L6728A STMicroelectronics, L6728A Datasheet - Page 23

• Manufacturer Part Number: L6728A
• Description: Voltage Mode PWM Controllers Hi-Freq. singl-phase PWM controller w/Po
• Manufacturer: STMicroelectronics

Specifications of L6728A

• Number Of Outputs: Dual Output
• Topology: Buck
• Output Voltage: 0.8 V
• Output Current: 1500 mA
• Switching Frequency: 660 KHz
• Duty Cycle (max): 67 %
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Package / Case: VFDFPN-10 EP
• Synchronous Pin: No
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

L6728A
11.1
11.1.1
11.1.2
Note:
11.1.3
11.1.4
Demonstration board description
Power input (V
This is the input voltage for the power conversion. The high-side drain is connected to this
input. This voltage can range from 1.5 V to 12 V bus.
If the voltage is between 5 V and 12 V it can supply also the device (through the V
and in this case the R16 (0 Ω) resistor must be present.
Output (V
Different output voltage rails have been tested. For each rail a few component need to be
changed: these components are used to program the desiderated output voltage and to
compensate the system. The over-current-protection limit is set to ~27 A but it can be
changed by replacing the resistors R18.
Table 7.
All the previous resistors are SMD 0603 package, 1/16W, 1% tolerance.
Signal input (V
Using the input voltage V
However the controller can be supplied separately from the power stage through the V
input and, in this case, the R16 (0 Ω) resistor must be unsoldered.
Test points
Several test points are provided to have easy access at all important signal characterizing
the device:
R8, R13
R6, R9
Ref.
–
–
–
–
–
–
–
Q9
R7
COMP: the output of the error amplifier;
FB: the inverting input of the error amplifier;
PGOOD: signaling the regular functioning (active high);
VGDHS: the bootstrap diode anode;
PHASE: Phase node;
LGATE: Low-side gate pin of the device;
HGATE: High-side gate pin of the device.
OUT
Rail dependent components
8 V rail
3.6 kΩ
3.6 kΩ
)
390 Ω
IN
CC
)
mounted
)
IN
to supply the controller no power is required at this input.
5 V rail
3.6 kΩ
3.6 kΩ
680 Ω
3.3 V rail
3.6 kΩ
4.7 kΩ
1.5 kΩ
2.5 V rail
3.6 kΩ
4.7 kΩ
2.2 kΩ
not mounted
20 A demonstration board
1.25 V rail
11 kΩ
22 kΩ
39 kΩ
0.8 V rail
CC
11 kΩ
22 kΩ
open
pin)
CC
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