
=
⋅
α
α
K
OSC
OUT
OSC
1
⋅
K
OSC
1
Figure 29
PM6670S
), the