Part number table, Operation without a backup power source, Replacing the backup battery – Rainbow Electronics MAX16024 User Manual
Page 14: Negative-going v, Transients, Capacitor selection and regulator stability
MAX16023/MAX16024
Operation Without a Backup
Power Source
The MAX16023/MAX16024 provide battery-backup
functions. If a backup power source is not used, con-
nect BATT to GND.
Replacing the Backup Battery
When V
CC
is above V
TH
, the backup power source can
be removed without danger of triggering a reset pulse.
The device does not enter battery-backup mode when
V
CC
stays above the reset threshold voltage.
Negative-Going V
CC
Transients
The MAX16023/MAX16024 are relatively immune to
short duration, negative-going V
CC
transients.
Resetting the µP when V
CC
experiences only small
glitches is usually not desirable. A 0.1µF bypass
capacitor mounted close to the V
CC
pin provides addi-
tional transient immunity.
Capacitor Selection and
Regulator Stability
For stable operation, connect a low-ESR 10µF (min) out-
put capacitor from OUT to GND. To reduce noise and
improve load-transient response and power-supply rejec-
tion, use larger output capacitor values.
Battery-Backup Circuits with
Regulated Output Voltage
14
______________________________________________________________________________________
MAX16023
0.1
μF
GND
PFI
PFO
R2
R1
R3
V
CC
V
H
=
(
V
PFT
+ V
PFT - HYS
)
x
(
+
+ 1
)
R1
R2
R1
R3
V
L
= R1 x
(
-
)
+ V
PFT
V
PFT
R2
V
CC
- V
PFT
R3
WHERE V
PFT
IS THE POWER-FAIL
THRESHOLD VOLTAGE.
*OPTIONAL
+5V
V
IN
C1*
TO
μP
PFO
0
+5V
V
TRIP
V
L
V
H
V
IN
V
TRIP
= V
PFT
x
( )
R1 + R2
R2
Figure 5. Adding Hysteresis to the Power-Fail Comparator
Part Number Table
PART
OUTPUT
TYPE
R ESET
T H R ESH O L D
VO L T A G E
( V)
REGUL ATED
OU TPU T
VO LTA GE
( V)
PART
OUTPUT
TYPE
R ESET
T H R ESH O L D
VO L T A G E
( V)
R EG U L A T ED
O U T PU T
VO L T A G E
( V)
MAX16023LTAL12+T
Push-Pull
4.63
1.2
MAX16024LTBL12+T
Push-Pull
4.63
1.2
MAX16023LTAL18+T
Push-Pull
4.63
1.8
MAX16024LTBL18+T
Push-Pull
4.63
1.8
MAX16023LTAL25+T
Push-Pull
4.63
2.5
MAX16024LTBL25+T
Push-Pull
4.63
2.5
MAX16023LTAL33+T
Push-Pull
4.63
3.3
MAX16024LTBL33+T
Push-Pull
4.63
3.3
MAX16023LTAM12+T
Push-Pull
4.38
1.2
MAX16024LTBM12+T
Push-Pull
4.38
1.2
MAX16023LTAM18+T
Push-Pull
4.38
1.8
MAX16024LTBM18+T
Push-Pull
4.38
1.8
MAX16023LTAM25+T
Push-Pull
4.38
2.5
MAX16024LTBM25+T
Push-Pull
4.38
2.5
MAX16023LTAM33+T
Push-Pull
4.38
3.3
MAX16024LTBM33+T
Push-Pull
4.38
3.3
MAX16023LTAT12+T
Push-Pull
3.08
1.2
MAX16024LTBT12+T
Push-Pull
3.08
1.2
MAX16023LTAT18+T
Push-Pull
3.08
1.8
MAX16024LTBT18+T
Push-Pull
3.08
1.8
MAX16023LTAT25+T
Push-Pull
3.08
2.5
MAX16024LTBT25+T
Push-Pull
3.08
2.5
MAX16023LTAS12+T
Push-Pull
2.93
1.2
MAX16024LTBS12+T
Push-Pull
2.93
1.2
MAX16023LTAS18+T
Push-Pull
2.93
1.8
MAX16024LTBS18+T
Push-Pull
2.93
1.8
MAX16023LTAS25+T
Push-Pull
2.93
2.5
MAX16024LTBS25+T
Push-Pull
2.93
2.5
MAX16023LTAR12+T
Push-Pull
2.63
1.2
MAX16024LTBR12+T
Push-Pull
2.63
1.2
MAX16023LTAR18+T
Push-Pull
2.63
1.8
MAX16024LTBR18+T
Push-Pull
2.63
1.8
MAX16023LTAR25+T
Push-Pull
2.63
2.5
MAX16024LTBR25+T
Push-Pull
2.63
2.5
MAX16023LTAZ12+T
Push-Pull
2.32
1.2
MAX16024LTBZ12+T
Push-Pull
2.32
1.2