LT8708
7
Rev 0
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
IMON_OP, IMON_ON, ICP and ICN Max
Output Current
l
120
μA
IMON_OP Error Amp EA6 g
m
190
μmho
IMON_OP Error Amp EA6 Voltage Gain
130
V/V
IMON_ON Error Amp EA2 gm
FBIN = 0V, FBOUT = 3.3V
190
μmho
IMON_ON Error Amp EA2 Voltage Gain
FBIN = 0V, FBOUT = 3.3V
130
V/V
NMOS Gate Drivers
TG1, TG2 Rise Time
C
LOAD
= 3300pF (Note 4)
20
ns
TG1, TG2 Fall Time
C
LOAD
= 3300pF (Note 4)
20
ns
BG1, BG2 Rise Time
C
LOAD
= 3300pF (Note 4)
20
ns
BG1, BG2 Fall Time
C
LOAD
= 3300pF (Note 4)
20
ns
TG1 Off to BG1 On Delay
C
LOAD
= 3300pF Each Driver
90
ns
BG1 Off to TG1 On Delay
C
LOAD
= 3300pF Each Driver
80
ns
TG2 Off to BG2 On Delay
C
LOAD
= 3300pF Each Driver
90
ns
BG2 Off to TG2 On Delay
C
LOAD
= 3300pF Each Driver
80
ns
Minimum On-Time for Main Switch in Boost
Operation (t
ON(M3,MIN)
)
Switch M3, C
LOAD
= 3300pF
200
ns
Minimum On-Time for Synchronous Switch in Buck
Operation (t
ON(M2,MIN)
)
Switch M2, C
LOAD
= 3300pF
200
ns
Minimum Off-Time for Main Switch in Steady-State
Boost Operation
Switch M3, C
LOAD
= 3300pF
230
ns
Minimum Off-Time for Synchronous Switch in
Steady-State Buck Operation
Switch M2, C
LOAD
= 3300pF
230
ns
Oscillator
Switch Frequency Range
SYNCing or Free Running
100
400
kHz
Switching Frequency, F
OSC
R
T
= 365k
R
T
= 215k
R
T
= 124k
l
l
l
102
170
310
120
202
350
142
235
400
kHz
kHz
kHz
SYNC High Level for Synchronization
l
1.3
V
SYNC Low Level for Synchronization
l
0.5
V
SYNC Clock Pulse Duty Cycle
V
SYNC
= 0V to 2V
20
80
%
Recommended Min SYNC Ratio F
SYNC
/F
OSC
3/4
CLKOUT Output Voltage High
V
LDO33
– V
CLKOUT
, 1mA Out of CLKOUT Pin,
I
LDO33
= 0μA
100
250
mV
CLKOUT Output Voltage Low
1mA Into CLKOUT Pin
25
100
mV
CLKOUT Duty Cycle
T
J
= –40°C
T
J
= 25°C
T
J
= 125°C
22.7
44.1
77
%
%
%
ELECTRICAL CHARACTERISTICS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
INCHIP
= 12V,
SHDN
= 3V, DIR = 3.3V unless otherwise noted (Note 3).
