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LTC1559CS-5#TRPBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
1
LTC1559-3.3/LTC1559-5
Backup Battery Controller
with Fixed Output
■
Complete Battery Backup System in an SO-8,
16-Pin GN or SO Package
■
Generates Fixed Backup Voltage (3.07V/4.63V) from
a Single 1.2V NiCd Button Cell
■
Automatic Main Supply to Backup Switching
■
Minimum 100mW Output Power
■
Automatic Fast Recharge of NiCd Battery
■
Programmable NiCd Trickle Charge Current
■
Smart NiCd Charger Minimizes Recharge Time and
Maximizes System Efficiency After Backup
■
Onboard Power-Up and Push-Button Reset
Generator
■
Performs V
CC
Supervisory Functions
■
Reset Assertion Guaranteed at V
CC
= 1V
■
Short-Circuit Protection
■
Thermal Limiting
FEATURES
DESCRIPTION
U
The LTC
®
1559 is a backup battery controller that provides
all the functions necessary to implement a backup 3.3V or
5V power supply using a single NiCd cell. It includes a 1.2V
to 3.07V/4.63V boost converter, an intelligent 2-stage
battery charger, automatic backup switching and a micro-
processor reset generator. The boost converter uses a
synchronous switching architecture to achieve a typical
efficiency of 70%, ensuring maximum backup lifetime
from a small NiCd cell.
The on-chip NiCd charger uses an internal gas gauge to
minimize fast recharge time and prevent overcharging of
the backup cell, thereby improving system efficiency and
extending the life of the backup cell. The LTC1559 also
provides a user programmable trickle charge current to
compensate for self-discharge losses in the backup cell.
The LTC1559’s automatic backup switching scheme
requires minimum intervention from the host system and
provides feedback to the host to minimize system loading
in the backup state. Its internal V
CC
fault detector and reset
generator eliminate the need for a separate microproces-
sor supervisory chip in most applications.
The LTC1559 is available in an SO-8, 16-pin GN or SO
package.
APPLICATIONS
U
■
Notebook Computers
■
Palmtop Computers/PDAs
■
Portable Instruments
■
Battery-Powered Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
U
CTL
C1
1µF
**BACKUP
BATTERY
1.2V
NiCd
MAIN
BATTERY
4.5V TO 28V
R1
68k
SW
LTC1559-3.3
*L1
22µH
GND
PS
7
1
8
5
6
3
S1
RESET
1559 TA01
2
4
V
BAK
V
CC
RESET
BACKUP
+
C3
100µF
10V
V
OUT
3.3V AT NORMAL MODE
3A
V
BAK
33mA (3.07V) AT BACKUP MODE
>33mA (3.3V) AT NORMAL MODE
C2
1µF
SYSTEM
µP
R2
100k
Q1
P-MOSFET
Si9424DY
* SUMIDA CD54-22µH
** PANASONIC P-11AAH
† CONSULT LTC1435 DATA SHEET FOR
APPLICATION CIRCUIT INFORMATION
†
LTC1435
SYNCHRONOUS
BUCK
REGULATOR
+
+
Backup Time vs
V
BAK
Output Load Current
V
BAK
LOAD CURRENT (mA)
0
BACKUP TIME (MINUTES)
800
700
600
500
400
300
200
100
0
15 25
1559 TA02
510
20 30 35
V
BAK
= 3.07V
NiCd CELL = P-11AAH
(110mA Hrs)
2
LTC1559-3.3/LTC1559-5
ABSOLUTE MAXIMUM RATINGS
W
WW
U
(Note 1)
Terminal Voltages
V
CC
........................................................................ 6V
V
BAK
.................................................................... 12V
SW ...................................................................... 14V
All Other Pins .............................. –0.3V to V
CC
+ 0.3V
SW Input Currents ............................................. 500mA
V
BAK
Output Current................... Short-Circuit Protected
Operating Ambient Temperature Range ....... 0°C to 70°C
Junction Temperature .......................................... 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
ORDER PART
NUMBER
ORDER PART
NUMBER
S8 PART MARKING
LTC1559CS8-3.3
LTC1559CS8-5
ELECTRICAL CHARACTERISTICS
V
BAT
= 1.2V, T
A
= 0°C to 70°C unless otherwise noted.
LTC1559CGN-3.3
LTC1559CGN-5
LTC1559CS-3.3
LTC1559CS-5
Consult factory for Industrial and Military grade parts.
