L1136_11 Datasheet, PDF (8/9 Pages) Unisonic Technologies – HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR

L1136
Preliminary
CMOS IC
„ FUNCTIONAL DESCRIPTION
1. Basic Operation
The UTC L1136‘s block diagram is shown in the following. (Figure 1)
The UTC L1136 has an error amplifier, and it compares the reference voltage (V_ref) with V_fb, which is the output
voltage resistance-divided by feedback resistors R_S and R_F. It supplies the gate voltage necessary to maintain the
constant output voltage which is not influenced by the input voltage and temperature change, to the output
transistor.
2. Output Transistor
For L1136, the output transistor is a P-channel MOSFET with low on-resistance.
In order to protect against inverse current, make sure that V_OUT does not exceed V_IN+0.3V, because of a
parasitic diode between the V_IN and V_OUT pin, when the potential of V_OUT became higher than V_IN.
3. Shutdown Pin (ON/OFF pin)
The shutdown pin is used to turn on and turn off this regulator.
When the ON/OFF pin is set to the shutdown level, the entire internal circuit stops operating. For reducing the
current dissipation, the internal P-channel MOS FET is shut down. The V_OUT pin is set to the V_SS level by the internal
dividing resistor of several hundred kΩ between the V_OUT and VSS pin.
Note: When the ON/OFF pin voltage is in the range of 0.3V~1.0V, the current dissipation increases. The
architecture of the ON/OFF pin can be seen in Figure 2. Since the ON/OFF pin is neither pulled down nor pulled up
internally, do not use it in the floating state.
ON/OFF Pin
“L”: Power off
“H”: Power on
Internal Circuits
Stop
Operate
V_OUT Pin Voltage
V_SS level
Set value
Current Consumption
I_SS2
I_SS1
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