Datasheet

LTC4008
4
4008fb
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
DCIN
= 20V, V
BAT
= 12V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Input P-Channel FET Driver (INFET) (LTC4008 Only)
DCIN Detection Threshold (V
DCIN
– V
CLP
) DCIN Voltage Ramping Up
from V
CLP
– 0.1V
l
0 0.17 0.25 V
Forward Regulation Voltage (V
DCIN
– V
CLP
)
l
25 50 mV
Reverse Voltage Turn-Off Voltage (V
DCIN
– V
CLP
) DCIN Voltage Ramping Down
l
–60 –25 mV
INFET “On” Clamping Voltage (V
CLP
– V
INFET
)I
INFET
= 1μA
l
5 5.8 6.5 V
INFET “Off” Clamping Voltage (V
CLP
– V
INFET
)I
INFET
= –25μA 0.25 V
Thermistor
NTCVR Reference Voltage During Sample Time 4.5 V
High Threshold V
NTC
Rising
l
NTCVR
• 0.48
NTCVR
• 0.5
NTCVR
• 0.52
V
Low Threshold V
NTC
Falling
l
NTCVR
• 0.115
NTCVR
• 0.125
NTCVR
• 0.135
V
Thermistor Disable Current V
NTC
≤ 10V 10 μA
Indicator Outputs (ACP/SHDN, FLAG, I
CL
, FAULT
C10TOL FLAG (C/10) Accuracy Voltage Falling at PROG
l
0.375 0.397 0.420 V
I
CL
Threshold Accuracy V
CLP
– V
CLN
83 93 105 mV
V
OL
Low Logic Level of ACP/SHDN, FLAG, I
CL
, FAULT I
OL
= 100μA 0.5 V
V
OH
High Logic Level of ACP/SHDN, I
CL
I
OH
= –1μA
l
2.7 V
I
OFF
Off State Leakage Current of FLAG, FAULT V
OH
= 3V –1 1 μA
I
PO
Pull-Up Current on ACP/SHDN, I
CL
V = 0V –10 μA
Oscillator
f
OSC
Regulator Switching Frequency 255 300 345 kHz
f
MIN
Regulator Switching Frequency in Drop Out Duty Cycle ≥ 98% 20 25 kHz
DC
MAX
Regulator Maximum Duty Cycle V
CSP
= V
BAT
98 99 %
Gate Drivers (TGATE, BGATE)
V
TGATE
High (V
CLP
– V
TGATE
)I
TGATE
= –1mA 50 mV
V
BGATE
High C
LOAD
= 3000pF 5.6 10 V
V
TGATE
Low (V
CLP
– V
TGATE
)C
LOAD
= 3000pF 5.6 10 V
V
BGATE
Low I
BGATE
= 1mA 50 mV
TGTR
TGTF
TGATE Transition Time
TGATE Rise Time
TGATE Fall Time
C
LOAD
= 3000pF, 10% to 90%
C
LOAD
= 3000pF, 10% to 90%
50
50
110
100
ns
ns
BGTR
BGTF
BGATE Transition Time
BGATE Rise Time
BGATE Fall Time
C
LOAD
= 3000pF, 10% to 90%
C
LOAD
= 3000pF, 10% to 90%
40
40
90
80
ns
ns
V
TGATE
at Shutdown (V
CLP
– V
TGATE
)I
TGATE
= –1μA, DCIN = 0V, CLP = 12V 100 mV
V
BGATE
at Shutdown I
BGATE
= 1μA, DCIN = 0V, CLP = 12V 100 mV
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: See Test Circuit.
Note 3: Does not include tolerance of current sense resistor or current
programming resistor.
Note 4: The LTC4008E is guaranteed to meet performance specifi cations
from 0°C to 70°C. Specifi cations over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 5: Voltage accuracy includes BATMON error and voltage reference
error. Does not include error of external resistor divider.