LTC3728LCGN-PBF Datasheet, PDF (4/38 Pages) Linear Technology – Dual, 550kHz, 2-Phase Synchronous Regulators

LTC3728L/LTC3728LX
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} Regulated Feedback Voltage
(Note 3); I_{TH1, 2} Voltage = 1.2V (LTC3728LC)
(Note 3); I_{TH1, 2} Voltage = 1.2V
(LTC3728LE/LTC3728LX/LTC3728LI)
● 0.792 0.800 0.808
V
● 0.788 0.800 0.812
V
I_{VOSENSE1, 2}
V_REFLNREG
V_LOADREG
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
g_{m1, 2}
g_{mGBW1, 2}
I_Q
V_FCB
I_FCB
V_BINHIBIT
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)
– 5 –50
V_IN = 3.6V to 30V (Note 3)
0.002 0.02
(Note 3)
Measured in Servo Loop; ΔI_TH Voltage = 1.2V to 0.7V ●
Measured in Servo Loop; ΔI_TH Voltage = 1.2V to 2.0V ●
0.1 0.5
– 0.1 –0.5
I_{TH1, 2} = 1.2V; Sink/Source 5µA (Note 3)
1.3
I_{TH1, 2} = 1.2V (Note 8)
3
(Note 4)
V_IN = 15V; EXTV_CC Tied to V_OUT1; V_OUT1 = 5V
V_{RUN/SS1, 2} = 0V
450
20 35
● 0.76 0.800 0.84
V_FCB = 0.85V
Measured at FCB Pin
– 0.50 –0.18 –0.1
4.3 4.8
nA
%/V
%
%
mmho
MHz
µA
µA
V
µA
V
UVLO
Undervoltage Lockout
V_IN Ramping Down
●
3.5
4
V
V_OVL
Feedback Overvoltage Lockout
Measured at V_{OSENSE1, 2}
● 0.84 0.86 0.88
V
I_SENSE
Sense Pins Total Source Current
(Each Channel); V_SENSE1–_{, 2}– = V_SENSE1+_{, 2}+ = 0V
–90 –60
µA
DF_MAX
Maximum Duty Factor
In Dropout
98 99.4
%
I_{RUN/SS1, 2}
Soft-Start Charge Current
V_{RUN/SS1, 2} = 1.9V
0.5 1.2
µA
V_{RUN/SS1, 2} ON RUN/SS Pin ON Threshold
V_RUN/SS1, V_RUN/SS2 Rising
1.0 1.5 2.0
V
V_{RUN/SS1, 2} LT RUN/SS Pin Latchoff Arming
Threshold
V_RUN/SS1, V_RUN/SS2 Rising from 3V
4.1 4.75
V
I_{SCL1, 2}
I_SDLHO
V_SENSE(MAX)
TG1, 2 t_r
TG1, 2 t_f
BG1, 2 t_r
BG1, 2 t_f
TG/BG t_1D
BG/TG t_2D
t_ON(MIN)
RUN/SS Discharge Current
Shutdown Latch Disable Current
Maximum Current Sense Threshold
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
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
Minimum On-Time
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_SENSE1–_{, 2} – = 5V
V_{OSENSE1, 2} = 0.7V, V_SENSE1–_{, 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)
0.5 2
4
µA
1.6
5
µA
65 75 85
mV
● 62 75 88
mV
55 100
ns
55 100
ns
45 100
ns
45 90
ns
80
ns
80
ns
100
ns
3728lxff
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