T
JMAX
= 125°C, θ
JA
= 130°C/ W
1
2
3
4
8
7
6
5
TOP VIEW
S8 PACKAGE
8-LEAD PLASTIC SO
SW
GND
CTL
PS
V
BAK
V
CC
BACKUP
RESET
T
JMAX
= 125°C, θ
JA
= 110°C/W (GN)
T
JMAX
= 125°C, θ
JA
= 110°C/W (S)
TOP VIEW
S PACKAGE
16-LEAD PLASTIC SO
GN PACKAGE
16-LEAD PLASTIC SSOP
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
SW
SW
PGND
GND
CTL
SHDN
PS
NC
V
BAK
V
BAK
V
CC
BACKUP
RESET
RESET
NC
LOBAT
PACKAGE/ORDER INFORMATION
W
U
U
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Battery Backup Switching
V
CC
Operating Voltage Range LTC1559-3.3 ● 2.900 3.5 V
LTC1559-5
● 4.400 5.5 V
V
BAT
Backup Battery Cell Voltage ● 1.0 1.2 1.5 V
I
VCC
Quiescent Supply Current (Note 2) ● 155 250 µA
I
BAT
Peak Inductor Current (Backup) Boost Converter in Low Current Mode (Note 7) ● 80 165 225 mA
Boost Converter in High Current Mode (Note 7)
● 225 330 445 mA
I
BAT(SHDN)
Battery Standby Current V
CC
= 0V ● 0.1 15 µA
I
VCC(SHDN)
Supply Current During Shutdown (Note 3) ● 50 µA
V
BAK(ON)
V
CC
Backup Request/Booster Assertion LTC1559-3.3 ● 3.011 3.070 3.127 V
Trip Point (Note 4) LTC1559-5
● 4.475 4.625 4.775 V
V
BAK(OFF)
V
CC
Backup Deassertion Trip Point LTC1559-3.3 ● 3.061 3.119 3.176 V
(Note 4) LTC1559-5
● 4.550 4.700 4.850 V
V
LOBAT1
Low V
BAT
Detect (Note 3) ● 0.95 1.00 1.05 V
V
UVLO(ON)
V
CC
UVLO Trip Voltage (Note 4) LTC1559-3.3 ● 2.904 3.003 3.102 V
LTC1559-5 ● 4.400 4.550 4.700 V
V
UVLO(OFF)
V
CC
UVLO Trip Voltage (Note 4) LTC1559-3.3 ● 3.061 3.119 3.176 V
LTC1559-5 ● 4.550 4.700 4.850 V
155933
15595
3
LTC1559-3.3/LTC1559-5
ELECTRICAL CHARACTERISTICS
V
BAT
= 1.2V, T
A
= 0°C to 70°C unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
UVLO Reset Monitor
V
LOBAT2
V
BAT
UVLO Trip Voltage (Note 5) ● 0.85 0.9 0.95 V
Backup Battery Charger
I
CHGF
Battery Charge Current During Fast Recharge ● 11 16 21 mA
I
CHGT
User-Programmable Trickle Charge ● 0.05 2 mA
Current Range
Q
RECH
Fast Recharge Factor (Note 6) 1.35 1.6 1.85 C/C
Q
TRK
Nominal Trickle Charge Multiplier Factor I
CHGT
= 1mA ● 8 10 12 A/A
V
CTL(CLAMP)
CTL Clamp Voltage in Trickle Mode I
CHGT
= 1mA ● 0.45 0.5 0.55 V
Push-Button Reset
V
CTL
CTL Input Threshold 250 mV
t
CTL
CTL Input Low Time (Debounce Time) 20 26 ms
Reset Timer
t
HRESET
Push-Button Duration for Hard Reset 1.10 1.8 3.4 sec
t
RST
RESET Pulse Width V
CTL
Low for <t
HRESET
(Soft Reset) ● 50 80 150 µs
V
CTL
Low for >t
HRESET
(Hard Reset) ● 115 185 345 ms
V
RST1
RESET Output Voltage V
CC
= 1V, I
SINK
= 10µA ● 5 200 mV
V
RST
RESET Output Voltage V
CC
= 4.25V, I
SINK
= 1.6mA ● 0.1 0.4 V
I
SC
RESET Output Current Output Source Current V
CC
= 3.3V 10 mA
Output Source Current V
CC
= 5V 20 mA
Short-Circuit Current Output Sink Current V
CC
= 3.3V 20 mA
Output Sink Current V
CC
= 5V 40 mA
PS Comparator
V
HYST
Comparator Threshold Hysteresis T
A
= 25°C90mV
Internal V
CC
Monitor Comparator
tr UVLO, Comparator Propagation Delay (Rising) 7.5 µs
Shutdown Pin (Note 3)
V
SHDN
SHDN Input Threshold Logic Low, V
IL
● 0.8 V
Logic High, V
IH
● 2V
I
SHDN
SHDN Pin Bias Current V
CC
= 5V, V
SHDN
= 0V ● 815 µA
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.
Note 2: Quiescent current is measured during push-button reset.
Note 3: Only applies to 16-pin version.
Note 4: Although the V
BAK(ON)
, V
BAK(OFF)
, V
UVLO(ON)
and V
UVLO(OFF)
threshold voltages have a specification tolerance, they are guaranteed by
design and tested in production never to overlap.
Note 5: Low cell voltage reset is only triggered when 0.25V < V
CTL
< 0.9V
for at least 20µs while in backup mode.
Note 6: Fast recharge factor is defined as the ratio of charge replenished to
the NiCd battery during fast recharge to the charge withdrawn from the
NiCd battery during backup.
Note 7: The LTC1559 switches automatically between the low and high
operating current levels. See Applications Information for more details.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20

LTC1559CS-5#TRPBF

Mfr. #:
Buy LTC1559CS-5#TRPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Battery Management 5V Backup Bat Ctl for DC/DC output
Lifecycle:
New from this manufacturer.
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