Datasheet

LTC4217
4
4217fe
elecTrical characTerisTics
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: All currents into pins are positive, all voltages are referenced to
GND unless otherwise specified.
Note 3: An internal clamp limits the GATE pin to a maximum of 6.5V above
OUT. Driving this pin to voltages beyond the clamp may damage the device.
Note 4: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD
= 12V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Inputs
I
IN
OV, UV, FB Pin Input Current V
IN
= 1.2V, LTC4217
l
0 ±1 µA
R
IN
OV, UV, FB Pin Input Resistance LTC4217-12
l
13 18 23 kΩ
V
TH
OV, UV, FB Pin Threshold Voltage V
IN
Rising
l
1.21 1.235 1.26 V
∆V
OV(HYST)
OV Pin Hysteresis
l
10 20 30 mV
∆V
UV(HYST)
UV Pin Hysteresis
l
50 80 110 mV
V
UV(RTH)
UV Pin Reset Threshold Voltage V
UV
Falling
l
0.55 0.62 0.7 V
∆V
FB(HYST)
FB Pin Power Good Hysteresis
l
10 20 30 mV
R
ISET
I
SET
Pin Output Resistor
l
19 20 21 kΩ
Outputs
V
OL
PG, F LT Pin Output Low Voltage I
OUT
= 2mA
C-Grade, I-Grade
H-Grade
l
l
0.4
0.4
0.8
0.92
V
V
I
OH
PG, F LT Pin Input Leakage Current V
OUT
= 30V
l
0 ±10 µA
V
TIMER(H)
TIMER Pin High Threshold V
TIMER
Rising
l
1.2 1.235 1.28 V
V
TIMER(L)
TIMER Pin Low Threshold V
TIMER
Falling
l
0.1 0.21 0.3 V
I
TIMER(UP)
TIMER Pin Pull-Up Current V
TIMER
= 0V
l
–80 –100 –120 µA
I
TIMER(DN)
TIMER Pin Pull-Down Current V
TIMER
= 1.2V
l
1.4 2 2.6 µA
I
TIMER(RATIO)
TIMER Pin Current Ratio I
TIMER(DN)
/I
TIMER(UP)
l
1.6 2 2.7 %
A
IMON
I
MON
Pin Current Gain I
OUT
= 2A
l
47.5 50 52.5 µA/A
I
OFF(IMON)
I
MON
Pin Offset Current I
OUT
= 132mA
l
0 ±7.5 µA
I
GATE(UP)
Gate Pull-Up Current Gate Drive On, V
GATE
= V
OUT
= 12V
l
–19 –24 –29 µA
I
GATE(DN)
Gate Pull-Down Current Gate Drive Off, V
GATE
= 18V, V
OUT
= 12V
C-Grade, I-Grade
H-Grade
l
l
190
164
250
140
340
355
µA
µA
I
GATE(FST)
Gate Fast Pull-Down Current Fast Turn Off, V
GATE
= 18V, V
OUT
= 12V 140 mA
AC Characteristics
t
PHL(GATE)
Input High (OV), Input Low (UV) to Gate Low
Propagation Delay
V
GATE
< 16.5V Falling
l
8 10 µs
t
PHL(ILIM)
Short-Circuit to Gate Low V
FB
= 0, Step I
SENSE
to 1.2A,
V
GATE
< 16.5V Falling
l
1 5 µs
t
D(ON)
Turn-On Delay Step V
UV
to 2V, V
GATE
> 13V
l
50 100 150 ms
t
D(CB)
Circuit Breaker Filter Delay Time (Internal) V
FB
= 0V, Step I
SENSE
to 1.2A
C-Grade, I-Grade
H-Grade
l
l
1.5
1.4
2
2
2.7
2.7
ms
ms
t
D(AUTO-RETRY)
Auto-Retry Turn-On Delay (Internal)
l
50 100 150 ms
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 5: T
J
is calculated from the ambient temperature, T
A
, and power
dissipation, P
D
, according to the formula:
LTC4217DHC, LTC4217DHC-12: T
J
= T
A
+ (P
D
• 43°C/W)
LTC4217FE: T
J
= T
A
+ (P
D
• 38°C/W)
Note 6: For the DHC package, switch on-resistance is guaranteed by
design and test correlation.