LTC3567 Datasheet, PDF (9/28 Pages) Linear Technology – High Effi ciency USB Power Manager Plus 1A Buck-Boost Converter with I2C Control

LTC3567
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise noted.
Buck-Boost Regulator PWM Mode
Efficiency
100
90
80
BURST MODE
OPERATION
70
CURVES
60
V_IN1 = 3V
V_IN1 = 3.6V
50
V_IN1 = 4.5V
40
PWM MODE
CURVES
V_IN1 = 3V
V_IN1 = 3.6V
V_IN1 = 4.5V
30
20
10
0
0.1
V_OUT1 = 3.3V
TYPE 3 COMPENSATION
1
10
100
1000
I_LOAD (mA)
3567 G25
Buck-Boost Regulator Load
Regulation
3.333
3.322
V_IN1 = 3V
V_IN1 = 3.6V
V_IN1 = 4.5V
3.311
3.300
3.289
3.278
V_OUT1 = 3.3V
TYPE 3 COMPENSATION
3.267
1
10
100
I_LOAD (mA)
1A
3567 G28
Buck-Boost Regulator PWM
Efficiency vs V_IN1
100
90
80
70
60
I_LOAD = 50mA
I_LOAD = 200mA
50
I_LOAD = 1000mA
40
30
20
10 VOUT1 = 3.3V
TYPE 3 COMPENSATION
0
2.7 3.1 3.5 3.9 4.3
V_IN1 (V)
4.7
3567 G26
Buck-Boost Regulator vs I_LOAD
100 _{BURST MODE OPERATION}
90 ^CURVES
80
70
60
50
40
V_IN1 = 3V
V_IN1 = 3.6V
30
V_IN1 = 4.5V
PWM MODE
CURVES
V_IN1 = 3V
V_IN1 = 3.6V
V_IN1 = 4.5V
20
10
0
0.1
V_OUT1 = 5V
TYPE 3 COMPENSATION
1
10
100
1000
I_LOAD (mA)
3567 G27
Reduction in Current
Deliverability at Low V_IN1
300
STEADY STATE I_LOAD
START-UP WITH A
250
RESISTIVE LOAD
START-UP WITH A
CURRENT SOURCE LOAD
200
Buck-Boost Regulator Load Step,
0mA to 300mA
CH1 V_OUT1
AC 100mV/DIV
150
100
CH2 I_LOAD
DC 200mA/DIV
50
V_OUT1 = 3.3V
TYPE 3 COMPENSATION
0
2.7 3.1 3.5 3.9 4.3 4.7
V_IN1 (V)
3567 G29
V_IN1 = 4.2V
V_OUT1 = 3.3V
L = 2.2μH
C_OUT = 47μF
100μs/DIV
3567 G30
PIN FUNCTIONS
LDO3V3 (Pin 1): 3.3V LDO Output Pin. This pin provides
a regulated always-on, 3.3V supply voltage. LDO3V3
gets its power from V_OUT. It may be used for light loads
such as a watchdog microprocessor or real time clock.
A 1μF capacitor is required from LDO3V3 to ground. If
the LDO3V3 output is not used it should be disabled by
connecting it to V_OUT.
CLPROG (Pin 2): USB Current Limit Program and Moni-
tor Pin. A resistor from CLPROG to ground determines
the upper limit of the current drawn from the V_BUS pin.
A fraction of the V_BUS current is sent to the CLPROG pin
when the synchronous switch of the PowerPath switching
regulator is on. The switching regulator delivers power
until the CLPROG pin reaches 1.188V. Several V_BUS cur-
rent limit settings are available via user input which will
typically correspond to the 500mA and the 100mA USB
specifications. A multilayer ceramic averaging capacitor
or R-C network is required at CLPROG for filtering.
NTC (Pin 3): Input to the Thermistor Monitoring Circuits.
The NTC pin connects to a battery’s thermistor to deter-
mine if the battery is too hot or too cold to charge. If the
battery’s temperature is out of range, charging is paused
3567f
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