LT3959
4
3959fa
For more information www.linear.com/LT3959
PARAMETER CONDITIONS MIN TYP MAX UNITS
SYNC Input Low
l
0.4 V
SYNC Input High
l
1.5 V
SS Pull-Up Current SS = 0V, Current Out of Pin
l
–14 –10.5 –7 µA
Low Dropout Regulators (DRIVE LDO and V
IN
LDO)
DRIVE LDO Regulation Voltage DRIVE = 6V, Not Switching
l
4.6 4.75 4.9 V
V
IN
LDO Regulation Voltage DRIVE = 0V, Not Switching
l
3.6 3.75 3.9 V
DRIVE LDO Current Limit INTV
CC
= 4V 60 mA
V
IN
LDO Current Limit DRIVE = 0V, INTV
CC
= 3V 60 mA
DRIVE LDO Load Regulation (∆V
INTVCC
/V
INTVCC
) 0 < I
INTVCC
< 20mA, DRIVE = 6V –1 –0.6 %
V
IN
LDO Load Regulation (∆V
INTVCC
/V
INTVCC
) DRIVE = 0V, 0 < I
INTVCC
< 20mA –1 –0.6 %
DRIVE LDO Line Regulation [∆V
INTVCC
/(V
INTVCC
• ∆V
IN
)] 1.6V < V
IN
< 40V, DRIVE = 6V 0.03 0.07 %/V
V
IN
LDO Line Regulation [∆V
INTVCC
/(V
INTVCC
• ∆V
IN
)] DRIVE = 0V, 5V < V
IN
< 40V 0.03 0.07 %/V
DRIVE LDO Dropout Voltage (V
DRIVE
– V
INTVCC
) DRIVE = 4V, I
INTVCC
= 20mA
l
190 400 mV
V
IN
LDO Dropout Voltage (V
IN
– V
INTVCC
) V
IN
= 3V, DRIVE = 0V,
I
INTVCC
= 20mA
l
190 400 mV
INTV
CC
Undervoltage Lockout Threshold Falling
l
1.85 2.0 2.15 V
INTV
CC
Undervoltage Lockout Threshold Rising
l
2.15 2.3 2.45 V
INTV
CC
Current in Shutdown EN/UVLO = 0V 25 µA
Logic
EN/UVLO Threshold Voltage Falling
l
1.17 1.22 1.27 V
EN/UVLO Threshold Voltage Rising Hysteresis 20 mV
EN/UVLO Input Low Voltage I
VIN
< 1μA 0.4 V
EN/UVLO Pin Bias Current Low EN/UVLO = 1.15V 1.8 2.2
2.6 µA
EN/UVLO Pin Bias Current High EN/UVLO = 1.30V 10 100 nA
FBX Power Good Threshold Voltage FBX > 0V, PGOOD Falling
FBX < 0V, PGOOD Falling
V
FBX(REG)
– 0.08
V
FBX(REG)
+ 0.04
V
V
FBX Overvoltage Threshold FBX > 0V, PGOOD Rising
FBX < 0V, PGOOD Rising
V
FBX(REG)
+ 0.12
V
FBX(REG)
– 0.06
V
V
PGOOD Output Low (V
OL
) I
PGOOD
= 250µA 210 300 mV
PGOOD Leakage Current PGOOD = 40V 1 µA
INTV
CC
Minimum Voltage to Enable PGOOD Function
l
2.5 2.7 2.9 V
INTV
CC
Minimum Voltage to Enable SYNC Function
l
2.5 2.7 2.9 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, EN/UVLO = 12V, INTV
CC
= 4.75V, unless otherwise noted.
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: For V
IN
below 4V, the EN/UVLO pin must not exceed V
IN
for proper
operation.
Note 3: The LT3959E is guaranteed to meet performance specifications
from the 0°C to 125°C operating 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 LT3959I is guaranteed over the full –40°C to 125°C operating junction
temperature range.
Note 4:
The LT3959 is tested in a feedback loop which servos V
FBX
to the
reference voltages (1.6V and –0.8V) with the V
C
pin forced to 1.3V.
