Buck Converter. LTC3552-1 Datasheet

LTC3552-1 Converter. Datasheet pdf. Equivalent

Part LTC3552-1
Description Standalone Linear Li-Ion Battery Charger and Dual Synchronous Buck Converter
Feature www.DataSheet4U.com FEATURES ■ ■ ■ LTC3552-1 Standalone Linear Li-Ion Battery Charger and Dual Syn.
Manufacture Linear Technology
Datasheet
Download LTC3552-1 Datasheet




LTC3552-1
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LTC3552-1
FEATURES
Standalone Linear Li-Ion
Battery Charger and Dual
Synchronous Buck Converter
DESCRIPTIO
Programmable Charge Current Up to 950mA
Complete Linear Charger and Dual DC/DC
Regulator
Dual Fixed Outputs:
1.8V at 800mA
1.575V at 400mA
No MOSFET, Sense Resistor or Blocking Diode
Required
Thermal Regulation Maximizes Charge Rate
Without Risk of Overheating*
Charges Directly from a USB Port
Programmable Charge Current Termination
Preset 4.2V Charge Voltage with ±1% Accuracy
Charge Current Monitor Output for Gas Gauging*
Automatic Recharge
Charge Status Output
“Power Present” Output
Soft-Start Limits Inrush Current
Low Quiescent Current Buck Converter (40µA)
Current Mode Operation, Constant Frequency (2.25MHz)
Low Profile (5mm × 3mm × 0.75mm) DFN Package
U
APPLICATIO S
Cellular Telephones, PDAs, MP3 Players
Bluetooth Applications
The LTC®3552-1 is a complete constant-current/constant-
voltage linear charger and dual fixed output DC/DC con-
verter for single cell lithium-ion batteries. Its DFN package
and low external component count make the LTC3552-1
ideally suited for portable applications. Furthermore,
the LTC3552-1 is designed to work within USB power
specifications.
No external sense resistor or external blocking diode are
required due to the internal MOSFET architecture. The
charge voltage is fixed at 4.2V and the charge current is
programmed with a resistor. The charge cycle terminates
when the charge current drops below the programmed
termination threshold after the final float voltage is
reached. When the input supply (wall adapter or USB
supply) is removed, the LTC3552-1 enters a low current
state dropping the battery drain current to less than 2µA.
Thermal regulation maximizes charge rate without risk
of overheating.
The synchronous step-down switching regulators
generate fixed output voltages of 1.8V and 1.575V.
The switching frequency is set at 2.25MHz, allowing the
use of small surface mount inductors and capacitors.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by U.S. patents, including 6522118, 6700364, 5481178, 6580258, 6304066,
6127815, 6498466, 6611131.
TYPICAL APPLICATIO
Single Cell Li-Ion Battery Charger with
C/5 Termination and Dual DC/DC Converter
VIN
4.5V TO
6.5V
VOUT2
1.575V/
400mA
1µF
6191.24k
4.7µH
COUT2
10µF
CER
CFF2
330pF
VIN
ITERM
PROG
RUN1
RUN2
CHRG
BAT
PWR LTC3552-1 VCC
EN
SW2 SW1
VOUT2
VOUT1
VFB2 GND VFB1
800mA
+
10µF
2.2µH
CFF1
330pF
4.2V
1-CELL
Li-Ion
BATTERY
VOUT1
1.8V/
800mA
COUT1
10µF
CER
35521 TA01
Efficiency Curve/
Power Loss of Regulators
100
1000
95
90 VOUT1 = 1.8V
85
VOUT2 = 1.575V
100
80
CHANNEL 1
75
70 CHANNEL 2
10
1
65 VIN = 3.6V
Burst Mode OPERATION
60 0.1
1 10 100 1000
LOAD CURRENT (mA)
35521 TAO1b
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LTC3552-1
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LTC3552-1
ABSOLUTE AXI U RATI GS
(Note 1)
Input Supply Voltage (VIN) ......................... –0.3V to 10V
PROG, ITERM .................................. –0.3V to VIN + 0.3V
BAT .............................................................. –0.3V to 7V
CHRG, PWR, EN......................................... –0.3V to 10V
BAT Short-Circuit Duration............................Continuous
BAT Pin Current ..........................................................1A
PROG Pin Current ....................................................1mA
VCC Supply Voltage ...................................... –0.3V to 6V
VOUT1, VOUT2, RUN1,
RUN2 Voltages .............................–0.3V to VCC +0.3V
VFB1, VFB2 ........................................–0.3V to VCC + 0.3V
SW1, SW2 Voltage...........................–0.3V to VCC + 0.3V
Ambient Operating Temperature
Range (Note 2) .................................... –40°C to 85°C
Maximum Junction Temperature (Note 8) ............ 125°C
Storage Temperature Range................... –65°C to 125°C
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
ITERM 1
BAT 2
CHRG 3
RUN2 4
SW2 5
RUN1 6
VOUT2 7
VFB2 8
16 EN
15 PWR
14 VIN
13 PROG
17
12 SW1
11 VCC
10 VOUT1
9 VFB1
DHC PACKAGE
16-LEAD (5mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 40°C/W (Note 3)
EXPOSED PAD IS GROUND (PIN 17) MUST BE SOLDERED TO PCB
ORDER PART NUMBER DHC PART MARKING
LTC3552EDHC-1
35521
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 5V, VCC = 3.6V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Battery Charger
VIN
IIN
VFLOAT
IBAT
VUV
VUVHYS
VEN(IL)
VEN(IH)
REN
VASD
ITERM
Input Supply Voltage
4.25
8
Input Supply Current
Charge Mode (Note 4)
Standby Mode
Shutdown Mode
RPROG = 10k
Charge Terminated
EN = 5V, VIN < VBAT or VIN < VUV
0.4 1
200 500
25 50
Regulated Output (Float) Voltage
0°C ≤ TA ≤ 85°C, 4.3V < VIN < 8V
4.158 4.2 4.242
BAT Pin Current
RPROG = 10k, Current Mode
92 100 105
RPROG = 2k, Current Mode
465 500 535
Standby Mode, VBAT = 4.2V
–2.5 –6
Shutdown Mode (EN = 5V, VIN < VBAT or
±1 ±2
VIN < VUV)
Sleep Mode, VIN = 0V
±1 ±2
VIN Undervoltage Lockout Voltage
From VIN Low to High
3.7
3.8 3.92
VIN Undervoltage Lockout Hysteresis
EN Pin Input Low Voltage
150 200 300
0.4
0.7
EN Pin Input High Voltage
0.7 1
EN Pin Pull-Down Resistor
1.2
2
5
VIN – VBAT Lockout Threshold Voltage
Charge Termination Current Threshold
VIN from Low to High
VIN from High to Low
RTERM = 1k
RTERM = 5k
70 100 140
5 30 50
90 100 110
17.5 20 22.5
V
mA
µA
µA
µA
mA
mA
µA
µA
µA
V
mV
V
V
mΩ
mV
mV
mA
mA
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