NCP3101BMNTXG ON Semiconductor, NCP3101BMNTXG Datasheet - Page 11

• Manufacturer Part Number: NCP3101BMNTXG
• Description: IC CONV VOLT SYNC BUCK 6A 40-QFN
• Manufacturer: ON Semiconductor
• Type: Step-Down (Buck)r

Specifications of NCP3101BMNTXG

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: Adj to 0.8V
• Current - Output: 6A
• Frequency - Switching: 275kHz
• Voltage - Input: 4.5 ~ 13.2 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Power - Output: 3W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Overcurrent Threshold Setting
50 mV to 450 mV by adding a resistor (RSET) between BG
and GND. During a short period of time following V
rising above the UVLO threshold, an internal 10 mA current
(IOCSET) is sourced from the BG pin, creating a voltage
drop across RSET. The voltage drop is compared against a
stepped internal voltage ramp. Once the internal stepped
voltage reaches the RSET voltage, the value is stored
internally until power is cycled. The overall time length for
the OC setting procedure is approximately 3 ms. When
connecting an RSET resistor between BG and GND, the
programmed threshold will be:
I
I
R
R
not connected or the RSET value is too high, the device
switches the OCP threshold to a fixed 96 mV value (5.3 A)
typical at 12 V. The internal safety clamp on BG is triggered
OCSET
OCTH
Switch Node Comparator
DS(on)
SET
The NCP3101C overcurrent threshold can be set from
The RSET values range from 5 kW to 45 kW. If RSET is
I
OCth
SCP Trip Voltage
Figure 24. Switching and Current Limit Timing
LS Gate Drive
HS Gate Drive
+
Switch Node
BG Comparator
SCP Comparator/
C Phase
I
OCSET
Latch Output
2V
2V
2V
R
= Sourced current
= Current trip threshold
= On resistance of the low side MOSFET
= Current set resistor
DS(on)
* R
SET
³ 7.2 A +
10 mA * 13 kW
18 mW
(eq. 1)
http://onsemi.com
CC
11
as soon as BG voltage reaches 700 mV, enabling the 96 mV
fixed threshold and ending the OC setting period. The
current trip threshold tolerance is $25 mV. The accuracy is
best at the highest set point (550 mV). The accuracy will
decrease as the set point decreases.
Drivers
switching MOSFETS with 1 A gate drivers. The gate drivers
also
non−overlap circuitry increases efficiency which minimizes
power dissipation by minimizing the low−side MOSFET
body diode conduction time.
circuitry used is shown in Figure 24.
required to realize the full benefit of the onboard drivers.
The capacitors between V
and CPHS must be placed as close as possible to the IC. A
ground plane should be placed on the closest layer for return
currents to GND in order to reduce loop area and inductance
in the gate drive circuit.
PWM
OUT
The NCP3101C drives the internal high and low side
A block diagram of the non−overlap and gate drive
Careful selection and layout of external components is
include
FAULT
UVLO
Figure 25. Block Diagram
adaptive
UVLO
FAULT
CC
-
-
+
+
non−overlap
and GND and between BST
2 V
2 V
circuitry.
PHASE
BST
TG
V
BG
GND
CC
The