19-4249; Rev 0; 8/08
Battery-Backup Circuits with
Regulated Output Voltage
General Description
The MAX16023/MAX16024 low-power battery-backup cir-
cuits with a regulated output are capable of delivering up
to 100mA output current. The MAX16023/MAX16024
include a low-dropout regulator, a microprocessor (µP)
reset circuit, and a battery switchover circuit. Additional
available features include a manual reset, a power-fail
comparator, and a battery-on indicator. These devices
reduce the number of external components to minimize
board space and improve reliability.
The MAX16023/MAX16024 are ideally suited for provid-
ing power for backing up critical memory such as static
random-access memory (SRAM) or real-time clocks
(RTCs). The regulated output is powered by V
CC
when it
is present and switches over to the backup power dur-
ing brownout. The MAX16023/MAX16024 accept an
input voltage from 1.53V to 5.5V and provide fixed stan-
dard output voltages of 1.2V, 1.8V, 2.5V, 3.0V, and 3.3V.
The MAX16024 offers the ability to externally set the out-
put voltage using a resistive divider. All outputs are
available with push-pull or open-drain configurations.
The MAX16023 offers a power-fail comparator for monitor-
ing an additional voltage or for providing an early power-
fail warning. Another feature includes a manual-reset input
(MAX16023/MAX16024). The MAX16024 also features
a battery-on indicator and chip-enable gating function.
The MAX16023/MAX16024 are offered in 8- and 10-pin
TDFN packages and are fully specified from -40°C to
+85°C temperature range.
♦
100mA Low-Dropout Regulator
♦
Factory-Trimmed and Adjustable Output Voltages
♦
1.53V to 5.5V Operating Voltage Range
♦
Low-Power Consumption: 4µA (typ)
♦
Power-Fail Comparators for Monitoring Voltages
Down to 0.6V
♦
Battery-On Indicator
♦
Battery Freshness Seal
♦
On-Board Gating of CE Signals, 1.5ns
Propagation Delay (MAX16024)
♦
Debounced Manual-Reset Input
♦
145ms (min) Reset Timeout Period
♦
Tiny 8-Pin and 10-Pin TDFN Packages
♦
UL
®
Certified to Conform to IEC 60950-1
Features
♦
System Monitoring for 5V, 3.3V, 3V, 2.5V, or 1.8V
Power-Supply Voltages
MAX16023/MAX16024
Ordering Information
PART
MAX16023_TA_
_ _+T
MAX16024_TB_
_ _+T
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 TDFN-EP*
10 TDFN-EP*
Applications
Main/Backup Power for RTCs/SRAM
Industrial Controls
GPS Systems
Set-Top Boxes
Point-of-Sale Equipment
Portable/Battery Equipment
UL is a registered trademark of Underwriters Laboratories, Inc.
The first placeholder “_” designates reset output options. A letter
“L” in this placeholder indicates a push-pull output and letter “P”
indicates an open-drain output. The next placeholder “_” desig-
nates the reset threshold (Table 1). The last two placeholders
“_ _” designate output voltage (Table 2). For the MAX16024 with
adjustable output voltage version, there are no last two place-
holders.
+Denotes
a lead-free/RoHS-compliant package.
T = Tape and reel.
*EP
= Exposed pad.
