LTC3868-1_15 Datasheet, PDF (3/38 Pages) Linear Technology – Low IQ, Dual 2-Phase Synchronous Step-Down Controller

LTC3868-1
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_RUN1,2 = 5V, EXTV_CC = 0V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
V_IN
V_FB1,2
I_FB1,2
V_REFLNREG
V_LOADREG
Input Supply Operating Voltage Range
Regulated Feedback Voltage
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
g_m1,2
I_Q
Transconductance Amplifier g_m
Input DC Supply Current
Pulse-Skipping or Forced Continuous
Mode (One Channel On)
Pulse-Skipping or Forced Continuous
Mode (Both Channels On)
(Note 4) I_TH1,2 Voltage = 1.2V
l
(Note 4)
(Note 4) V_IN = 4.5V to 24V
(Note4)
Measured in Servo Loop,
l
∆I_TH Voltage = 1.2V to 0.7V
(Note4)
Measured in Servo Loop,
l
∆I_TH Voltage = 1.2V to 2V
(Note 4) I_TH1,2 = 1.2V, Sink/Source = 5μA
(Note 5)
RUN1 = 5V and RUN2 = 0V, V_FB1 = 0.83V (No Load) or
RUN1 = 0V and RUN2 = 5V, V_FB2 = 0.83V (No Load)
RUN1,2 = 5V, V_FB1,2 = 0.83V (No Load)
4
0.788
0.8
±5
0.002
0.01
–0.01
2
1.3
2
24
V
0.812
V
±50
nA
0.02 %/V
0.1
%
–0.1
%
mmho
mA
mA
Sleep Mode (One Channel On)
Sleep Mode (Both Channels On)
Shutdown
RUN1 = 5V and RUN2 = 0V, V_FB1 = 0.83V (No Load) or
RUN1 = 0V and RUN2 = 5V, V_FB2 = 0.83V (No Load)
RUN1,2 = 5V, V_FB1,2 = 0.83V (No Load)
RUN1,2 = 0V
170
250
μA
300 450
μA
8
25
μA
UVLO
V_OVL
I_SENSE+
I_SENSE–
Undervoltage Lockout
Feedback Overvoltage Protection
SENSE⁺ Pin Current
SENSE^– Pin Current
DF_MAX
Maximum Duty Factor
I_SS1,2
Soft-Start Charge Current
V_RUN1,2 On RUN Pin On Threshold
V_RUN1,2 Hyst RUN Pin Hysteresis
V_SS1,2 LA SS Pin Latchoff Arming Threshold
V_SS1,2 LT SS Pin Latchoff Threshold
I_DSC1,2 LT SS Discharge Current
V_SENSE(MAX) Maximum Current Sense Threshold
Gate Driver
INTV_CC Ramping Up
INTV_CC Ramping Down
Measured at V_FB1,2, Relative to Regulated
V_FB1,2
Each Channel
Each Channel
V_OUT1,2 < INTV_CC – 0.5V
V_OUT1,2 > INTV_CC + 0.5V
In Dropout, FREQ = 0V
V_SS1,2 = 0V
V_RUN1, V_RUN2 Rising
V_SS1, V_SS2 Rising from 1V
V_SS1, V_SS2 Rising from 2V
Short-Circuit Condition V_FB1,2 = 0V
V_SS1,2 = 5V
V_FB1,2 = 0.7V, V_SENSE1–,₂– = 3.3V
l
4
4.2
V
l 3.6
3.8
4
V
7
10
13
%
±1
μA
±1
μA
550 950
μA
98
99.4
%
0.7
1
1.4
μA
l 1.21 1.26 1.31
V
50
mV
1.9
2
2.1
V
1.3
1.5
1.7
V
7
10
13
μA
43
50
57
mV
TG1,2
Pull-Up On-Resistance
Pull-Down On-Resistance
2.5
Ω
1.5
Ω
BG1,2
Pull-Up On-Resistance
Pull-Down On-Resistance
2.4
Ω
1.1
Ω
TG1,2 t_r
TG1,2 t_f
TG Transition Time:
Rise Time
Fall Time
(Note 6)
C_LOAD = 3300pF
C_LOAD = 3300pF
25
ns
16
ns
38681fd
3