LTC3859_15 Datasheet, PDF (4/42 Pages) Linear Technology – Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller

LTC3859
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating junction
temperature range, otherwise specifications are at T_A = 25°C. V_BIAS = 12V, V_RUN1,2,3 = 5V, EXTV_CC = 0V unless otherwise noted. (Note 2)
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
UVLO
V_OVL1,2
I_SENSE1,2+
I_SENSE3+
I_SENSE1,2–
Undervoltage Lockout
Buck Feedback Overvoltage Protection
SENSE⁺ Pin Current
SENSE⁺ Pin Current
SENSE^– Pin Current
I_SENSE3–
SENSE^– Pin Current
DF_MAX,TG
Maximum Duty Factor for TG
DF_MAX,BG
Maximum Duty Factor for BG
I_TRACK/SS1,2
Soft-Start Charge Current
I_SS3
Soft-Start Charge Current
V_RUN1 ON
V_RUN2,3 ON
V_RUN1,2,3 Hyst
RUN1 Pin Threshold
RUN2,3 Pin Threshold
RUN Pin Hysteresis
V_{SENSE1,2,3(MAX)} Maximum Current Sense Threshold
V_SENSE3(CM)
Gate Driver
SENSE3 Pins Common Mode Range
(BOOST Converter Input Supply Voltage)
INTV_CC Ramping Up
INTV_CC Ramping Down
Measured at V_FB1,2 Relative to
Regulated V_FB1,2
Bucks (Channels 1 and 2)
Boost (Channel 3)
Bucks (Channels 1 and 2)
V_OUT1,2 < V_INTVCC – 0.5V
V_OUT1,2 > V_INTVCC + 0.5V
Boost (Channel 3)
V_SENSE3+, V_SENSE3– = 12V
Bucks (Channels 1,2) in Dropout, FREQ = 0V
Boost (Channel 3) in Overvoltage
Bucks (Channels 1,2) in Overvoltage
Boost (Channel 3)
V_TRACK/SS1,2 = 0V
V_SS3 = 0V
V_RUN1 Rising
V_RUN2,3 Rising
V_FB1,2 = 0.7V, V_SENSE1,2– = 3.3V
V_FB1,2,3 = 1.1V, V_SENSE3+ = 12V
l
4.15 4.5
V
l 3.5 3.8 4.0
V
7
10 13
%
±1
μA
170
μA
±2
μA
700
μA
±1
μA
98 99
%
100
%
100
%
96
%
0.7 1.0 1.4
μA
0.7 1.0 1.4
μA
l 1.19 1.25 1.31
V
l 1.23 1.28 1.33
V
80
mV
l 43
50
57
mV
2.5
38
V
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
TG3
Pull-Up On-Resistance
Pull-Down On-Resistance
1.2
Ω
1.0
Ω
BG3
Pull-Up On-Resistance
Pull-Down On-Resistance
1.2
Ω
1.0
Ω
TG Transition Time:
(Note 6)
TG1,2,3 t_r
TG1,2,3 t_f
Rise Time
Fall Time
C_LOAD = 3300pF
C_LOAD = 3300pF
25
ns
16
ns
BG Transition Time:
(Note 6)
BG1,2,3 t_r
BG1,2,3 t_f
Rise Time
Fall Time
C_LOAD = 3300pF
C_LOAD = 3300pF
28
ns
13
ns
TG/BG t_1D
Top Gate Off to Bottom Gate On Delay C_LOAD = 3300pF Each Driver Bucks (Channels 1, 2)
30
ns
Synchronous Switch-On Delay Time
Boost (Channel 3)
70
ns
BG/TG t_1D
Bottom Gate Off to Top Gate On Delay C_LOAD = 3300pF Each Driver Bucks (Channels 1, 2)
30
ns
Top Switch-On Delay Time
Boost (Channel 3)
70
ns
t_ON(MIN)1,2
Buck Minimum On-Time
(Note 7)
95
ns
t_ON(MIN)3
Boost Minimum On-Time
(Note 7)
120
ns
3859fa
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