Datasheet

LT8705
5
8705fb
For more information www.linear.com/LT8705
PARAMETER CONDITIONS MIN TYP MAX UNITS
CSPOUT, CSNOUT Bias Current BOOST Capacitor Charge Control Block Not Active
I
CSPOUT
+ I
CSNOUT
, V
CSPOUT
= V
CSNOUT
= 12V
I
CSPOUT
+ I
CSNOUT
, V
CSPOUT
= V
CSNOUT
= 1.5V
45
4
µA
µA
CSPOUT, CSNOUT Common Mode Operating Voltage Range
l
0 80 V
CSPOUT, CSNOUT Differential Mode Operating Voltage Range
l
–100 100 mV
V
CSPOUT-CSNOUT
to IMON_OUT Amplifier A6 g
m
V
CSPOUT
– V
CSNOUT
= 50mV, V
CSPOUT
= 5.025V
V
CSPOUT
– V
CSNOUT
= 50mV, V
CSPOUT
= 5.025V
V
CSPOUT
– V
CSNOUT
= 5mV, V
CSPOUT
= 5.0025V
V
CSPOUT
– V
CSNOUT
= 5mV, V
CSPOUT
= 5.0025V
l
l
0.95
0.94
0.65
0.55
1
1
1
1
1.05
1.085
1.35
1.6
mmho
mmho
mmho
mmho
IMON_OUT Maximum Output Current
l
100 µA
IMON_OUT Overvoltage Threshold
l
1.55 1.61 1.67 V
IMON_OUT Error Amp EA1 g
m
185 µmho
IMON_OUT Error Amp EA1 Voltage Gain 130 V/V
SRVO_IIN Activation Threshold (Note 5) (V
IMON_IN
Rising) – (Regulation Voltage for
IMON_IN), V
FBIN
= 3V, V
FBOUT
= 0V, V
IMON_OUT
= 0V
–60 –49 –37 mV
SRVO_IIN Activation Threshold Hysteresis (Note 5) V
FBIN
= 3V, V
FBOUT
= 0V, V
IMON_OUT
= 0V 22 mV
SRVO_IOUT Activation Threshold (Note 5) (V
IMON_OUT
Rising) – (Regulation Voltage for IMON_
OUT), V
FBIN
= 3V, V
FBOUT
= 0V, V
IMON_IN
= 0V
–62 –51 –39 mV
SRVO_IOUT Activation Threshold Hysteresis (Note 5) V
FBIN
= 3V, V
FBOUT
= 0V, V
IMON_IN
= 0V 22 mV
SRVO_IIN, SRVO_IOUT Low Voltage (Note 5) I = 100μA
l
110 330 mV
SRVO_IIN, SRVO_IOUT Leakage Current (Note 5) V
SRVO_IIN
= V
SRVO_IOUT
= 2.5V
l
0 1 µA
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 100 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 100 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 265 ns
Minimum On-Time for Synchronous Switch in Buck
Operation (t
ON(M2,MIN)
)
Switch M2, C
LOAD
= 3300pF 260 ns
Minimum Off-Time for Main Switch in Steady-State Boost
Operation
Switch M3, C
LOAD
= 3300pF 245 ns
Minimum Off-Time for Synchronous Switch in
Steady-State Buck Operation
Switch M2, C
LOAD
= 3300pF 245 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
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, SHDN = 3V unless otherwise noted. (Note 2)