LP3971 Datasheet, PDF (10/42 Pages) National Semiconductor (TI) – POWER MANAGEMENT UNIT FOR ADVANCED APPLICATION PROCESSORS

Back-Up Charger Electrical Characteristics
Unless otherwise noted, V_IN = V_BATT = 3.6V. Typical values and limits appearing in normal type apply for T_J = 25˚C. Limits ap-
pearing in boldface type apply over the entire junction temperature range for operation, −40˚C to +125˚C. (Notes 2, 6) and
(Note 8).
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V_IN
Operational Voltage Range
Voltage at V_IN
3.3
5.5
V
I_OUT
Backup Battery Charging Current V_IN = 3.6V, Backup_Bat = 2.5V,
190
µA
Backup Battery Charger Enabled
(Note 8)
V_OUT
Charger Termination Voltage
V_IN = 5.0V Backup Battery Charger 2.91
3.1
V
Enabled. Programmable
Backup Battery Charger Short
Backup_Bat = 0V, Backup Battery
9
mA
Circuit Current
Charger Enabled
PSRR Power Supply Ripple Rejection
I_OUT ≤ 50 µA, V_OUT = 3.15V
15
dB
Ratio
V_OUT + 0.4 ≤ V_BATT = V_IN ≤ 5.0V
f < 10 kHz
I_Q
C_OUT
Quiescent Current
Output Capacitance
Output Capacitor ESR
I_OUT < 50 µA
0 µA ≤ I_OUT ≤ 100 µA
25
µA
0.1
µF
5
500
MΩ
Logic Inputs and Outputs DC Operating Conditions (Note 2)
Logic Inputs (SYS_EN, PWR_EN, SYNC, nRSTI, PWR_ON, nTEST_JIG, SPARE and GPI’s)
Symbol
V_IL
V_IH
Parameter
Low Level Input Voltage
High Level Input Voltage
I_LEAK
Input Leakage Current
Logic Outputs (nRSTO, EXT_WAKEUP and GPO’s)
Conditions
Min
V_RTC
−0.5V
−1
Max
0.5
+1
Units
V
V
µA
Symbol
V_OL
V_OH
Parameter
Output Low Level
Output High Level
I_LEAK
Output Leakage Current
Logic Output (nBATT_FLT)
Conditions
Load = +0.2 mA = I_OL Max
Load = −0.1 mA = I_OL Max
V_ON = V_IN
Min
V_RTC
−0.5V
Max
0.5
+5
Units
V
V
µA
Symbol
Parameter
Conditions
Min
Typ
nBATT_FLT Threshold Voltage
Programmable via Serial Interface
2.4
2.8
Default = 2.8V
V_OL
Output Low Level
V_OH
Output High Level
Load = +0.4 mA = I_OL Max
Load = −0.2 mA = I_OH Max
V_RTC
−0.5V
I_LEAK
Input Leakage Current
Max
Units
3.4
V
0.5
V
V
+5
µA
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