LTC1267CG-ADJ Ver la hoja de datos (PDF) - Linear Technology
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LTC1267CG-ADJ Datasheet PDF : 16 Pages
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LTC1267
LTC1267-ADJ/LTC1267-ADJ5
ELECTRICAL CHARACTERISTICS
– 40°C ≤ TA ≤ 85°C, VIN = 12V, VMSHDN, VSHDN1,3,5 = 0V (Notes 2, 5), unless otherwise noted.
SYMBOL
VFB1, 2
VOUT
IIN
IEXTVCC
VCC
VSENSE
VSENSE
+
–
–
VMSHDN
tOFF
PARAMETER
Feedback Voltage
Regulated Output Voltage
3.3V Output
5V Output
VIN Pin Current (Note 3)
Normal
Shutdown
EXT VCC Pin Current (Note 3)
Internal Regulator Voltage
Current Sense Threshold Voltage
Shutdown Threshold MSHDN
Off-Time (Note 4)
CONDITIONS
LTC1267-ADJ, LTC1267-ADJ5: VIN = 9V
VIN = 9V
ILOAD = 700mA
ILOAD = 700mA
VIN = 12V, EXT VCC = 5V
VIN = 40V, EXT VCC = 5V
VIN = 12V, VMSHDN = 2V
VIN = 40V, VMSHDN = 2V
EXT VCC = 5V, Sleep Mode
VIN = 12V to 40V, EXT VCC = 0V, ICC = 20mA
Low Threshold (Forced)
High Threshold (Forced)
CT = 390pF, ILOAD = 700mA, VIN = 10V
MIN TYP MAX
1.2 1.25 1.3
UNITS
V
3.17 3.30 3.48
V
4.85 5.05 5.25
V
320
µA
550
µA
15
µA
25
µA
360
µA
4.5
V
25
mV
130 160 185
mV
0.8 1.4 2.0
V
3
5
7
µs
The q denotes specifications which apply over the full operating
temperature range.
Note 1: TJ is calculated from the ambient temperature TA and power
dissipation PD according to the following formula:
LTC1267/LTC1267-ADJ/LTC1267ADJ5: TJ = TA + (PD × 95°C/ W)
Note 2: On LTC1267 versions which have MSHDN and SHDN1, 3, 5 pins,
they must be at ground potential for testing.
Note 3: The LTC1267 VIN and EXT VCC current measurements exclude
MOSFET driver currents. When VCC power is derived from the output via
EXT VCC, the input current increases by (IGATECHG × Duty Cycle)/Efficiency.
See Typical Performance Characteristics and Applications Information.
Note 4: In applications where RSENSE is placed at ground potential, the
off-time increases approximately 40%.
Note 5: The LTC1267/LTC1267-ADJ/LTC1267-ADJ5 are not tested and
quality-assurance sampled at – 40°C to 85°C. These specifications are
guaranteed by design and/or correlation.
Note 6: The logic level power MOSFETs shown in Figure 1 are rated for
VDS(MAX) = 30V. For operation at VIN > 30V, use standard threshold
MOSFETs with EXT VCC powered from a 9V supply. See applications
information.
Note 7: LTC1267-ADJ and LTC1267-ADJ5 are tested at an output of 3.3V
TYPICAL PERFORMANCE CHARACTERISTICS
5V Output Efficiency
vs Load Current
100
95
VIN = 10V
90
85
VIN = 20V
80
75
70
65
60
0.01
0.1
1
LOAD CURRENT (A)
10
LTC1267 • G01
3.3V Output Efficiency
vs Load Current
100
95
VIN = 10V
90
85
VIN = 20V
80
75
70
65
60
0.01
0.1
1
LOAD CURRENT (A)
10
LTC1267 • G02
Load Regulation
30
20
10
VIN = 20V
0
VOUT = 3.3V
VIN = 10V
–10
VOUT = 3.3V
–20
VIN = 10V
VOUT = 5V
–30
VIN = 20V
–40
VOUT = 5V
–50
–60
0
0.5
1.0
1.5
LOAD CURRENT
2.0 2.5
LTC1267 • G03
4
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