LTC3670_15 Datasheet, PDF (3/12 Pages) Linear Technology – Monolithic 400mA Buck Regulator with Dual 150mA

LTC3670
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T_A = 25°C. V_IN = 3.6V, unless otherwise noted.
SYMBOL PARAMETER
Synchronous Buck Regulator
CONDITIONS
MIN TYP MAX UNITS
f_OSC
Oscillator Frequency
V_BUCKFB
Buck Regulated Feedback Voltage
I_BUCKFB
Feedback Pin Input Bias Current
I_MAXP
PMOS Switch Maximum Peak Current (Note 6)
R_P(BUCK)
PMOS Switch On-Resistance
R_N(BUCK)
NMOS Switch On-Resistance
R_PD(BUCK) SW Pin Pull-Down Resistance in Shutdown
t_SS(BUCK)
Soft-Start Time
Each LDO Regulator
V_LDO
I_{LDO_FB}
LDO Regulated Feedback Voltage
LDO Line Regulation (Note 7)
LDO Load Regulation (Note 7)
Feedback Pin Input Bias Current
Short-Circuit Output Current (Note 6)
LDO Output, I_LDO = 1mA to 150mA
I_LDO = 1mA, V_IN = 2.5V to 5.5V
I_LDO = 1mA to 150mA
1.91 2.25 2.59
MHz
l 0.78
0.8
0.82
V
l
±20
nA
600
800 1100
mA
0.6
Ω
0.7
Ω
10
kΩ
0.6
ms
l 0.78
0.8
0.82
V
0.25
mV/V
–5
μV/mA
l
±20
nA
420
mA
V_DROP
t_SS(LDO)
R_PD(LDO)
Dropout Voltage (Note 8)
Soft-Start Time
Output Pull-Down Resistance in Shutdown
I_LDO = 150mA
V_IN = 3.6V
V_IN = 2.5V
150
200
mV
200
300
mV
0.1
ms
10
kΩ
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperatures will exceed 125°C when overtemperature protection is
active. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
Note 3: The LTC3670 is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 4: Dynamic supply current is higher due to the gate charge delivered
to the buck regulator’s internal MOSFET switches at the switching
frequency.
Note 5: PGOOD threshold is expressed as a percentage of the feedback
regulation voltage. The threshold is measured for the feedback pin voltage
rising.
Note 6: The current limit features are intended to protect the IC from
short term or intermittent fault conditions. Prolonged operation above
the specified Absolute Maximum pin current rating may result in device
degradation or failure.
Note 7: Measured with the LDO running unity gain, with output tied to
feedback pin.
Note 8: Dropout voltage is the minimum input to output voltage differential
needed for an LDO to maintain regulation at a specified output current.
When an LDO is in dropout, its output voltage will be equal to:
V_IN – V_DROP
3670f
3