LTC3728_15 Datasheet, PDF (3/36 Pages) Linear Technology – Dual, 550kHz, 2-Phase Synchronous Step-Down Switching Regulator

LTC3728
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 = 15V, V_{RUN/SS1, 2} = 5V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Main Control Loops
V_{OSENSE1, 2}
I_{OSENSE1, 2}
V_REFLNREG
V_LOADREG
g_{m1, 2}
g_{mGBW1, 2}
V_FCB
I_FCB
V_BINHIBIT
Regulated Feedback Voltage
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
Transconductance Amplifier g_m
Transconductance Amplifier GBW
Input DC Supply Current
Normal Mode
Shutdown
Forced Continuous Threshold
Forced Continuous Pin Current
Burst Inhibit (Constant-Frequency)
Threshold
(Note 3); I_{TH1, 2} Voltage = 1.2V
l
(Note 3)
V_IN = 3.6V to 30V (Note 3)
(Note 3)
Measured in Servo Loop; ΔI_TH Voltage = 1.2V to 0.7V l
Measured in Servo Loop; ΔI_TH Voltage = 1.2V to 2.0V l
I_{TH1, 2} = 1.2V; Sink/Source 5μA (Note 3)
I_{TH1, 2} = 1.2V (Note 3)
(Note 4)
V_IN = 15V; EXTV_CC Tied to V_OUT1; V_OUT1 = 5V
V_{RUN/SS1, 2} = 0V
l
V_FCB = 0.85V
Measured at FCB Pin
0.792
0.76
–0.50
0.800 0.808
V
–5 –50 nA
0.002 0.02 %/V
0.1 0.5
%
–0.1 –0.5 %
1.3
mmho
3
MHzI_Q
450
μA
20 35
μA
0.800 0.84
V
–0.18 –0.1 μA
4.3 4.8
V
UVLO
V_OVL
I_SENSE
DF_MAX
I_{RUN/SS1, 2}
V_{RUN/SS1, 2} ON
V_{RUN/SS1, 2} LT
Undervoltage Lockout
Feedback Overvoltage Lockout
Sense Pins Total Source Current
Maximum Duty Factor
Soft-Start Charge Current
RUN/SS Pin ON Threshold
RUN/SS Pin Latchoff Arming
Threshold
V_IN Ramping Down
Measured at V_{OSENSE1, 2}
(Each Channel); V_SENSE1–_{, 2}– = V_SENSE1+_{, 2}+ = 0V
In Dropout
V_{RUN/SS1, 2} = 1.9V
V_RUN/SS1, V_RUN/SS2 Rising
V_RUN/SS1, V_RUN/SS2 Rising from 3V
l
3.5 4
V
l 0.84 0.86 0.88
V
–85
–60
μA
98
99.4
%
0.5
1.2
μA
1.0
1.5 1.9
V
3.8 4.5
V
I_{SCL1, 2}
RUN/SS Discharge Current
I_SDLHO
V_SENSE(MAX)
Shutdown Latch Disable Current
Maximum Current Sense Threshold
TG1, 2 t_r
TG1, 2 t_f
BG1, 2 t_r
BG1, 2 t_f
TG/BG t_1D
TG Transition Time:
Rise Time
Fall Time
BG Transition Time:
Rise Time
Fall Time
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
BG/TG t_2D
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
t_ON(MIN)
Minimum On-Time
INTV_CC Linear Regulator
V_INTVCC
Internal V_CC Voltage
V_LDOINT
INTV_CC Load Regulation
V_LDOEXT
EXTV_CC Voltage Drop
Soft-Short Condition V_{OSENSE1, 2} = 0.5V;
V_{RUN/SS1, 2} = 4.5V
V_{OSENSE1, 2} = 0.5V
V_{OSENSE1, 2} = 0.7V, V_OSENSE1–_{, 2}– = 5V
V_{OSENSE1, 2} = 0.7V, V_OSENSE1–_{, 2}– = 5V
(Note 5)
C_LOAD = 3300pF
C_LOAD = 3300pF
(Note 5)
C_LOAD = 3300pF
C_LOAD = 3300pF
C_LOAD = 3300pF Each Driver
C_LOAD = 3300pF Each Driver
Tested with a Square Wave (Note 6)
6V < V_IN < 30V, V_EXTVCC = 4V
I_CC = 0 to 20mA, V_EXTVCC = 4V
I_CC = 20mA, V_EXTVCC = 5V
0.5
65
l 62
2
4
μA
1.6 5
μA
75 85 mV
75 88 mV
50 90
ns
50 90
ns
40 90
ns
40 80
ns
90
ns
90
ns
100
ns
48
5.0 5.2
V
0.2 1.0
%
80 160 mV
3728fg
3