LTC3780
ELECTRICAL CHARACTERISTICS
SYMBOL
DF MAX, Boost
DF MAX, Buck
V
RUN(ON)
I
SS
V
SENSE(MAX)
V
SENSE(MIN,BUCK)
TG1, TG2 t
r
TG1, TG2 t
f
BG1, BG2 t
r
BG1, BG2 t
f
TG1/BG1 t
1D
BG1/TG1 t
2D
TG2/BG2 t
3D
BG2/TG2 t
4D
Mode
Transition 1
Mode
Transition 2
t
ON(MIN,BOOST)
t
ON(MIN,BUCK)
PARAMETER
Maximum Duty Factor
Maximum Duty Factor
RUN Pin On Threshold
Soft-Start Charge Current
Maximum Current Sense Threshold
Minimum Current Sense Threshold
TG Rise Time
TG Fall Time
BG Rise Time
BG Fall Time
TG1 Off to BG1 On Delay,
Switch C On Delay
BG1 Off to TG1 On Delay,
Synchronous Switch D On Delay
TG2 Off to BG2 On Delay,
Synchronous Switch B On Delay
BG2 Off to TG2 On Delay,
Switch A On Delay
BG1 Off to BG2 On Delay,
Switch A On Delay
BG2 Off to BG1 On Delay,
Synchronous Switch D On Delay
Minimum On-Time for Main Switch in
Boost Operation
Minimum On-Time for Synchronous
Switch in Buck Operation
Internal V
CC
Voltage
Internal V
CC
Load Regulation
EXTV
CC
Switchover Voltage
EXTV
CC
Switchover Hysteresis
EXTV
CC
Switch Drop Voltage
Nominal Frequency
Lowest Frequency
Highest Frequency
PLLIN Input Resistance
Phase Detector Output Current
f
PLLIN
< f
OSC
f
PLLIN
> f
OSC
(Note 9)
I
CC
= 20mA, V
EXTVCC
= 6V
V
PLLFLTR
= 1.2V
V
PLLFLTR
= 0V
V
PLLFLTR
= 2.4V
260
170
340
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V unless otherwise noted.
CONDITIONS
% Switch C On
% Switch A On (in Dropout)
V
RUN
Rising
V
RUN
= 2V
Boost: V
OSENSE
= V
REF
– 50mV
Buck: V
OSENSE
= V
REF
– 50mV
Discontinuous Mode
C
LOAD
= 3300pF (Note 5)
C
LOAD
= 3300pF (Note 5)
C
LOAD
= 3300pF (Note 5)
C
LOAD
= 3300pF (Note 5)
C
LOAD
= 3300pF Each Driver
C
LOAD
= 3300pF Each Driver
C
LOAD
= 3300pF Each Driver
C
LOAD
= 3300pF Each Driver
C
LOAD
= 3300pF Each Driver
C
LOAD
= 3300pF Each Driver
Switch C (Note 6)
Switch B (Note 6)
l
l
MIN
TYP
99
99
MAX
UNITS
%
%
1
0.5
–95
1.5
1.2
160
–110
–6
50
45
45
55
80
80
80
80
250
250
200
180
2
185
–150
V
μA
mV
mV
mV
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Internal V
CC
Regulator
V
INTVCC
∆V
LDO(LOADREG)
V
EXTVCC
∆V
EXTVCC(HYS)
∆V
EXTVCC
f
NOM
f
LOW
f
HIGH
R
PLLIN
I
PLLLPF
7V < V
IN
< 30V, V
EXTVCC
= 5V
I
CC
= 0mA to 20mA, V
EXTVCC
= 5V
I
CC
= 20mA, V
EXTVCC
Rising
l
l
5.7
5.4
6
0.2
5.7
300
150
300
200
400
50
–15
15
6.3
2
V
%
V
mV
300
330
220
440
mV
kHz
kHz
kHz
kΩ
μA
μA
Oscillator and Phase-Locked Loop
3780fe
4
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
