S-8357E50MC-NLJT2G Seiko Instruments, S-8357E50MC-NLJT2G Datasheet - Page 30

• Manufacturer Part Number: S-8357E50MC-NLJT2G
• Description: IC REG CTRL PWM 5.0V SOT23-5
• Manufacturer: Seiko Instruments
• Type: Step-Up (Boost)r

Specifications of S-8357E50MC-NLJT2G

• Internal Switch(s): No
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 5V
• Current - Output: 100mA
• Frequency - Switching: 100kHz
• Voltage - Input: 0.9 ~ 10 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: 5 V
• Input Voltage: 10 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

30
STEP-UP, SUPER-SMALL PACKAGE, 600 kHz, PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8355/56/57/58 Series
1. Inductor
2. Diode
The inductance value (L value) has a strong influence on the maximum output current (I
Figure 17 shows the relationship between the I
The peak current (I
value is decreased, the efficiency falls causing a decline in the current drive capacity for the switching transistor, and
I
The loss of I
certain L value. Further increasing L value decreases the efficiency due to the loss of the direct current resistance of
the coil. I
A higher oscillation frequency allows selection of a lower L value, making the coil smaller.
The recommended inductances are a 22 to 100 μH for B, E, and K types, a 4.7 to 47 μH for F, G, H, J, L, and M
types, 3.0 to 22 μH for N, P and Q types.
Be careful of the allowable inductor current when choosing an inductor. Exceeding the allowable current of the
inductor causes magnetic saturation, much lower efficiency and destruction of the IC chip due to a large current.
Choose an inductor so that I
following equation:
f
Use an external diode that meets the following requirements :
I
OUT
osc
PK
= oscillation frequency, V
• Low forward voltage : V
• High switching speed : 500 ns max.
• Reverse voltage :
• Current rate :
=
decreases.
I 2
OUT
OUT
PK
(
also decreases.
V
f
by the switching transistor decreases by increasing L value and the efficiency becomes maximum at a
OUT
OSC
PK
+
•
Figure 17 L Value vs. I
L
V
) increases by decreasing L value and the stability of the circuit improves and I
D
−
V
IN
V
I
PK
PK
)
D
Coil size :
smaller
Efficiency
decreases
I
I
F
OUT
OUT
PK
≅
(A)
< 0.3 V
does not exceed the allowable current. I
or more
increases
0.4 V.
decreases
+ V
F
or more
CDRH6D28, V
Seiko Instruments Inc.
4.7
OUT
F, G, H, J, L and M types
OUT
Recommended range
Characteristics, L Value vs. η Characteristics
and η dependency on L of S-8355/56/57/58 series.
L value (μH)
OUT
= 5.0 V, V
I
OUT
η
IN
47
= 3.0 V
PK
Efficiency
decreases
I
I
Coil size : bigger
in discontinuous mode is calculated by the
OUT
PK
decreases
decreases
OUT
) and efficiency (η).
OUT
Rev.7.0
increases. If L
(17)
_00