S-87X_1 Datasheet, PDF (38/53 Pages) Seiko Instruments Inc – HIGH WITHSTAND-VOLTAGE VOLTAGE REGULATOR WITH RESET FUNCTION

HIGH WITHSTAND-VOLTAGE VOLTAGE REGULATOR WITH RESET FUNCTION
S-87x Series
Rev.7.2_00
2. Load transient response characteristics due to load current fluctuation
An overshoot and an undershoot are caused in the output voltage if the load current is changed from
50 μA to 40 mA while the input voltage is kept constant. Figure 31 shows the output voltage fluctuation
due to a change in the load current. The measuring circuit is shown in Figure 32 for reference. The
latter half of this section describes ringing waveform and parameter dependency.
50 μA
Load current
40 mA
Output Voltage deviation
Overshoot
Undershoot
Figure 31 Output voltage fluctuation due to a change in the load current
Power
supply
VIN
10 μF −+
S-87x
Series
VOUT
VSS
R₁^*1 R₀^*2
+− _CL^*3
Oscilloscope
10:1 probe
*1.
R₁=
VOUT [V]
50 μA
[Ω]
*2.
R₀=
VOUT [V]
40 mA
[Ω]
*3. AL electrolytic capacitor
Figure 32 Measuring circuit
Series
S-8750xxx,
S-8730xxx
Table 22 Parameter dependency due to load current fluctuation
Parameter
Load current (I_OUT)
Load capacitance (C_L)
Power supply voltage (V_IN)
Temperature (Ta)
Conditions
10 to 60 mA, C_L=10 μF
1 to 47 μF, I_OUT=40 mA
(V_OUT+1) to 24 V
−40 °C to +85 °C
Method to decrease Method to decrease
overshoot
undershoot
Decrease
Decrease
Increase
Increase
Increase
Increase
Low temperature Low temperature
38
Seiko Instruments Inc.