Pin Configurations
BATT ON
6
*EP
2
V
CC
3
BATT
4
MR
5
SET
CEOUT
RESET
RESET
8
GND
GND
7
OUT
OUT
9
PFO
5
8
7
6
10
MAX16023
MAX16024
*EP
+
1
V
CC
2
BATT
3
MR
+
1
CEIN
4
PFI
TDFN
*EP = EXPOSED PAD
TDFN
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Battery-Backup Circuits with
Regulated Output Voltage
MAX16023/MAX16024
ABSOLUTE MAXIMUM RATINGS
V
CC
, BATT, OUT to GND..........................................-0.3V to +6V
RESET, PFO,
BATT ON (all open drain)
to GND..................................................................-0.3V to +6V
RESET, PFO,
BATT ON (all push-pull)
to GND .................................................-0.3V to (V
OUT
+ 0.3V)
PFI,
CEIN, CEOUT
to GND.......................-0.3V to (V
OUT
+ 0.3V)
MR
to GND .................................................-0.3V to (V
CC
+ 0.3V)
Input Current
V
CC
Peak Current.....................................................................1A
V
CC
Continuous Current ...............................................250mA
BATT Peak Current .......................................................500mA
BATT Continuous Current ...............................................70mA
Output Current
OUT Short Circuit to GND Duration ....................................10s
RESET,
BATT ON,
CEOUT..............................................20mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin TDFN (derate 24.4mW/°C above +70°C) .........1951mW
10-Pin TDFN (derate 24.4mW/°C above +70°C) .......1951mW
Thermal Resistance (Note 1)
θ
JA
(8-Pin and 10-Pin TDFN)........................................41°C/W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
CC
= 1.53V to 5.5V, V
BATT
= 3V, reset not asserted, T
A
= T
J
= -40°C to +85°C, C
OUT
= 10µF, unless otherwise noted. Typical val-
ues are at T
A
= T
J
= +25°C.) (Note 2)
PARAMETER
Operating Voltage Range
SYMBOL
V
CC,
V
BATT
(Note 3)
LDO = 1.2V
LDO = 1.8V
V
CC
= LDO + 0.5V,
no load
Supply Current
I
CC
V
CC
= LDO + 0.5V,
I
OUT
= 20mA
LDO = 2.5V
LDO = 3V
LDO = 3.3V
LDO = 1.2V
LDO = 1.8V
LDO = 2.5V
LDO = 3V
LDO = 3.3V
Supply Current in Battery-Backup
Mode
BATT Standby Current
SET Reference Voltage
SET Input Leakage Current
Output Voltage Range
V
OUT
V
SET
I
BATT
V
CC
= 0, V
BATT
= 3V,
no dropout, no load
V
CC
> V
BATT
+ 0.2V
MAX16024_TB_, V
CC
= 2.2V
MAX16024_TB_, SET = 1.2V
MAX16024_TB_, V
CC
> V
OUT
LDO = 1.2V
LDO = 1.8V
Output Voltage Accuracy
I
OUT
= 1mA
LDO = 2.5V
LDO = 3V
LDO = 3.3V
-0.01
1.144
-20
1.8
1.145
1.704
2.368
2.837
3.114
1.2
1.8
2.5
3
3.3
1.2
CONDITIONS
MIN
1.53
4.3
4.7
5.2
5.5
5.7
16
16
16
17
17
3.5
TYP
MAX
5.5
6
7
7.5
8
8
20
21
18.1
18.6
19
5.26
+0.01
1.272
+20
5.25
1.270
1.900
2.634
3.165
3.482
V
µA
µA
V
nA
V
µA
UNITS
V
2
_______________________________________________________________________________________
Battery-Backup Circuits with
Regulated Output Voltage
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 1.53V to 5.5V, V
BATT
= 3V, reset not asserted, T
A
= T
J
= -40°C to +85°C, C
OUT
= 10µF, unless otherwise noted. Typical val-
ues are at T
A
= T
J
= +25°C.) (Note 2)
PARAMETER
Line Regulation
Load Regulation
