LT1977EFE#TR Linear Technology, LT1977EFE#TR Datasheet - Page 3

• Manufacturer Part Number: LT1977EFE#TR
• Description: IC REG SW 1.5A HV STPDWN 16TSSOP
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LT1977EFE#TR

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.2 ~ 54 V
• Current - Output: 1.5A
• Frequency - Switching: 500kHz
• Voltage - Input: 3.3 ~ 60 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

temperature range, otherwise specifications are at T
unless otherwise noted.
SYMBOL
I
I
V
I
V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1977EFE 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
LT1977IFE is guaranteed and tested over the full –40°C to 125°C
operating junction temperature range.
Note 3: Minimum input voltage is defined as the voltage where switching
starts. Actual minimum input voltage to maintain a regulated output will
depend upon output voltage and load current. See Applications
Information.
Note 4: Supply input current is the quiescent current drawn by the input
pin. Its typical value depends on the voltage on the BIAS pin and operating
state of the LT1977. With the BIAS pin at 0V, all of the quiescent current
required to operate the LT1977 will be provided by the V
BIAS voltage above its minimum input voltage, a portion of the total
quiescent current will be supplied by the BIAS pin. Supply sleep current is
defined as the quiescent current during the “sleep” portion of Burst Mode
operation. See Applications Information for determining application supply
currents.
ELECTRICAL CHARACTERISTICS
CSS
PGFB
CT
PGFB
CT
PARAMETER
Switch On Resistance (Note 9)
Switching Frequency
Maximum Duty Cycle
Minimum SYNC Amplitude
SYNC Frequency Range
SYNC Input Impedance
C
PGFB Input Current
PGFB Voltage Threshold (Note 11)
C
C
C
PG Leakage (Note 11)
PG Sink Current (Note 11)
SS
T
T
T
Source Current (Note 11)
Sink Current (Note 11)
Voltage Threshold (Note 11)
Current Threshold (Note 10)
IN
pin. With the
CONDITIONS
FB = 0V
V
PGFB = 1V, PG = 400mV
J
PG
= 25°C. V
= 12V
The
●
IN
denotes the specifications which apply over the full operating
= 12V, SHDN = 12V, BIAS = 5V, FB/PGFB = 1.25V, C
Note 5: Minimum BIAS voltage is the voltage on the BIAS pin when I
sourced into the pin.
Note 6: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
Note 7: Boost current is the current flowing into the BOOST pin with the pin
held 3.3V above input voltage. It flows only during switch on time.
Note 8: Gain is measured with a V
Note 9: Switch on resistance is calculated by dividing V
forced current (1.5A). See Typical Performance Characteristics for the graph
of switch voltage at other currents.
Note 10: The C
C
Soft-Start section in Applications Information.
Note 11: The PGFB threshold is defined as the percentage of V
which causes the current source output of the C
sinking (below threshold) to sourcing current (above threshold). When
sourcing current, the voltage on the C
internally. When the clamp is activated, the output of the PG pin will be set
to a high impedance state. When the C
be set active low with a current sink capability of 200µA.
SS
pin which results in an increase in sink current from the V
SS
threshold is defined as the value of current sourced into the
●
●
●
C
swing from 1.15V to 750mV.
MIN
1.16
425
575
100
T
86
88
7
2
1
T
pin rises until it is clamped
clamp is inactive the PG pin will
TYP
500
200
T
0.2
1.5
3.6
1.2
0.1
92
85
13
25
90
2
pin to change from
IN
SS
to SW voltage by the
LT1977
/SYNC = 0V
MAX
1.26
575
700
100
0.4
2.0
5.5
20
92
1
C
REF
pin. See the
voltage
UNITS
BIAS
1977fa
3
kHz
kHz
mA
kΩ
µA
nA
µA
µA
µA
%
%
Ω
is
V
V