TC1301B-DAAVUATR Datasheet, PDF (12/28 Pages) Microchip Technology – Dual LDO with Microcontroller RESET Function

TC1301A/B
3.0 TC1301A PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1: TC1301A PIN FUNCTION TABLE
Pin No.
Name
Function
1
RESET Push-pull output pin that will remain low while V_DET is below the reset threshold and for
300 ms after V_DET rises above the reset threshold.
2
V_OUT1 Regulated output voltage #1 capable of 300 mA.
3
GND Circuit ground pin.
4
Bypass Internal reference bypass pin. A 10 nF external capacitor can be used to further reduce
output noise and improve PSRR performance.
5
SHDN2 Output #2 shutdown control Input.
6
V_OUT2 Regulated output voltage #2 capable of 150 mA.
7
V_IN
Unregulated input voltage pin.
8
V_DET Input pin for Voltage Detector (V_DET).
3.1 RESET Output Pin
The push-pull output pin is used to monitor the voltage
on the V_DET pin. If the V_DET voltage is less than the
threshold voltage, the RESET output will be held in the
low state. As the V_DET pin rises above the threshold,
the RESET output will remain in the low state for
300 ms and then change to the high state, indicating
that the voltage on the V_DET pin is above the threshold.
3.2 Regulated Output Voltage #1
(V_OUT1)
Connect V_OUT1 to the positive side of the V_OUT1
capacitor and load. It is capable of 300 mA maximum
output current. V_OUT1 output is available when V_IN is
available; there is no pin to turn it OFF. See TC1301B
if ON/OFF control of V_OUT1 is desired.
3.3 Circuit Ground Pin (GND)
Connect GND to the negative side of the input and
output capacitor. Only the LDO internal circuitry bias
current flows out of this pin (200 µA maximum).
3.4 Reference Bypass Input
By connecting an external 10 nF capacitor (typical) to
the bypass input, both outputs (V_OUT1 and V_OUT2) will
have less noise and improved Power Supply Ripple
Rejection (PSRR) performance. The LDO output
voltage start-up time will increase with the addition of
an external bypass capacitor. By leaving this pin
unconnected, the start-up time will be minimized.
3.5 Output Voltage #2 Shutdown
(SHDN2)
ON/OFF control is performed by connecting SHDN2 to
its proper level. When the input of this pin is connected
to a voltage less than 15% of V_IN, V_OUT2 will be OFF. If
this pin is connected to a voltage that is greater than
45% of V_IN, V_OUT2 will be turned ON.
3.6 Regulated Output Voltage #2
(V_OUT2)
Connect V_OUT2 to the positive side of the V_OUT2
capacitor and load. This pin is capable of a maximum
output current of 150 mA. V_OUT2 can be turned ON and
OFF using SHDN2.
3.7 Unregulated Input Voltage Pin
(V_IN)
Connect the unregulated input voltage source to V_IN. If
the input voltage source is located more than several
inches away, or is a battery, a typical input capacitance
of 1 µF to 4.7 µF is recommended.
3.8 Input Pin for Voltage Detector
(V_DET)
The voltage on the input of V_DET is compared with the
preset V_DET threshold voltage. If the voltage is below
the threshold, the RESET output will be low. If the
voltage is above the V_DET threshold, the RESET output
will be high after the RESET time period. The I_DET
supply current is typically 9 µA at room temperature,
with V_DET = 3.8V.
DS21798C-page 12
© 2008 Microchip Technology Inc.