CS51413EDR8G ON Semiconductor, CS51413EDR8G Datasheet - Page 9

• Manufacturer Part Number: CS51413EDR8G
• Description: IC REG BUCK LV 1.5A SYNC 8SOIC
• Manufacturer: ON Semiconductor
• Type: Step-Down (Buck)r

Specifications of CS51413EDR8G

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Current - Output: 1.5A
• Frequency - Switching: 520kHz
• Voltage - Input: 4.5 ~ 40 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Mounting Style: SMD/SMT
• Primary Input Voltage: 40V
• No. Of Outputs: 1
• Output Current: 1.5A
• No. Of Pins: 8
• Operating Temperature Range: -40°C To +85°C
• Current Rating: 1.5A
• Filter Terminals: SMD
• Input Voltage Primary Max: 40V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: CS51413EDR8GOS

Semiconductor application note AND8276/D on V2 and the
CS5141x demonstration board number.
Error Amplifier
whose noninverting input is connected to an Internal
Reference Voltage generated from the on−chip regulator. The
inverting input connects to the V
error amplifier is made available at the V
frequency compensation requires only a 0.1 mF capacitor
connected between the V
Figure 1. This capacitor and error amplifier’s output
resistance (approximately 8.0 MW) create a low frequency
pole to limit the bandwidth. Since V2 control does not require
a
compensation is greatly simplified.
allows the regulator to recover quickly from overcurrent or
short circuit conditions.
Oscillator and Sync Feature (CS51411 and CS51413 only)
no external components for frequency control. The high
switching frequency allows smaller external components to be
used, resulting in a board area and cost savings. The tight
frequency tolerance simplifies magnetic components election.
The switching frequency is reduced to 25% of the nominal
value when the V
Threshold. In short circuit or overload conditions, this reduces
the power dissipation of the IC and external components.
higher frequency. The rising edge of the sync pulse turns on the
power switch to start a new switching cycle, as shown in
Figure 11. There is approximately 0.5 ms delay between the
rising edge of the sync pulse and rising edge of the V
voltage. The sync threshold is TTL logic compatible, and duty
cycle of the sync pulses can vary from 10% to 90%. The
frequency foldback feature is disabled during the sync mode.
100
Some representative efficiency data is shown in Figure 10.
More detailed information is available in the ON
The CS5141X has a transconductance error amplifier,
The V
The on−chip oscillator is trimmed at the factory and requires
An external clock signal can sync CS51411/CS51414 to a
80
60
40
20
high
0
0
Figure 10. Efficiency versus Output Current
C
pin is clamped below Output High Voltage. This
bandwidth
FB
I
OUT
pin voltage is below Frequency Foldback
, OUTPUT CURRENT (mA)
500
error
C
pin and ground, as shown in
Vin = 5.5 V, Vout= 3.3 V
Vin = 7.5 V, Vout = 5.0 V
Vin = 15V, Vout = 12 V
amplifier,
FB
pin. The output of the
1000
C
the
pin. A typical
frequency
http://onsemi.com
SW
1500
pin
9
Power Switch and Current Limit
connected to the V
When the switch turns on, the V
V
the V
when the power switch turns off, and the inductor current is
commutated to the catch diode. Due to the presence of high
pulsed current, the traces connecting the V
and diode should be kept as short as possible to minimize the
noise and radiation. For the same reason, the input capacitor
should be placed close to the V
diode.
on the switching current, as shown in Figure 12.
current limiting to protect the power switch and external
components. When the peak of the switching current reaches
the Current Limit, the power switch turns off after the
Current Limit Delay. The switch will not turn on until the
next switching cycle. The current limit threshold is
Figure 11. A CS51411 Buck Regulator is Synced by an
Figure 12. The Saturation Voltage of the Power Switch
IN
The collector of the built−in NPN power switch is
The saturation voltage of the power switch is dependent
Members of the CS5141X family contain pulse−by−pulse
0.7
0.6
0.5
0.4
0.3
0.2
0.1
minus switch Saturation Voltage. In the buck regulator,
0
SW
0
Increases with the Conducting Current
voltage swings to one diode drop below ground
External 350 kHz Pulse Signal
IN
SWITCHING CURRENT (A)
pin, and the emitter to the V
0.5
IN
SW
pin and the anode of the
voltage is equal to the
1.0
SW
pin, inductor
SW
pin.
1.5