S-8521F25MC-BPKT2G Seiko Instruments, S-8521F25MC-BPKT2G Datasheet - Page 14

• Manufacturer Part Number: S-8521F25MC-BPKT2G
• Description: IC REG PWM/PFM 300KHZ SOT23-5
• Manufacturer: Seiko Instruments
• Type: Step-Down (Buck)r

Specifications of S-8521F25MC-BPKT2G

• Internal Switch(s): No
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 2.5V
• Current - Output: 120mA
• Frequency - Switching: 300kHz
• Voltage - Input: 2.5 ~ 16 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5, SC-74A, SOT-25
• Power - Output: 250mW
• Output Voltage: 2.5 V
• Input Voltage: 2.5 V to 16 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

14
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
2. Soft start function
3. ON/OFF
The ON/OFF
Setting the ON/OFF
significantly. The EXT pin’s voltage is set to the V
Do not use the ON/OFF
or pulled down internally. Do not apply a voltage of between 0.3 V and 1.8 V to the ON/OFF
such a voltage increases the current consumption. When not using the ON/OFF
The S-8520/8521 Series has a built-in soft start-circuit. This circuit enables the output voltage (V
gradually over the specified soft start time (t), when power-on or when the ON/OFF
prevents the output voltage from overshooting.
However, the soft-start function of this IC is not able to perfectly prevent a rush current from flowing to the load
(Refer to Figure 8). Since this rush current depends on the input voltage and load conditions, Perform sufficient
evaluation with actual device for design.
_______
______
pin (Shutdown pin)
pin stops or starts step-up operation.
______
Rush current
Figure 8 Waveforms of output voltage and rush current at soft start
[0.5 A/div]
______
[1 V/div]
pin to the “L” level stops operation of all the internal circuits and reduces current consumption
V
ON/OFF
OUT
pin in a floating state because it has the structure shown in Figure 9 and is not pulled up
______
1.5 A
“H”
“L”
3 V
0 V
0 A
pin
ON/OFF
______
Seiko Instruments Inc.
CR Oscillation Circuit
IN
Operation
Figure 9
Table 8
voltage level so that the switching transistor is turned off.
Stop
t [1 ms/div]
VIN
S-8520A33MC (V
VSS
Output voltage
Set value
______
V
SS
IN
: 0 V→4.0 V)
pin, connect it to the VIN pin.
______
pin is at the “H” level. This
______
pin because applying
Rev.9.0
OUT
) to rise
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