LT8705
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, SHDN = 3V unless otherwise noted. (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
CSPOUT, CSNOUT Bias Current
BOOST Capacitor Charge Control Block Not Active
I
I
+ I
+ I
, V
= V
= V
= 12V
45
4
µA
µA
CSPOUT
CSPOUT
CSNOUT CSPOUT
CSNOUT CSPOUT
CSNOUT
CSNOUT
, V
= 1.5V
l
l
CSPOUT, CSNOUT Common Mode Operating Voltage Range
CSPOUT, CSNOUT Differential Mode Operating Voltage Range
0
80
V
mV
–100
100
V
to IMON_OUT Amplifier A6 g
V
V
V
V
– V
– V
– V
– V
= 50mV, V
= 50mV, V
= 5.052V
= 5.025V
0.95
0.94
0.65
0.55
1
1
1
1
1.05
mmho
CSPOUT-CSNOUT
m
CSPOUT
CSPOUT
CSPOUT
CSPOUT
CSNOUT
CSNOUT
CSNOUT
CSNOUT
CSPOUT
CSPOUT
l
1.085 mmho
= 5mV, V
= 5mV, V
= 5.0025V
= 5.0025V
1.35
1.6
mmho
mmho
CSPOUT
CSPOUT
l
l
l
IMON_OUT Maximum Output Current
IMON_OUT Overvoltage Threshold
100
µA
V
1.55
1.61
185
130
–49
1.67
IMON_OUT Error Amp EA1 g
µmho
V/V
m
IMON_OUT Error Amp EA1 Voltage Gain
SRVO_IIN Activation Threshold (Note 5)
(V
Rising) – (Regulation Voltage for
–60
–62
–37
–39
mV
IMON_IN
IMON_IN), V
= 3V, V
= 0V, V
= 0V
IMON_OUT
FBIN
FBOUT
SRVO_IIN Activation Threshold Hysteresis (Note 5)
SRVO_IOUT Activation Threshold (Note 5)
V
= 3V, V
= 0V, V = 0V
IMON_OUT
22
mV
mV
FBIN
FBOUT
(V
OUT), V
Rising) – (Regulation Voltage for IMON_
–51
IMON_OUT
= 3V, V
= 0V, V
= 0V
IMON_IN
FBIN
FBOUT
SRVO_IOUT Activation Threshold Hystersis (Note 5)
SRVO_IIN, SRVO_IOUT Low Voltage (Note 5)
SRVO_IIN, SRVO_IOUT Leakage Current (Note 5)
NMOS Gate Drivers
V
= 3V, V
= 0V, V
= 0V
22
110
0
mV
mV
µA
FBIN
FBOUT
IMON_IN
l
l
I = 100μA
330
1
V
= V
= 2.5V
SRVO_IOUT
SRVO_IIN
TG1, TG2 Rise Time
C
C
C
C
C
C
C
C
= 3300pF (Note 4)
= 3300pF (Note 4)
= 3300pF (Note 4)
= 3300pF (Note 4)
= 3300pF Each Driver
= 3300pF Each Driver
= 3300pF Each Driver
= 3300pF Each Driver
20
20
ns
ns
ns
ns
ns
ns
ns
ns
ns
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
LOAD
TG1, TG2 Fall Time
BG1, BG2 Rise Time
20
BG1, BG2 Fall Time
20
TG1 Off to BG1 On Delay
100
80
BG1 Off to TG1 On Delay
TG2 Off to BG2 On Delay
100
80
BG2 Off to TG2 On Delay
Minimum On-Time for Main Switch in Boost Operation
Switch M3, C
Switch M2, C
Switch M3, C
Switch M2, C
= 3300pF
= 3300pF
= 3300pF
= 3300pF
265
LOAD
LOAD
LOAD
LOAD
(t
)
ON(M3,MIN)
Minimum On-Time for Synchronous Switch in Buck
Operation (t
260
245
245
ns
ns
ns
)
ON(M2,MIN)
Minimum Off-Time for Main Switch in Steady-State Boost
Operation
Minimum Off-Time for Synchronous Switch in
Steady-State Buck Operation
Oscillator
Switch Frequency Range
SYNCing or Free Running
R = 365k
100
400
kHz
l
l
l
Switching Frequency, f
102
170
310
120
202
350
142
235
400
kHz
kHz
kHz
OSC
T
R = 215k
T
R = 124K
T
8705p
5
For more information www.linear.com/8705
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