Linear Technology LT3956 Series, Руководство пользователя, Страница: 4 / 20

LT3956
3956f
elecTrical characTerisTics
The
l
denotes the specifications which apply over the full operating temp-
erature range, otherwise specifications are at T
A
= 25°C. V
IN
= 24V, EN/UVLO = 24V, CTRL = 2V, PWM = 5V, unless otherwise noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Logic Inputs/Outputs
PWM Threshold Voltage
l
0.85 1.35 1.8 V
PWM Pin Resistance to GND 45 60 kΩ
EN/UVLO Threshold Voltage Falling
l
1.185 1.220 1.245 V
EN/UVLO Rising Hysteresis 20 mV
EN/UVLO Input Low Voltage I
VIN
Drops Below 1µA 0.4 V
EN/UVLO Pin Bias Current Low EN/UVLO = 1.15V 1.7 2.1 2.5 µA
EN/UVLO Pin Bias Current High EN/UVLO = 1.30V 10 100 nA
VMODE Output Low (V
OL
) I
VMODE
= 1mA 200 mV
VMODE Pin Leakage FB = 0V, VMODE = 12V 0.1 5 µA
PWMOUT Driver
t
r
PWMOUT Driver Output Rise Time C
L
= 560pF 35 ns
t
f
PWMOUT Driver Output Fall Time C
L
= 560pF 35 ns
PWMOUT Output Low (V
OL
) 0.05 V
PWMOUT Output High (V
OH
) INTV
CC
–
0.05
V
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: The LT3956E is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT3956I is guaranteed to meet performance specifications over the –40°C
to 125°C operating junction temperature range.
Note 3: For V
IN
below 6V, the EN/UVLO pin must not exceed V
IN
for proper
operation.
V
(ISP–ISN)
Threshold vs V
CTRL
V
(ISP–ISN)
Threshold vs V
ISP
with Reduced CTRL Voltage
V
(ISP–ISN)
Full-Scale Threshold
vs Temperature
CTRL VOLTAGE (V)
0
–50
V
(IS
P
–ISN)
THRESHOLD (mV)
50
150
250
0.5 1 1.5
300
0
100
200
2
3956 G01
ISP VOLTAGE (V)
0
97
V
(IS
P
–ISN)
THRESHOLD (mV)
99
101
20 40 80 60
103
98
100
102
3956 G02
CTRL = 0.5V
242
246
250
256
254
244
248
252
3956 G03
V
(IS
P
–ISN)
THRESHOLD (mV)
TEMPERATURE (°C)
–50 0 50 75
–25
25 100 125
CTRL = 2V
Typical perForMance characTerisTics
T
A
= 25°C, unless otherwise noted.