LTC3727LX-1_15 Datasheet, PDF (3/28 Pages) Linear Technology – High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator

LTC3727LX-1
ELECTRICAL CHARACTERISTICS The ● 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
V_LOADREG
PARAMETER
Output Voltage Load Regulation
g_{m1, 2}
g_{mGBW1, 2}
I_Q
Transconductance Amplifier g_m
Transconductance Amplifier GBW
Input DC Supply Current
Normal Mode
Shutdown
V_FCB
I_FCB
V_BINHIBIT
Forced Continuous Threshold
Forced Continuous Pin Current
Burst Inhibit (Constant-Frequency)
Threshold
UVLO
Undervoltage Lockout
V_OVL
Feedback Overvoltage Lockout
I_SENSE
Sense Pins Total Source Current
DF_MAX
Maximum Duty Factor
I_{RUN/SS1, 2}
Soft-Start Charge Current
V_{RUN/SS1, 2} ON RUN/SS Pin ON Threshold
V_SENSE(MAX) Maximum Current Sense Threshold
TG1, 2 t_r
TG1, 2 t_f
TG Transition Time:
Rise Time
Fall Time
BG1, 2 t_r
BG1, 2 t_f
BG Transition Time:
Rise Time
Fall Time
TG/BG t_1D
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_LDO INT
INTV_CC Load Regulation
V_LDO EXT
EXTV_CC Voltage Drop
V_EXTVCC
EXTV_CC Switchover Voltage
V_LDOHYS
EXTV_CC Hysteresis
Oscillator and Phase-Locked Loop
f_NOM
f_LOW
f_HIGH
R_PLLIN
I_PLLFLTR
Nominal Frequency
Lowest Frequency
Highest Frequency
PLLIN Input Resistance
Phase Detector Output Current
Sinking Capability
Sourcing Capability
CONDITIONS
(Note 4)
Measured in Servo Loop; ∆I_TH Voltage = 1.2V to 0.7V ●
Measured in Servo Loop; ∆I_TH Voltage = 1.2V to 2.0V ●
I_{TH1, 2} = 1.2V; Sink/Source 5µA (Note 4)
I_{TH1, 2} = 1.2V (Note 4)
(Note 5)
V_IN = 15V, EXTV_CC Tied to V_OUT1, V_OUT1 = 8.5V
V_{RUN/SS1, 2} = 0V
●
V_FCB = 0.85V
Measured at FCB pin
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_{OSENSE1, 2} = 0.7V,V_SENSE1–_{, 2}– = 12V
●
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
C_LOAD = 3300pF Each Driver
C_LOAD = 3300pF Each Driver
8.5V < V_IN < 30V, V_EXTVCC = 6V
I_CC = 0mA to 20mA, V_EXTVCC = 6V
I_CC = 20mA, V_EXTVCC = 8.5V
I_CC = 20mA, EXTV_CC Ramping Positive
●
V_PLLFLTR = 1.2V
V_PLLFLTR = 0V
V_PLLFLTR ≥ 2.4V
f_PLLIN < f_OSC
f_PLLIN > f_OSC
MIN
0.76
– 0.30
0.84
– 85
98
0.5
1.0
105
7.2
6.9
350
220
460
TYP
0.1
– 0.1
1.3
3
1
20
0.800
– 0.18
6.8
3.5
0.86
– 60
99.4
1.2
1.5
135
50
50
40
40
90
90
120
7.5
0.2
70
7.3
0.3
380
255
530
100
–15
15
MAX UNITS
0.5
%
– 0.5
%
mmho
MHz
mA
35
µA
0.84
V
– 0.05
µA
7.3
V
4
V
0.88
V
µA
%
µA
1.9
V
165
mV
90
ns
90
ns
90
ns
80
ns
ns
ns
ns
7.8
V
1.0
%
160
mV
V
V
430
kHz
290
kHz
580
kHz
kΩ
µA
µA
3727lx1fa
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