S-8540 Datasheet, PDF (8/36 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
S-8540/8541 Series
Rev.3.2_00
2. S-8540/8541 Series B, D types
Table 6
(Ta = 25 °C,unless otherwise specified)
Parameter
Symbol
Conditions
Measure-
Min.
Typ.
Max.
Units ment
Circuit
Output voltage ^{*1, *2}
V_{OUT (E)}
V_IN = 4.5 V
I_OUT = 120 mA
V_{OUT (S)} V_{OUT (S)} V_{OUT (S)}
× 0.980 = 3.000 × 1.020
V
4
Input voltage
V_IN
−
2.5
−
10.0
V
3
Current consumption 1
I_SS1
V_IN = 4.5 V
100% duty ratio
S-8540/8541B00
S-8540/8541D00
−
−
180
140
300
240
μA
3
Current consumption
during shutdown
EXT pin output current
I_SSS
V_ON/OFF = 0 V
V_OUT = V_{OUT (S)} × 0.95
I_EXTH
V_IN = 10 V, V_EXT = V_IN − 0.2 V
I_EXTL
V_IN = 10 V, V_EXT = 0.2 V
−
−
1.0
μA
3
− 32
− 48
−
mA
3
45
66
−
mA
3
Line regulation
Load regulation
Output voltage
temperature coefficient
ΔV_OUT1
ΔV_OUT2
ΔV_OUT
ΔTa • V_OUT
3.3 ≤ V_IN ≤ 10 V, I_OUT = 120 mA
10 μA ≤ I_OUT ≤ 150 mA
V_IN = V_{OUT (S)} × 1.5, I_OUT = 120 mA
− 40 ≤ Ta ≤ + 85°C
−
30
60
mV
4
−
30
60
mV
4
−
± 100
−
ppm/
°C
4
Oscillation frequency
f_OSC
Measure waveform at
the EXT pin.
S-8540/8541B00
510
600
690
kHz
S-8540/8541D00
255
300
345
4
Maximum duty ratio
MaxDuty Measure waveform at the EXT pin.
100
−
−
%
4
PWM/PFM-control switch
duty ratio ^*3
PFM Duty V_IN = V_{OUT (S)} × 1.5 V, no load
19
29
39
%
4
Current limit detection
voltage
V_SENSE V_IN = 4.5 V, Measure waveform at the EXT pin.
100
125
150
mV
3
SENSE pin input current
Shutdown pin
input voltage
I_SENSE
V_SH
V_SL
V_IN = 4.5 V, V_SENSE = V_IN − 0.1 V
V_IN = 4.5 V, Judge V_{OUT (S)} × 0.98.
V_IN = 4.5 V, Judge CVREF pin "L".
6.7
11.2
16.8
μA
3
2.3
−
−
V
4
−
−
0.3
V
3
Shutdown pin
input leakage current
I_SH
V_IN = 4.5 V, V_ON/OFF = V_OUT
I_SL
V_IN = 4.5 V, V_ON/OFF = 0 V
− 0.1
−
0.1
μA
3
− 0.1
−
0.1
μA
3
Soft-start time
Efficiency
t_SS
Time until V_{OUT (E)} reaches 90% or higher of the
V_{OUT (S)}
7.0
12.0
17.0
ms
4
EFFI
−
−
90
−
%
4
External components:
Coil (L)
:Sumida Corporation CDRH6D28-100
Diode (SD)
:Matsushita Electric Inducstrial Co., Ltd. MA2Q737 (Schottky diode)
Output capacitor (C_OUT) :Nichicon Corporation F93 (16 V, 47 μF, tantalum)
Input capacitor (C_IN)
Transistor (P_SW)
Base resistor (R_b)
Base capacitor (C_b)
:Nichicon Corporation F93 (16 V, 47 μF, tantalum)
:Toshiba Corporation 2SA1213
:100 mΩ
:2200 pF
C_VL
:1.0 μF
C_SS
:0.047 μF
R_SS
:220 kΩ
R_SENSE
:100 mΩ
R_A
:200 kΩ
R_B
:100 kΩ
C_FB
:50 pF
Condition: Connect recommended parts unless otherwise specified. V_IN =4.5 V, I_OUT =120 mA
*1. V_{OUT (S)} : Specified output voltage value, V_{OUT (E)} : Actual output voltage value
*2. The typical value (specified output voltage value) is V_{OUT (S)} = 1 + R_A/R_B = 3.0 V. See “Output Voltage adjustment”.
*3. 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.
8
Seiko Instruments Inc.