LTC3827 Datasheet, PDF (3/36 Pages) Linear Technology – Low IQ, Dual, 2-Phase Synchronous Step-Down Controller

LTC3827
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 = 12V, V_{RUN/SS1, 2} = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX
Main Control Loops
V_{FB1, 2}
I_{VFB1, 2}
V_REFLNREG
V_LOADREG
g_{m1, 2}
I_Q
UVLO
V_OVL
I_SENSE
DF_MAX
I_{TRACK/SS1, 2}
V_{RUN1, 2} ON
V_SENSE(MAX)
TG1, 2 t_r
TG1, 2 t_f
BG1, 2 t_r
BG1, 2 t_f
TG/BG t_1D
Regulated Feedback Voltage
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
Transconductance Amplifier g_m
Input DC Supply Current
Sleep Mode (Channel 1 On)
Sleep Mode (Channel 2 On)
Shutdown
Sleep Mode (Both Channels)
Undervoltage Lockout
Feedback Overvoltage Lockout
Sense Pins Total Source Current
Maximum Duty Factor
Soft-Start Charge Current
RUN Pin ON Threshold
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
(Note 4) I_{TH1, 2} Voltage = 1.2V
(Note 4)
V_IN = 4V to 30V (Note 4)
(Note 4)
Measured in Servo Loop; ΔI_TH Voltage = 1.2V to 0.7V
Measured in Servo Loop; ΔI_TH Voltage = 1.2V to 2V
I_{TH1, 2} = 1.2V; Sink/Source 5μA (Note 4)
(Note 5)
RUN1 = 5V, RUN2 = 0V, V_FB1 = 0.83V (No Load)
RUN1 = 0V, RUN2 = 5V, V_FB2 = 0.83V (No Load)
V_{RUN1, 2} = 0V
RUN1,2 = 5V, V_FB1 = V_FB2 = 0.83V
V_IN Ramping Down
Measured at V_{FB1, 2}, Relative to Regulated V_{FB1, 2}
(Each Channel) V_SENSE1–_{, 2}– = V_SENSE1+_{, 2}+ = 0V
In Dropout
V_{TRACK1, 2} = 0V
V_RUN1, V_RUN2 Rising
V_{FB1, 2} = 0.7V,V_SENSE1–_{, 2}– = 3.3V
V_{FB1, 2} = 0.7V,V_SENSE1–_{, 2}– = 3.3V
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
C_LOAD = 3300pF Each Driver
● 0.792
0.800
–5
0.002
0.808
–50
0.02
●
0.1 0.5
●
– 0.1 –0.5
1.55
80 125
80 125
8
20
115 160
●
3.5
4
8
10
12
–660
98 99.4
0.75 1.0 1.35
0.5 0.7 0.9
90 100 110
● 80 100 115
50
90
50
90
40
90
40
80
70
BG/TG t_2D Bottom Gate Off to Top Gate On Delay C_LOAD = 3300pF Each Driver
70
Top Switch-On Delay Time
t_ON(MIN)
Minimum On-Time
INTV_CC Linear Regulator
V_INTVCCVIN Internal V_CC Voltage
V_LDOVIN
INTV_CC Load Regulation
V_INTVCCEXT Internal V_CC Voltage
V_LDOEXT
INTV_CC Load Regulation
V_EXTVCC
EXTV_CC Switchover Voltage
V_LDOHYS
EXTV_CC Hysteresis
Oscillator and Phase-Locked Loop
(Note 7)
8.5V < V_IN < 30V, V_EXTVCC = 0V
I_CC = 0mA to 20mA, V_EXTVCC = 0V
V_EXTVCC = 8.5V
I_CC = 0mA to 20mA, V_EXTVCC = 8.5V
EXTV_CC Ramping Positive
180
5.0 5.25 5.5
0.2 1.0
7.2 7.5 7.8
0.2 1.0
4.5 4.7
0.2
f_NOM
f_LOW
f_HIGH
f_SYNCMIN
Nominal Frequency
Lowest Frequency
Highest Frequency
Minimum Synchronizable Frequency
V_PLLLPF = Floating; PLLIN/MODE = DC Voltage
V_PLLLPF = 0V; PLLIN/MODE = DC Voltage
V_PLLLPF = INTV_CC; PLLIN/MODE = DC Voltage
PLLIN/MODE = External Clock; V_PLLLPF = 0V
360 400 440
220 250 280
475 530 580
115 140
UNITS
V
nA
%/V
%
%
mmho
μA
μA
μA
μA
V
%
μA
%
μA
V
mV
mV
ns
ns
ns
ns
ns
ns
ns
V
%
V
%
V
V
kHz
kHz
kHz
kHz
3827ff
3