S-8340A25AFT-T2-X Datasheet, PDF (14/55 Pages) Seiko Instruments Inc – SWITCHABLE SWITCHING REGULATOR CONTROLLER

STEP-UP, 600 kHz, PWM CONTROL OR PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8340/8341 Series
Rev.4.0_01
External parts
Coil :
Sumida Corporation CD54 (10 μH)
Diode :
Matsushita Electronic Industrial Co., Ltd. MA735 (Schottky type)
Capacitor :
Nichicon Corporation F93 (16 V, 47 μF, tantalum type)
Transistor :
Sanyo Electric Co., Ltd. 2SD1628G
Base resistor (Rb) : 1.0 kΩ
Base capacitor (Cb) : 2200 pF (ceramic type)
CVREF :
0.01 μF
CSS :
4700 pF
RFB1 :
300 kΩ
RFB2 :
100 kΩ
CFB :
50 pF
The ON/OFF pin is connected to the VOUT pin unless otherwise specified.
Connect the SENSE pin to the VSS pin.
*1. VOUT(E) : Actual output voltage value : Output voltage value when IOUT = 80 mA and VIN = 2.4 V is applied.
The
Typ.
value
(set
output
voltage
value)
is
1
+
300
100
kΩ
kΩ
[V]
*2. The change of output voltage with temperature [mV/°C] is calculated from the following formula. However, the
temperature change rates for RFB1 and RFB2 are assumed to be the same.
ΔVOUT
ΔTa
[mV/°C]
=
(1
+
R_FB1
R_FB2
)_×
ΔVOUT
ΔTa • VOUT
[ppm/°C]
÷ 1000
(Change of output voltage (Set output
(Output voltage temperature
with temperature)
voltage value) coefficient)
Caution
The S-8340/8341 Series steps up from VDD = 0.9 V. However, 2.5 V or more for VDD is recommended to
stabilize the output voltage and oscillation frequency. If VDD is taken from VIN or other power sources,
instead of VOUT, VDD should be 2.5 V or more. However, if VDD is other than 4.0 V, note that the output
voltage accuracy of ±2.0% is not guaranteed due to dependency of output voltage on VDD. In particular,
accuracy of output voltage is degraded significantly when the VDD voltage is 6.0 V or more. Therefore,
do not use this IC when the VDD voltage is 6.0 V or more. If VDD of 2.5 V or more is applied, increase
power supply so that VDD becomes 2.5 V or more within the soft-start time (6.0 ms).
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