S-8540 Datasheet, PDF (7/36 Pages) Seiko Instruments Inc – STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER

STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.3.2_00
S-8540/8541 Series
„ Electrical Characteristics
1. S-8540/8541 Series A, C types
Table 5
(Ta = 25 °C, unless otherwise specified)
Measure-
Parameter
Symbol
Conditions
Min. Typ. Max. Units ment
Circuit
Output voltage ^*1
Input voltage
Current consumption 1
V_{OUT (E)}
V_IN = V_{OUT (S)} × 1.5
I_OUT = 120 mA
V_{OUT (S)}
× 0.980
V_{OUT (S)}
V_{OUT (S)}
× 1.020
V
2
V_IN
−
2.5
−
10.0
V
1
I_SS1
V_IN = V_{OUT (S)} × 1.5
100 % duty ratio
S-8540/8541Axx
S-8540/8541Cxx
−
180
300
μA
1
−
140 240
Current consumption
during shutdown
EXT pin output current
Line regulation
Load regulation
Output voltage temperature
coefficient
I_SSS
I_EXTH
I_EXTL
ΔV_OUT1
ΔV_OUT2
ΔV_OUT
ΔTa • V_OUT
V_ON/OFF = 0 V
V_OUT = V_{OUT (S)} × 0.95
V_IN = 10 V, V_EXT = V_IN − 0.2 V
V_IN = 10 V, V_EXT = 0.2 V
V_{OUT (S)} × 1.1 ≤ V_IN ≤ 10 V, I_OUT = 120 mA
V_IN = V_{OUT (S)} × 1.5, 10 μA ≤ I_OUT ≤ 150 mA
V_IN = V_{OUT (S)} × 1.5, I_OUT = 120 mA
− 40 ≤ Ta ≤ + 85 °C
−
−
1.0
μA
1
− 32 − 48
−
mA
1
45
66
−
mA
1
−
30
60
mV
2
−
30
60
mV
2
−
± 100
−
ppm/
°C
2
Oscillation frequency
Measure waveform at the EXT S-8540/8541Axx
f_OSC
pin.
S-8540/8541Cxx
510
600
690
kHz
2
255
300 345
Maximum duty ratio
MaxDuty Measure waveform at the EXT pin.
100
−
−
%
2
PWM/PFM-control switch
duty ratio ^*2
PFMDuty V_IN = V_{OUT (S)} × 1.5, no load
19
29
39
%
2
Current limit detection
voltage
V_SENSE
V_IN = V_{OUT (S)} × 1.5,
Measure waveform at the EXT pin.
100
125 150 mV
1
SENSE pin input current
Shutdown pin
input voltage
Shutdown pin
input leakage current
Soft-start time
Efficiency
I_SENSE
V_IN = V_{OUT (S)} × 1.5, V_SENSE = V_IN − 0.1 V
6.7
11.2 16.8 μA
1
V_SH
V_IN = V_{OUT (S)} × 1.5, Judge V_OUT(S) × 0.98.
2.3
−
−
V
2
V_SL
V_IN = V_{OUT (S)} × 1.5, Judge CVREF pin "L".
−
−
0.3
V
1
I_SH
V_IN = V_{OUT (S)} × 1.5, V_ON/OFF = V_OUT
− 0.1
−
0.1
μA
1
I_SL
V_IN = V_{OUT (S)} × 1.5, V_ON/OFF = 0 V
− 0.1
−
0.1
μA
1
t_SS
Time until V_{OUT (E)} reaches 90% or higher of the V_OUT(S) 7.0
12.0 17.0 ms
2
EFFI
−
−
90
−
%
2
External components
Coil (L)
Diode (SD)
Output capacitor (C_OUT)
Input capacitor (C_IN)
Transistor (P_SW)
Base resistor (R_b)
Base capacitor (C_b)
C_VL
C_SS
R_SS
R_SENSE
:Sumida Corporation. CDRH6D28-100
:Matsushita Electric Inducstrial Co., Ltd. MA2Q737 (Schottky diode)
:Nichicon Corporation F93 (16 V, 47 μF, tantalum)
:Nichicon Corporation F93 (16 V, 47 μF, tantalum)
:Toshiba Corporation 2SA1213
:100 mΩ
:2200 pF
:1.0 μF
:0.047 μF
:220 kΩ
:100 mΩ
Condition: Recommended parts are used unless otherwise specified.
V_IN =V_{OUT (S)} ×1.5 V, I_OUT = 120 mA (When V_{OUT (S)} ≤ 1.6 V, then V_IN = 2.5 V)
*1. V_{OUT (S)} : Specified output voltage value, V_{OUT (E)} : Actual output voltage value
*2. Applied to the S-8541 series only
Caution 1. Line regulation and load regulation may change greatly due to GND wiring when V_IN is high.
2. In the S-8540 series (PWM control), a state in which the duty ratio 0% continues for several
clocks may occur when the input voltage is high and the output current is low. In this case,
the operation changes to the pseudo PFM mode, but the ripple voltage hardly increases.
Seiko Instruments Inc.
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