SYMBOL
CONDITIONS
V
CC
= (V
OUT
+ 1V) to (V
OUT
+ 2V),
I
OUT
= 1mA
V
CC
= V
OUT
+ 1V, I
OUT
= 1mA to 2mA
LDO = 1.2V
LDO = 1.8V
Dropout Voltage
I
OUT
= 50mA
(Note 4)
LDO = 2.5V
LDO = 3V
LDO = 3.3V
Output Current Limit
Battery Freshness Leakage
Current
RESET OUTPUT (RESET)
Reset Threshold
V
CC
Falling to Reset Delay
Reset Timeout Period
RESET
Output Low Voltage
RESET
Output High Voltage
(Push-Pull Output)
RESET
Output Leakage Current
(Open-Drain Output)
POWER-FAIL COMPARATOR (PFI,
PFO)
PFI Input Threshold
PFI Input Hysteresis
PFI Input Current
PFO
Output Low Voltage
PFO
Output High Voltage
(Push-Pull Output)
PFO
Leakage Current
(Open-Drain Output)
PFO
Delay Time
MANUAL RESET (MR)
Input Low Voltage
Input High Voltage
Pullup Resistance
Glitch Immunity
MR
to Reset Delay
V
IL
V
IH
Pullup resistance to V
CC
0.7 x V
CC
20
30
100
120
0.3 x V
CC
V
kΩ
ns
ns
V
PFT
V
PFI-HYS
I
PFI
V
OUT
= 1.8V, I
SINK
= 1mA,
PFO
asserted
V
OUT
=1.2V, I
SINK
= 100µA,
PFO
asserted
I
SOURCE
= 100µA,
PFO
deasserted
V
PFO
= 5.5V,
PFO
deasserted
(V
PFI
+ 100mV) to (V
PFI
- 100mV)
20
V
OUT
- 0.3V
1
-1
V
PFI
falling, 1.6V
≤
V
CC
≤
5.5V
0.570
0.590
30
+1
0.3
0.3
0.611
V
mV
µA
V
V
µA
µs
V
TH
t
RD
t
RP
V
OL
V
CC
falling at 10V/ms
V
CC
rising
V
OUT
= 3.3V, I
SINK
= 3.2mA,
RESET
asserted
V
OUT
= 1.8V, I
SINK
= 1mA,
RESET
asserted
V
OUT
= 1.2V, I
SINK
= 100µA,
RESET
asserted
V
OH
V
CC
≥
1.1 x V
TH
, I
SOURCE
= 100µA,
RESET
deasserted
V
RESET
= 5.5V, reset deasserted
V
OUT
- 0.3V
1
145
(See Table 1)
20
215
285
0.3
0.3
0.3
V
µA
V
V
µs
ms
V
CC
= 1.6V
V
CC
≥
2V
V
BATT
= 5.5V
MIN
TYP
0.2
0.15
500
200
180
150
150
75
150
10
mA
nA
mV
MAX
1.0
1.0
UNITS
%/V
%
MAX16023/MAX16024
_______________________________________________________________________________________
3
Battery-Backup Circuits with
Regulated Output Voltage
MAX16023/MAX16024
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 1.53V to 5.5V, V
BATT
= 3V, reset not asserted, T
A
= T
J
= -40°C to +85°C, C
OUT
= 10µF, unless otherwise noted. Typical val-
ues are at T
A
= T
J
= +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
V
OUT
= 1.2V, I
SINK
= 100µA, BATT ON
deasserted
Output Low Voltage
V
OL
V
OUT
= 1.8V, I
SINK
= 1mA, BATT ON
deasserted
V
OUT
= 3.3V, I
SINK
= 3.2mA, BATT ON
deasserted
Output High Voltage
(Push-Pull Output)
Output Leakage Current
(Open-Drain Output)
Output Short-Circuit Current
CE GATING (CEIN,
CEOUT)
CEIN
Leakage Current
CEIN
to
CEOUT
Resistance
CEOUT
Short-Circuit Current
CEIN
to
CEOUT
Propagation
Delay
Output High Voltage
Reset to
CEOUT
Delay
V
OH
Reset asserted, V
CC
= 0.9 x V
TH
or 0
V
CC
= 5V, reset deasserted
Reset asserted,
CEOUT
= 0
50Ω source, C
LOAD
= 50pF, V
CC
= 4.75V
I
SOURCE
= 100µA, reset asserted
V
OUT
- 0.3V
12
-1
8
0.75
1.5
+1
50
2
7
µA
Ω
mA
ns
V
µs
V
OH
I
SOURCE
= 100µA, BATT ON asserted
V
CC
= 5.5V
Sink current, V
CC
= 5V
(Note 6)
60
V
OUT
- 0.3V
1
MIN
TYP
MAX
UNITS
BATTERY-ON INDICATOR (BATT ON)
0.3
0.3
0.3
V
µA
mA
V
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
All devices are 100% production tested at T
A
= +25°C and T
A
= +85°C. Limits over temperature are guaranteed by design.
