PM6680A STMicroelectronics, PM6680A Datasheet - Page 40
PM6680A
Manufacturer Part Number
PM6680A
Description
IC CTLR DUAL SYNC STDN 5X5VFQFPN
Manufacturer
STMicroelectronics
Datasheet
1.PM6680ATR.pdf
(48 pages)
Specifications of PM6680A
Applications
Controller, Embedded Computer System
Voltage - Input
6 ~ 36 V
Number Of Outputs
2
Voltage - Output
0.9 ~ 5 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
32-VFQFN, 32-VFQFPN
For Use With
497-6379 - BOARD EVALUATION FOR PM6680A497-6378 - BOARD EVALUATION FOR PM6680497-6425 - BOARD EVAL BASED ON PM6680A
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
PM6680ATR
Manufacturer:
STMicroelectronics
Quantity:
10 000
Design guidelines
9.8
40/48
Figure 40. Bootstrap circuit
The bootstrap circuit capacitor value C
side MOSFET during turn on phase. A typical value is 100 nF.
The bootstrap diode D must charge the capacitor during the off time phases. The maximum
rated voltage must be higher than V
A resistor R
node rises up, working like a gate resistor for the turn on phase of the high side MOSFET.
Design example
The following design example considers an input voltage from 16 V to 32 V(the typical value
is 24 V). The two switching outputs are OUT1 = 3.3 V and OUT2 = 1.8 V and must deliver a
maximum current of 2.5 A. The selected switching frequencies are about 290 kHz for OUT1
section and about 440 kHz for OUT2 section (see
1.
OUT1: ILOAD = 2.5 A, 45 % ripple current.
Equation 36
We choose standard value L= 8.2 µH.
∆I
I
I
OUT2:ILOAD=2.5 A, 35 % ripple current.
LRMS
peak
L(max)
Inductor selection
= 2.5 A + 0.58 A = 3.83 A
= 2.523 A
= 1.16 A @VIN = 24 V.
BOOT
on the BOOT pin could be added in order to reduce noise when the phase
L
L
INmax
BOOT
C
C
.
R
R
B
B
O
B
B
O
must provide the total gate charge to the high
O
O
O
O
O
O
T
T
D
D
T
T
B
P
B
P
Table 6
O
H
H
O
L
L
A
A
O
O
D
D
S
S
T
T
O
O
E
E
5
5
).
PM6680A