LP3971
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
Symbol
V
IN
I
OUT
Parameter
Operational Voltage Range
Backup Battery Charging Current
Conditions
Voltage at V
IN
V
IN
= 3.6V, Backup_Bat = 2.5V,
Backup Battery Charger Enabled
V
IN
= 5.0V Backup Battery Charger
Enabled. Programmable
Backup_Bat = 0V, Backup Battery
Charger Enabled
I
OUT
≤
50 µA, V
OUT
= 3.15V
V
OUT
+ 0.4
≤
V
BATT
= V
IN
≤
5.0V
f
<
10 kHz
I
OUT
<
50 µA
0 µA
≤
I
OUT
≤
100 µA
5
2.91
Min
3.3
190
Typ
Max
5.5
Units
V
µA
V
OUT
Charger Termination Voltage
Backup Battery Charger Short
Circuit Current
3.1
9
15
V
mA
dB
PSRR
Power Supply Ripple Rejection
Ratio
Quiescent Current
Output Capacitance
Output Capacitor ESR
I
Q
C
OUT
25
0.1
500
µA
µF
MΩ
Logic Inputs and Outputs DC Operating Conditions
Symbol
V
IL
V
IH
Parameter
Low Level Input Voltage
High Level Input Voltage
Conditions
Logic Inputs (SYS_EN, PWR_EN, SYNC, nRSTI, PWR_ON, nTEST_JIG, SPARE and GPI’s)
Min
V
RTC
−0.5V
−1
Conditions
Load = +0.2 mA = I
OL
Max
Load = −0.1 mA = I
OL
Max
V
ON
= V
IN
Conditions
Programmable via Serial Interface
Default = 2.8V
Load = +0.4 mA = I
OL
Max
Load = −0.2 mA = I
OH
Max
V
RTC
−0.5V
+5
Min
2.4
Typ
2.8
V
RTC
−0.5V
+5
Max
3.4
0.5
Min
+1
Max
0.5
Max
0.5
Units
V
V
µA
Units
V
V
µA
Units
V
V
V
µA
I
LEAK
Input Leakage Current
Logic Outputs (nRSTO, EXT_WAKEUP and GPO’s)
Symbol
V
OL
V
OH
Parameter
Output Low Level
Output High Level
I
LEAK
Output Leakage Current
Logic Output (nBATT_FLT)
Symbol
Parameter
nBATT_FLT Threshold Voltage
V
OL
V
OH
I
LEAK
Output Low Level
Output High Level
Input Leakage Current
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