V
BATT
can be 0 anytime or V
CC
can go down to 0 if V
BATT
is active (except at startup).
Dropout voltage is defined as (V
IN
- V
OUT
) when V
OUT
is 2% below the value of V
OUT
when V
IN
= V
OUT
+ 1V.
CEIN
to
CEOUT
resistance is tested with V
CC
= 5V and V
CEIN
= 0 or 5V.
Use external current-limiting resistor to limit current to 20mA (max).
4
_______________________________________________________________________________________
Battery-Backup Circuits with
Regulated Output Voltage
MAX16023/MAX16024
Table 1. Reset Threshold Ranges
SUFFIX
L
M
T
S
R
Z
Y
W
V
RESET THRESHOLD RANGES (V)
MIN
4.508
4.264
2.991
2.845
2.549
2.243
2.117
1.603
1.514
TYP
4.63
4.38
3.08
2.93
2.63
2.32
2.19
1.67
1.575
MAX
4.906
4.635
3.239
3.080
2.755
2.425
2.288
1.733
1.639
Table 2. Fixed Output Voltage
SUFFIX
33
30
25
18
12
NOMINAL OUTPUT
VOLTAGE (V)
3.3
3.0
2.5
1.8
1.2
Typical Operating Characteristics
(V
CC
= 5V, V
BATT
= 0, I
OUT
= 0, T
A
= +25°C, unless otherwise noted.)
V
CC
SUPPLY CURRENT
vs. V
CC
SUPPLY VOLTAGE
MAX16023 toc01
V
CC
SUPPLY CURRENT
vs. TEMPERATURE
MAX16023 toc02
BATT SUPPLY CURRENT
vs. V
CC
SUPPLY VOLTAGE
MAX16024PTBS25+
V
OUT
= 2.5V
V
TH
= 2.93V
MAX16023 toc03
25
MAX16024PTBS25+
V
OUT
= 2.5V
V
TH
= 2.93V
10
9
V
CC
SUPPLY CURRENT (μA)
8
7
6
5
4
3
2
1
MAX16024PTBS25+
V
OUT
= 2.5V
V
TH
= 2.93V
6
5
4
3
V
BATT
= 3.0V
2
V
BATT
= 2.8V
1
0
15
10
5
0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V
CC
SUPPLY VOLTAGE (V)
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
BATT SUPPLY CURRENT (μA)
V
CC
SUPPLY CURRENT (μA)
20
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
V
CC
SUPPLY VOLTAGE (V)
BATTERY SUPPLY CURRENT
vs. TEMPERATURE
MAX16023 toc04
BATT STANDBY CURRENT
vs. TEMPERATURE
MAX16023 toc05
RESET OUTPUT VOLTAGE LOW
vs. SINK CURRENT
MAX16024PTBS25+
OUTPUT VOLTAGE LOW (V)
0.8
MAX16023 toc06
5
BATTERY SUPPLY CURRENT (μA)
MAX16024PTBS25+
V
BATT
= +3.0V
V
CC
= 0
10
8
BATT STANDBY CURRENT (nA)
6
4
2
0
-2
-4
-6
-8
V
CC
= 3.3V
V
BATT
= 3.0V
1.0
4
3
0.6
2
0.4
1
0.2
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
-10
-40
-15
10
35
60
85
TEMPERATURE (°C)
0
0
2
4
6
8
10 12
14 16
18 20
SINK CURRENT (mA)
_______________________________________________________________________________________
5
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