s-8424a Seiko Instruments Inc., s-8424a Datasheet - Page 26

• Manufacturer Part Number: s-8424a
• Description: Battery Backup Switching Ic
• Manufacturer: Seiko Instruments Inc.

2. Load Transient Response Based on Output Current Fluctuation
26
BATTERY BACKUP SWITCHING IC
S-8424A Series
The overshoot and undershoot are caused in the output voltage if the output current fluctuates between 10 μ A and
50 mA (V
variation due to the output current. Figure 19 shows the test circuit for reference. The latter half of this section
describes ringing waveform and parameter dependency.
Figure 20 shows the ringing waveforms at the VOUT pin and Figure 21 shows the ringing waveforms at the VRO
pin due to the load variation, respectively.
VOUT pin
VRO pin
Figure 18 Output Voltage Variation due to
Output
current
Output
current
Output voltage
Output current
Output voltage
Output current
(20 mV/div)
(50 mV/div)
RO
is between 10 μ A and 30 mA) while the input voltage is constant. Figure 18 shows the output voltage
Output Current
50 mA
30 mA
50 mA
Figure 20 Ringing Waveform due to Load Variation (VOUT Pin)
Figure 21 Ringing Waveform due to Load Variation (VRO Pin)
10 μA
10 μA
t (500 ms/div)
t (20 ms/div)
10 μA
Ov ershoot
Seiko Instruments Inc.
Undershoot
VIN
S-8424A
Series
V
VSS
IN
V
= 6.0 V, C
IN
Figure 19 Test Circuit
10 μA
=6.0 V, C
VOUT
10 μA
50 mA
30 mA
t (50 μs/div)
C
OUT
OU T
RO
t (50 μs/div)
= 22 μF, Ta = 25°C
=22 μF, Ta=25°C
Oscilloscope
Rev.2.2
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