BD37201NUX Datasheet, PDF (3/22 Pages) Rohm – Ultra Low Noise Low Dropout Regulator for Audio System

BD37201NUX
Description of Block
1. Enable
Assuming EN terminal is set to L, the IC can be set to standby state. In standby state, the output is OFF and since it will
be in static state, the power consumption can be reduced.
2. Rising ,Falling, and EN Controlled Timing
2.45V(typ)
2.30V(typ)
VIN
0V
EN
0V
UVLO
(internal signalL)
1.6V(typ)
1.4V(typ)
1.6V(typ)
1.4V(typ)
VOUT DISABLE
(internal signal) L
1.0V
85%
85%
VOUT
0V
1.0V
85%
85%
BC
0V
9ms
9ms
EN ON _UVLO
EN OFF
EN ON
UVLO ^{EN OFF}
time
release
detect
Figure 4. The Waveform During VIN/EN Rising and Falling
(When at BC Capacitor 1µF and Output 1V Settings)
It will operate if EN is ON and UVLO (Under Voltage Lockout) is released. In addition, when EN is OFF or UVLO is
detected, the regulator operation stops.
The maximum slew rate of input voltage has to be set under 1V/µs.
3. Soft Start Function
In BD37201NUX, there exists a function that limits the rising speed of output when EN rises by the capacitor connected
to BC due to decrease of inrush current of output. The rising speed depends on the capacitance value connected to BC
and on the output programmed voltage. It is about 9ms (Typ) if capacitance is 1µF and output programmed voltage is 1V,
and almost 30ms (Typ) if output programmed voltage is set to 3.35V.
4. REFAMP
REFAMP settle its output voltage through the reference voltage 1.0V (Typ) and external resistors.
5. BC Terminal
Noise at the output voltage of REFAMP will be reduced because of the internal resistor and the external BC capacitor. In
addition to it, the external BC capacitor also has a soft start function so the rising speed can be adjusted by this value.
The higher value of capacitor will decrease the noise but the softstart time will be longer.
6. ERRAMP
The ERRAMP outputs the voltage set in REFAMP at closed gain 1 time. VS terminal must be connected to OUT by all
means. In addition, VS terminal can decrease a voltage drop by the pattern resistance on the OUT course by returning
the voltage from the supply point.
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TSZ22111 • 15 • 001
3/18
TSZ02201-0V3V0A600100-1-2
18.Apr.2016 Rev.001