LTM4605
4
4605fd
For more information www.linear.com/LTM4605
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), V
IN
= 12V. Per typical application (front page) configuration.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Control Section
V
FB
Feedback Reference Voltage V
COMP
= 1.2V
l
0.792 0.8 0.808 V
V
RUN
RUN Pin ON/OFF Threshold 1 1.6 2.2 V
I
SS
Soft-Start Charging Current V
RUN
= 2.2V 1 1.7 µA
V
STBYMD(START)
Start-Up Threshold V
STBYMD
Rising 0.4 0.7 V
V
STBYMD(KA)
Keep-Active Power On Threshold V
STBYMD
Rising, V
RUN
= 0V 1.25 V
V
FCB
Forced Continuous Threshold 0.76 0.8 0.84 V
I
FCB
Forced Continuous Pin Current V
FCB
= 0.85V –0.3 –0.2 –0.1 µA
V
BURST
Burst Inhibit (Constant Frequency)
Threshold
Measured at FCB Pin 5.3 5.5 V
DF
(BOOST, MAX)
Maximum Duty Factor % Switch M4 On 99 %
DF
(BUCK, MAX)
Maximum Duty Factor % Switch M1 On 99 %
t
ON(MIN, BUCK)
Minimum On-Time for Synchronous
Switch in Buck Operation
Switch M1 (Note 5) 200 250 ns
RFBHI Resistor Between V
OUT
and V
FB
Pins 99.5 100 100.5 kΩ
Internal V
CC
Regulator
INTV
CC
Internal V
CC
Voltage V
IN
> 7V, V
EXTVCC
= 5V
l
5.7 6 6.3 V
ΔV
LDO
/V
LDO
Internal V
CC
Load Regulation I
CC
= 0mA to 20mA, V
EXTVCC
= 5V 0.3 2 %
V
EXTVCC
EXTV
CC
Switchover Voltage I
CC
= 20mA, V
EXTVCC
Rising
l
5.4 5.6 V
ΔV
EXTVCC(HYS)
EXTV
CC
Switchover Hysteresis 300 mV
ΔV
EXTVCC
EXTV
CC
Switch Drop Voltage I
CC
= 20mA, V
EXTVCC
= 6V 60 150 mV
Current Sensing Section
V
SENSE(MAX)
Maximum Current Sense Threshold Boost Mode
Buck Mode
l
l
–95
160
–130
190
–150
mV
mV
V
SENSE(MIN, BUCK)
Minimum Current Sense Threshold Discontinuous Mode –6 mV
I
SENSE
Sense Pins Total Source Current V
SENSE
–
= V
SENSE
+
= 0V –380 µA
PGOOD
ΔV
FBH
PGOOD Upper Threshold V
FB
Rising 5.5 7.5 10 %
ΔV
FBL
PGOOD Lower Threshold V
FB
Falling –5.5 –7.5 –10 %
ΔV
FB(HYS)
PGOOD Hysteresis V
FB
Returning 2.5 %
V
PGL
PGOOD Low Voltage I
PGOOD
= 2mA 0.2 0.3 V
I
PGOOD
PGOOD Leakage Current V
PGOOD
= 5V 1 µA
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 LTM4605E is guaranteed to meet specifications from the 0°C
to 85°C operating temperature range. Specifications over the –40°C to
85°C operating temperature range are assured by design, characterization
and correlation with statistical process controls. The LTM4605I is
guaranteed over the –40°C to 85°C operating temperature range.
Note 3: The LTM4605 is tested in a feedback loop that servos V
COMP
to a
specified voltage and measures the resultant V
FB
.
Note 4: Turn-on and turn-off time are measured using 10% and 90%
levels. Transition delay time is measured using 50% levels.
Note 5: 100% tested at wafer level only.
Note 6: Absolute Maximum Rating of –5V on SW1
and SW2 is under
transient condition only.
