FEDL5401A-02
OKI Semiconductor
ML5401A
2) Input Bypass Capacitor
An input capacitor is recommended. A 10µF on the Vdd and Vin pins is a suitable input bypass for most
applications.
3) Output Capacitor
The output capacitor is critical in maintaining regulator stability. The minimum output capacitance required by
the ML5401A is 22µF and it can be increased to 100uF. Any increase of the output capacitance will merely
improve the loop stability and transient response. Also the capacitor ESR range of capacitor is as following:
Capacitor value (uF)
22,33,47,100
ESR(min)
0Ω
ESR(max)
100mΩ
4) Output Voltage selection
The ML5401A is a voltage regulator IC consisting of two voltage regulators, both of which have their own
output voltage identifier pins. The ML5401A has nine different output voltage settings according to below
table. In printer applications,Four voltages in Table 2 are used.
Vid1
1
1
1
F
Vid0
0
1
F
F
Output Voltage
1.2V
1.5V
1.8V
2.5V
Table 2: Output Voltage Selection Codes (F = Float, 1 = Vdd, and 0 = Gnd)
5) Load Regulation
The ML5401A regulates the voltage that appears between its output and ground pins. In some cases, line
resistances can introduce errors to the voltage across the load. To obtain the best load regulation, a few
precautions are needed.
The following figure shows a typical application with Rt1 & Rt2 as line resistances. It is obvious that the Vload
is less than the Vouta by the sum of the voltage drops along the line resistances. In this case, the load
regulation seen at the Rla would be degraded from the data sheet specification. To improve this, the load
should be tied directly to the output terminal on the positive side and directly tied to the ground terminal on the
negative side with short & wide traces.
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