MAX16023 Datasheet, PDF (14/17 Pages) Maxim Integrated Products – Battery-Backup Circuits with Regulated Output Voltage

Battery-Backup Circuits with
Regulated Output Voltage
V_IN
R1
C1*
R2
R3
+5V
0.1µF
PFI
V_CC
MAX16023
PFO
( ) ^{VTRIP = VPFT x}
R1 + R2
R2
( ) ( ) ^{VH = VPFT + VPFI - HYS x}
R1 ₊ R1 _{+ 1}
R2 R3
( ) ^{VL = R1 x}
V_{PFT -} V_CC - V_PFT
R2
R3
+ V_PFT
WHERE V_PFT IS THE POWER-FAIL
THRESHOLD VOLTAGE.
GND
TO µP
+5V
PFO
0
V_L V_TRIP V_H
V_IN
*OPTIONAL
Figure 5. Adding Hysteresis to the Power-Fail Comparator
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.
Part Number Table
PART
MAX16023LTAL12+T
MAX16023LTAL18+T
MAX16023LTAL25+T
MAX16023LTAL33+T
MAX16023LTAM12+T
MAX16023LTAM18+T
MAX16023LTAM25+T
MAX16023LTAM33+T
MAX16023LTAT12+T
MAX16023LTAT18+T
MAX16023LTAT25+T
MAX16023LTAS12+T
MAX16023LTAS18+T
MAX16023LTAS25+T
MAX16023LTAR12+T
MAX16023LTAR18+T
MAX16023LTAR25+T
MAX16023LTAZ12+T
OUTPUT
TYPE
RESET REGULATED
THRESHOLD OUTPUT
VOLTAGE VOLTAGE
( V)
(V)
PART
Push-Pull
4.63
Push-Pull
4.63
Push-Pull
4.63
Push-Pull
4.63
Push-Pull
4.38
Push-Pull
4.38
Push-Pull
4.38
Push-Pull
4.38
Push-Pull
3.08
Push-Pull
3.08
Push-Pull
3.08
Push-Pull
2.93
Push-Pull
2.93
Push-Pull
2.93
Push-Pull
2.63
Push-Pull
2.63
Push-Pull
2.63
Push-Pull
2.32
1.2
MAX16024LTBL12+T
1.8
MAX16024LTBL18+T
2.5
MAX16024LTBL25+T
3.3
MAX16024LTBL33+T
1.2
MAX16024LTBM12+T
1.8
MAX16024LTBM18+T
2.5
MAX16024LTBM25+T
3.3
MAX16024LTBM33+T
1.2
MAX16024LTBT12+T
1.8
MAX16024LTBT18+T
2.5
MAX16024LTBT25+T
1.2
MAX16024LTBS12+T
1.8
MAX16024LTBS18+T
2.5
MAX16024LTBS25+T
1.2
MAX16024LTBR12+T
1.8
MAX16024LTBR18+T
2.5
MAX16024LTBR25+T
1.2
MAX16024LTBZ12+T
OUTPUT
TYPE
RESET
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)
Push-Pull
4.63
1.2
Push-Pull
4.63
1.8
Push-Pull
4.63
2.5
Push-Pull
4.63
3.3
Push-Pull
4.38
1.2
Push-Pull
4.38
1.8
Push-Pull
4.38
2.5
Push-Pull
4.38
3.3
Push-Pull
3.08
1.2
Push-Pull
3.08
1.8
Push-Pull
3.08
2.5
Push-Pull
2.93
1.2
Push-Pull
2.93
1.8
Push-Pull
2.93
2.5
Push-Pull
2.63
1.2
Push-Pull
2.63
1.8
Push-Pull
2.63
2.5
Push-Pull
2.32
1.2
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