Datasheet

LT8705
4
8705fb
For more information www.linear.com/LT8705
PARAMETER CONDITIONS MIN TYP MAX UNITS
SHDN Pin Bias Current V
SHDN
= 3V
V
SHDN
= 12V
0
11
1
22
µA
µA
SWEN Rising Threshold Voltage (Note 5)
l
1.156 1.206 1.256 V
SWEN Threshold Voltage Hysteresis (Note 5) 22 mV
MODE Pin Forced Continuous Mode Threshold
l
0.4 V
MODE Pin Burst Mode Range
l
1.0 1.7 V
MODE Pin Discontinuous Mode Threshold
l
2.3 V
Soft-Start Charging Current V
SS
= 0.5V 13 19 25 µA
Soft-Start Discharge Current V
SS
= 0.5V 9.5 µA
Voltage Regulator Loops (Refer to Block Diagram to Locate Amplifiers)
Regulation Voltage for FBOUT V
C
= 1.2V
l
1.193 1.207 1.222 V
Regulation Voltage for FBIN V
C
= 1.2V
l
1.184 1.205 1.226 V
Line Regulation for FBOUT and FBIN Error Amp Reference
Voltage
V
IN
= 12V to 80V; Not Switching 0.002 0.005 %/V
FBOUT Pin Bias Current Current Out of Pin 15 nA
FBOUT Error Amp EA4 g
m
315 µmho
FBOUT Error Amp EA4 Voltage Gain 220 V/V
FBIN Pin Bias Current Current Out of Pin 10 nA
FBIN Error Amp EA3 g
m
130 µmho
FBIN Error Amp EA3 Voltage Gain 90 V/V
SRVO_FBIN Activation Threshold (Note 5) (V
FBIN
Falling) – (Regulation Voltage for FBIN),
V
FBOUT
= V
IMON_IN
= V
IMON_OUT
= 0V
56 72 89 mV
SRVO_FBIN Activation Threshold Hysteresis (Note 5) V
FBOUT
= V
IMON_IN
= V
IMON_OUT
= 0V 33 mV
SRVO_FBOUT Activation Threshold (Note 5) (V
FBOUT
Rising) – (Regulation Voltage for FBOUT),
V
FBIN
= 3V, V
IMON_IN
= V
IMON_OUT
= 0V
–37 –29 –21 mV
SRVO_FBOUT Activation Threshold Hysteresis (Note 5) V
FBIN
= 3V, V
IMON_IN
= 0V, V
IMON_OUT
= 0V 15 mV
SRVO_FBIN, SRVO_FBOUT Low Voltage (Note 5) I = 100μA
l
110 330 mV
SRVO_FBIN, SRVO_FBOUT Leakage Current (Note 5) V
SRVO_FBIN
= V
SRVO_FBOUT
= 2.5V
l
0 1 µA
Current Regulation Loops (Refer to Block Diagram to Locate Amplifiers)
Regulation Voltages for IMON_IN and IMON_OUT V
C
= 1.2V
l
1.187 1.208 1.229 V
Line Regulation for IMON_IN and IMON_OUT Error Amp
Reference Voltage
V
IN
= 12V to 80V; Not Switching 0.002 0.005 %/V
CSPIN, CSNIN Bias Current BOOST Capacitor Charge Control Block Not Active
I
CSPIN
+ I
CSNIN
, V
CSPIN
= V
CSNIN
= 12V 31 µA
CSPIN, CSNIN Common Mode Operating Voltage Range
l
1.5 80 V
CSPIN, CSNIN Differential Operating Voltage Range
l
–100 100 mV
V
CSPIN-CSNIN
to IMON_IN Amplifier A7 g
m
V
CSPIN
– V
CSNIN
= 50mV, V
CSPIN
= 5.025V
l
0.95
0.94
1
1
1.05
1.06
mmho
mmho
IMON_IN Maximum Output Current
l
100 µA
IMON_IN Overvoltage Threshold
l
1.55 1.61 1.67 V
IMON_IN Error Amp EA2 g
m
185 µmho
IMON_IN Error Amp EA2 Voltage Gain 130 V/V
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 3)