STEVAL-ISA051V2 STMicroelectronics, STEVAL-ISA051V2 Datasheet - Page 22
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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
Device description
7.1.1
22/53
Figure 27. Switching frequency selection and VOSC pin
The suggested voltage range for VOSC pin is 0.3V to 2V, for better switching frequency
programmability.
Constant-on-time architecture
Figure 28
The switching regulator of the PM6670AS owns a one-shot generator that ignites the high-
side MOSFET when the following conditions are simultaneously satisfied: the PWM
comparator is high (i.e. output voltage is lower than Vr = 0.9 V), the synchronous rectifier
current is below the current limit threshold and the minimum off-time has expired.
A minimum off-time constraint (300 ns typ.) is introduced to assure the boot capacitor
charge and allow inductor valley current sensing on low-side MOSFET. A minimum on-time
is also introduced to assure the start-up switching sequence.
Once the on-time has timed out, the high side switch is turned off, while the synchronous
rectifier is ignited according to the anti-cross conduction management circuitry.
When the output voltage reaches the valley limit (determined by internal reference
Vr = 0.9 V), the low-side MOSFET is turned off according to the anti-cross conduction logic
once again, and a new cycle begins.
shows the simplified block diagram of the constant-on-time controller.
Doc ID 14436 Rev 2
R2
R1
VIN
VOSC
PM6670AS
PM6670
PM6670AS