LTC3548 Datasheet, PDF (3/16 Pages) Linear Technology – Dual Synchronous, 400mA/800mA, 2.25MHz Step-Down DC/DC Regulator

LTC3548
ELECTRICAL CHARACTERISTICS The ● 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 specified. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
POR
Power-On Reset Threshold
V_FB Ramping Down, MODE/SYNC = 0V
Power-On Reset On-Resistance
Power-On Reset Delay
–8.5
100
200
262,144
%
Ω
Cycles
V_RUN
I_RUN
RUN Threshold
RUN Leakage Current
● 0.3
1
1.5
V
●
0.01
1
µA
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired. No pin shall exceed 6V.
Note 2: The LTC3548 is guaranteed to meet specified performance from
0°C to 70°C. Specifications over the – 40°C and 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: The LTC3548 is tested in a proprietary test mode that connects
V_FB to the output of the error amplifier.
Note 4: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 5: T_J is calculated from the ambient T_A and power dissipation P_D
according to the following formula: T_J = T_A + (P_D • θ_JA).
Note 6: The DFN switch on-resistance is guaranteed by correlation to
wafer level measurements.
TYPICAL PERFOR A CE CHARACTERISTICS T_A = 25°C unless otherwise specified.
Burst Mode Operation
Pulse Skipping Mode
Load Step
SW
5V/DIV
V_OUT
20mV/DIV
I_L
200mA/DIV
V_IN = 3.6V
2µs/DIV
V_OUT = 1.8V
I_LOAD = 180mA
CHANNEL 1; CIRCUIT OF FIGURE 3
SW
5V/DIV
V_OUT
10mV/DIV
I_L
200mA/DIV
3548 G01
V_IN = 3.6V
1µs/DIV
V_OUT = 1.8V
I_LOAD = 30mA
CHANNEL 1; CIRCUIT OF FIGURE 3
V_OUT
200mV/DIV
I_L
500mA/DIV
I_LOAD
500mA/DIV
3548 G02
V_IN = 3.6V
20µs/DIV
V_OUT = 1.8V
I_LOAD = 80mA TO 800mA
CHANNEL 1; CIRCUIT OF FIGURE 3
3548 G03
Efficiency vs Input Voltage
100
95
90
85 _1mA
100mA
10mA
80 _800mA
75
70
65
V_OUT = 1.8V, CHANNEL 1
Burst Mode OPERATION
CIRCUIT OF FIGURE 3
60
2
3
4
5
INPUT VOLTAGE (V)
6
3548 G04
Oscillator Frequency vs
Temperature
2.5
V_IN = 3.6V
2.4
2.3
2.2
2.1
2.0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3548 G05
Oscillator Frequency vs Supply
Voltage
10
8
6
4
2
0
–2
–4
–6
–8
–10
2
3
4
5
6
SUPPLY VOLTAGE (V)
3548 G06
3548f
3