L6738ATR STMicroelectronics, L6738ATR Datasheet - Page 21

• Manufacturer Part Number: L6738ATR
• Description: IC PWM CTLR 1PH STPDN 16-VFQFPN
• Manufacturer: STMicroelectronics

Specifications of L6738ATR

• Frequency - Max: 220kHz
• Pwm Type: Voltage Mode
• Number Of Outputs: 1
• Duty Cycle: 100%
• Voltage - Supply: 5 V ~ 12 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 32-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-11012-2

L6738A
Two main terms contribute in the device power dissipation: bias power and drivers' power.
●
●
Device Power (P
supply pins and it is simply quantifiable as follows:
Drivers' power is the power needed by the driver to continuously switch ON and OFF
the external MOSFETs; it is a function of the switching frequency and total gate charge
of the selected MOSFETs. It can be quantified considering that the total power P
dissipated to switch the MOSFETs, is dissipated by three main factors: external gate
resistance (when present), intrinsic MOSFET resistance and intrinsic driver resistance.
This last term is the important one to be determined to calculate the device power
dissipation.
The total power dissipated to switch the MOSFETs for each phase featuring embedded
driver results:
where Q
charge of the LS MOSFETs.
GHS
is the total gate charge of the HS MOSFETs and Q
DC
P
SW
) depends on the static consumption of the device through the
=
P
F
DC
SW
Doc ID 18134 Rev 1
=
⋅
V
(
Q
CC
GHS
⋅
I
⋅
CC
VCCDR
+
V
VCCDR
+
Q
⋅
GLS
I
VCCDR
High Current embedded drivers
⋅
VCCDR
GLS
)
is the total gate
SW
21/32
,