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PDF MAX16023 Data sheet ( Hoja de datos )
| Número de pieza | MAX16023 | |
| Descripción | (MAX16023 / MAX16024) Battery-Backup Circuits | |
| Fabricantes | Maxim Integrated Products | |
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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
www.DataSheert4eUd.ucocme 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 VCC 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.
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.
Features
o System Monitoring for 5V, 3.3V, 3V, 2.5V, or 1.8V
Power-Supply Voltages
o 100mA Low-Dropout Regulator
o Factory-Trimmed and Adjustable Output Voltages
o 1.53V to 5.5V Operating Voltage Range
o Low-Power Consumption: 4µA (typ)
o Power-Fail Comparators for Monitoring Voltages
Down to 0.6V
o Battery-On Indicator
o Battery Freshness Seal
o On-Board Gating of CE Signals, 1.5ns
Propagation Delay (MAX16024)
o Debounced Manual-Reset Input
o 145ms (min) Reset Timeout Period
o Tiny 8-Pin and 10-Pin TDFN Packages
o UL® Certified to Conform to IEC60950-1
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX16023_TA_ _ _+T -40°C to +85°C 8 TDFN-EP*
MAX16024_TB_ _ _+T -40°C to +85°C 10 TDFN-EP*
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
8765
10 9 8 7 6
MAX16023
+ *EP
1234
MAX16024
+ *EP
12345
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.
1 page  
Battery-Backup Circuits with
Regulated Output Voltage
Table 1. Reset Threshold Ranges
SUFFIX
L
M
T
www.DataSheet4U.comS
R
Z
Y
W
V
RESET THRESHOLD RANGES (V)
MIN TYP MAX
4.508 4.63 4.906
4.264 4.38 4.635
2.991 3.08 3.239
2.845 2.93 3.080
2.549 2.63 2.755
2.243 2.32 2.425
2.117 2.19 2.288
1.603 1.67 1.733
1.514
1.575
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
(VCC = 5V, VBATT = 0, IOUT = 0, TA = +25°C, unless otherwise noted.)
VCC SUPPLY CURRENT
vs. VCC SUPPLY VOLTAGE
25
MAX16024PTBS25+
VOUT = 2.5V
20 VTH = 2.93V
15
10
5
0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
VCC SUPPLY VOLTAGE (V)
BATTERY SUPPLY CURRENT
vs. TEMPERATURE
5
MAX16024PTBS25+
VBATT = +3.0V
4 VCC = 0
3
2
1
0
-40
-15 10 35 60
TEMPERATURE (°C)
85
10
9
8
7
6
5
4
3
2
1
0
-40
10
8
6
4
2
0
-2
-4
-6
-8
-10
-40
VCC SUPPLY CURRENT
vs. TEMPERATURE
MAX16024PTBS25+
VOUT = 2.5V
VTH = 2.93V
-15 10 35 60
TEMPERATURE (°C)
85
BATT STANDBY CURRENT
vs. TEMPERATURE
VCC = 3.3V
VBATT = 3.0V
-15 10 35 60
TEMPERATURE (°C)
85
BATT SUPPLY CURRENT
vs. VCC SUPPLY VOLTAGE
6
MAX16024PTBS25+
5
VOUT = 2.5V
VTH = 2.93V
4
3
VBATT = 3.0V
2
VBATT = 2.8V
1
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
VCC SUPPLY VOLTAGE (V)
RESET OUTPUT VOLTAGE LOW
vs. SINK CURRENT
1.0
MAX16024PTBS25+
0.8
0.6
0.4
0.2
0
0 2 4 6 8 10 12 14 16 18 20
SINK CURRENT (mA)
_______________________________________________________________________________________ 5
5 Page 
Battery-Backup Circuits with
Regulated Output Voltage
Detailed Description
The Typical Applications Circuit shows a typical con-
nection using the MAX16024. OUT powers the SRAM. If
VCC is higher than the reset threshold (VTH), or if VCC is
lower than VTH but higher than VBATT, the regulator is
powered from VCC. If VCC < VTH, VCC < VBATT, and the
regulator is in dropout, the regulator is powered from
BATT (see the Functional Diagrams). OUT supplies up
www.DataSheett4oU1.c0o0mmA from VCC.
Backup-Battery Switchover
In a brownout or power failure, it may be necessary to
preserve the contents of the RAM. With a backup-bat-
tery installed at BATT, the MAX16023/MAX16024 auto-
matically switch the RAM to backup power when VCC
falls. The MAX16024 has a BATT ON output that goes
high when in battery-backup mode. Three conditions
must be met for these devices to switch to battery
backup mode:
1) VCC is lower than the reset threshold.
2) VCC is lower than VBATT.
3) The regulator is in dropout (except for the 1.2V out-
put version).
Chip-Enable Signal Gating (MAX16024)
The MAX16024 provides internal gating of CE signals to
prevent erroneous data from being written to CMOS
RAM in the event of a power failure or brownout. During
normal operation, the CE gate enables and passes all
CE transitions. When the reset output asserts, this path
becomes disabled, preventing erroneous data from cor-
rupting the CMOS RAM and CEOUT is pulled up to OUT
through an internal current source. The 1.5ns propaga-
tion delay from CEIN to CEOUT allows the devices to
be used with most µPs and high-speed DSPs.
During normal operation (reset not asserted), CEIN is
connected to CEOUT through a low on-resistance
transmission gate. If CEIN is high when a reset asserts,
CEOUT remains high regardless of any subsequent
transition on CEIN during the reset event.
If CEIN is low when reset asserts, CEOUT is held low for
12µs to allow completion of the read/write operation.
After the 12µs delay expires, CEOUT goes high and
stays high regardless of any subsequent transitions on
CEIN during the reset event. When CEOUT is discon-
nected from CEIN, CEOUT is actively pulled up to OUT.
The propagation delay through the chip-enable circuitry
depends on both the source impedance of the drive to
CEIN and the capacitive loading at CEOUT. Minimize
the capacitive load at CEOUT to minimize propagation
delay, and use a low-output-impedance driver.
VCC
RESET THRESHOLD VTH
CEIN
CEOUT
RESET-TO-CEOUT DELAY (12μs)
tRD
RESET
tRD
tRP
*
tRP
Figure 1. Reset and Chip-Enable Timing
* IF CEIN GOES HIGH BEFORE RESET ASSERTS,
CEOUT GOES HIGH WITHOUT DELAY AS
CEIN GOES HIGH.
______________________________________________________________________________________ 11
11 Page | ||
| Páginas | Total 17 Páginas | |
| PDF Descargar | [ Datasheet MAX16023.PDF ] | |
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