Datasheet

LP3972
SNVS468K –SEPTEMBER 2006–REVISED MAY 2013 www.ti.com
LDO RTC
Unless otherwise noted, V
IN
= 3.6V, C
IN
= 1.0 µF, C
OUT
= 0.47 µF, C
OUT
(V
RTC
) = 1.0 µF ceramic. Typical values and limits
appearing in normal type apply for T
J
= 25°C. Limits appearing in boldface type apply over the entire junction temperature
range for operation, −40°C to +125°C
(1)(2)(3)(4)
Symbol Parameter Test Conditions Min Typ Max Unit
V
OUT
Accuracy Output Voltage Accuracy V
IN
Connected, Load Current = 1 mA 2.632 2.8 2.968 V
ΔV
OUT
Line Regulation V
IN
= (V
OUT
nom + 1.0V) to 5.5V
(5)
0.15 %/V
Load Current = 1 mA
Load Regulation From Main Battery 0.05
Load Current = 1 mA to 30 mA
%/mA
From Backup Battery, V
IN
= 3.0V 0.5
Load Current = 1 mA to 10 mA
I
SC
Short Circuit Current Limit From Main Battery 100
V
IN
= V
OUT
+0.3V to 5.5V
mA
From Backup Battery 30
V
IN
- V
OUT
Dropout Voltage Load Current = 10 mA 375 mV
I
Q
_Max Maximum Quiescent Current I
OUT
= 0 mA 30 µA
TP1 RTC LDO Input Switched from V
IN
Falling 2.9 V
Main Battery to Backup Battery
TP2 RTC LDO Input Switched from V
IN
Rising 3.0 V
Backup Battery to Main Battery
C
O
Output Capacitor Capacitance for Stability 0.7 1.0 µF
ESR 5 500 mΩ
(1) All voltages are with respect to the potential at the GND pin.
(2) All limits specified at room temperature (standard typeface) and at temperature extremes (bold typeface). All room temperature limits are
production tested, ensured through statistical analysis or ensured by design. All limits at temperature extremes are ensured via
correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level
(AOQL).
(3) Dropout voltage is the input-to-output voltage difference at which the output voltage is 100 mV below its nominal value.
(4) LDO_RTC voltage can track LDO3 voltage. LP3972 has a tracking function (nIO_TRACK). When enabled, LDO_RTC voltage will track
LDO3 voltage within 200mV down to 2.8V when LDO3 is enabled
(5) V
IN
minimum for line regulation values is 2.7V for LDOs 1–3 and 1.8V for LDOs 4 and 5. Condition does not apply to input voltages
below the minimum input operating voltage.
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