Datasheet

LTC4252-1/LTC4252-2
LTC4252A-1/LTC4252A-2
3
425212fe
For more information www.linear.com/LTC4252-1
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 2)
SYMBOL PARAMETER CONDITIONS
LTC4252-1/-2 LTC4252A-1/-2
UNITSMIN TYP MAX MIN TYP MAX
V
Z
V
IN
– V
EE
Zener Voltage I
IN
= 2mA
l
11.5 13 14.5 11.5 13 14.5 V
r
Z
V
IN
– V
EE
Zener Dynamic Impedance I
IN
= 2mA to 30mA 5 5 Ω
I
IN
V
IN
Supply Current UV = OV = 4V, V
IN
= (V
Z
– 0.3V)
●
0.8 2 0.9 2 mA
V
LKO
V
IN
Undervoltage Lockout Coming Out of UVLO (Rising V
IN
)
●
9.2 11.5 9 10 V
V
LKH
V
IN
Undervoltage Lockout Hysteresis 1 0.5 V
V
CB
Circuit Breaker Current Limit Voltage V
CB
= (V
SENSE
– V
EE
)
●
40 50 60 45 50 55 mV
V
ACL
Analog Current Limit Voltage V
ACL
= (V
SENSE
– V
EE
),
SS = Open or 2.2V
●
80 100 120 mV
V
ACL
/
V
CB
Analog Current Limit Voltage/
Circuit Breaker Voltage
V
ACL
= (V
SENSE
– V
EE
),
SS = Open or 1.4V
●
1.05 1.20 1.38 V/V
V
FCL
Fast Current Limit Voltage V
FCL
= (V
SENSE
– V
EE
)
●
150 200 300 150 200 300 mV
V
SS
SS Voltage After End of SS Timing Cycle 2.2 1.4 V
R
SS
SS Output Impedance 100 50 kΩ
I
SS
SS Pin Current UV = OV = 4V, V
SENSE
= V
EE
,
V
SS
= 0V (Sourcing)
22 28 µA
UV = OV = 0V, V
SENSE
= V
EE
,
V
SS
= 2V (Sinking)
28 28 mA
V
OS
Analog Current Limit Offset Voltage 10 10 mV
V
ACL
+V
OS
/
V
SS
Ratio (V
ACL
+ V
OS
) to SS Voltage 0.05 0.05 V/V
I
GATE
GATE Pin Output Current UV = OV = 4V, V
SENSE
= V
EE
,
V
GATE
= 0V (Sourcing)
●
40 58 80 40 58 80 µA
UV = OV = 4V, V
SENSE
– V
EE
= 0.15V,
V
GATE
= 3V (Sinking)
17 17 mA
UV = OV = 4V, V
SENSE
– V
EE
= 0.3V,
V
GATE
= 1V (Sinking)
190 190 mA
V
GATE
External MOSFET Gate Drive V
GATE
– V
EE
, I
IN
= 2mA
●
10 12 V
Z
10 12 V
Z
V
V
GATEH
Gate High Threshold V
GATEH
= V
IN
– V
GATE
, I
IN
= 2mA,
for PWRGD Status (MS Only)
2.8 2.8 V
V
GATEL
Gate Low Threshold (Before Gate Ramp-Up) 0.5 0.5 V
V
UVHI
UV Pin Threshold HIGH
●
3.075 3.225 3.375 V
V
UVLO
UV Pin Threshold LOW
●
2.775 2.925 3.075 V
V
UV
UV Pin Threshold Low-to-High Transition
●
3.05 3.08 3.11 V
V
UVHST
UV Pin Hysteresis (● for LTC4252A Only)
●
300 292 324 356 mV
V
OVHI
OV Pin Threshold HIGH
●
5.85 6.15 6.45 V
V
OVLO
OV Pin Threshold LOW
●
5.25 5.55 5.85 V
V
OV
OV Pin Threshold Low-to-High Transition
●
5.04 5.09 5.14 V
V
OVHST
OV Pin Hysteresis (● for LTC4252A Only)
●
600 82 102 122 mV
I
SENSE
SENSE Pin Input Current UV = OV = 4V, V
SENSE
= 50mV
●
–15 –30 –15 –30 µA
I
INP
UV, OV Pin Input Current UV = OV = 4V
●
±0.1 ±1 ±0.1 ±1 µA
V
TMRH
TIMER Pin Voltage High Threshold 4 4 V
V
TMRL
TIMER Pin Voltage Low Threshold 1 1 V