LTC3335_15 Datasheet, PDF (1/28 Pages) Linear Technology – Nanopower Buck-Boost DC/DC with Integrated Coulomb Counter

Features
n _{680nA Input Quiescent Current (Output in}
Regulation at No Load)
n _{1.8V to 5.5V Input Operating Range}
n _{Selectable Output Voltages of 1.8V, 2.5V, 2.8V,}
3V, 3.3V, 3.6V, 4.5V, 5V
n _{Integrated Coulomb Counter Measures}
Accumulated Battery Discharge
n _{±5% Battery Discharge Measurement Accuracy}
n _{Programmable Peak Input Current of 5mA, 10mA,}
15mA, 25mA, 50mA, 100mA, 150mA, 250mA
n _{Up to 50mA of Output Current}
n _{Up to 90% Efficiency}
n _{Programmable Coulomb Counter Prescaler for Wide}
Range of Battery Sizes
n _{Programmable Discharge Alarm Threshold}
n _I²_{C Interface}
n _{Low Profile (0.75mm) 20-Lead (3mm × 4mm) QFN}
Package
Applications
n _{Long Lifetime Primary Cell Battery Applications}
n _{Wireless Sensors}
n _{Remote Monitors}
n _{Dust Networks}^® _SmartMesh^® _Applications
Electrical Specifications Subject to Change
LTC3335
Nanopower Buck-Boost
DC/DC with Integrated
Coulomb Counter
Description
The LTC^®3335 is a high efficiency, low quiescent current
(680nA) buck-boost DC/DC converter with an integrated
precision coulomb counter which monitors accumulated
battery discharge in long life battery powered applications.
The buck-boost can operate down to 1.8V on its input and
provides eight pin selectable output voltages with up to
50mA of output current.
The coulomb counter stores the accumulated battery dis-
charge in an internal register accessible via an I²C interface.
The LTC3335 features a programmable discharge alarm
threshold. When the threshold is reached, an interrupt is
generated at the IRQ pin.
To accommodate a wide range of battery types and sizes,
the peak input current can be selected from as low as 5mA
to as high as 250mA and the full-scale coulomb counter
has a programmable range of 32,768:1.
The LTC3335 is available in a 3mm × 4mm QFN-20 package.
L, LT, LTC, LTM, Linear Technology, the Linear logo, SmartMesh and Dust Networks are
registered trademarks of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
Typical Application
2.2mH TO 47µH
PRIMARY CELL ⁺
1.8V TO 5.5V
I_PEAK = 5mA TO 250mA _SW1
SW2
10µF
BAT
PBAT
EN
V_OUT
PV_OUT
DV_CC
10k
10k
LTC3335
I²C
SCL
SDA
3
IRQ
IPK[2:0]
PGOOD
3
OUT[2:0]
GND
3335 TA01
1.8V TO 5V
47µF
Efficiency vs Load for 100mA
I_PEAK Setting
100
90
80
70
60
50
40
30
20 _{BAT = 3.6V}
10
L = 150µH
DCR = 0.3Ω
0
0.001 0.01
0.1
1
I_LOAD (mA)
V_OUT = 1.8V
V_OUT = 2.5V
V_OUT = 3.3V
V_OUT = 5V
10
100
3335 TA01a
3335p
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1