LT1076-5 Datasheet, PDF (3/4 Pages) Linear Technology – 5V Step-Down Switching Regulator

LT1076-5
ELECTRICAL CHARACTERISTICS T_J = 25°C, V_IN = 25V, unless otherwise noted.
PARAMETER
Switching Frequency
Switching Frequency Line Regulation
Error Amplifier Voltage Gain (Note 7)
Error Amplifier Transconductance (Note 7)
Error Amplifier Source and Sink Current
Sense Pin Divider Resistance
Sense Voltage
Output Voltage Tolerance
Output Voltage Line Regulation
V_C Voltage at 0% Duty Cycle
Multiplier Reference Voltage
Shutdown Pin Current
Shutdown Thresholds
Thermal Resistance Junction to Case
CONDITIONS
T_J ≤ 125°C
V_OUT = V_SENSE = 0V (Note 4)
8V ≤ V_IN ≤ V_MAX (Note 7)
1V ≤ V_C ≤ 4V
Source (V_SENSE = 4.5V)
Sink (V_SENSE = 5.5V)
V_C = 2V
V_OUT (Nominal) = 5V
All Conditions of Input Voltage, Output Voltage,
Temperature and Load Current
8V ≤ V_IN ≤ V_MAX (Note 6)
Over Temperature
V_SHDN = 5V
V_SHDN ≤ V_THRESHOLD (≅ 2.5V)
Switch Duty Cycle = 0
Fully Shut Down
MIN TYP MAX
90 100 110
q
85
120
20
q
0.03 0.1
2000
3700 5000 8000
100 140 225
0.7 1.0 1.6
3
5
8
q 4.85 5 5.15
±0.5 ±2
q
±1.0 ±3
q
0.005 0.02
1.5
q
– 4.0
24
5
10 20
50
2.2 2.45 2.7
0.1 0.30 0.5
4
UNITS
kHz
kHz
kHz
%/ V
V/ V
µmho
µA
mA
kΩ
V
%
%
%/ V
V
mV/°C
V
µA
µA
V
V
°C/ W
The q denotes specifications which apply over the full operating
temperature range.
Note 1: To calculate maximum switch “on” voltage at currents between
low and high conditions, a linear interpolation may be used.
Note 2: A sense pin voltage (V_SENSE) of 5.5V forces the V_C pin to its low
clamp level and the switch duty cycle to zero. This approximates the zero
load condition where duty cycle approaches zero.
Note 3: Total voltage from V_IN pin to ground pin must be ≥ 8V after start-
up for proper regulation. For T_A < 25°C, limit = 5V.
Note 4: Switch frequency is internally scaled down when the sense pin
voltage is less than 2.6V to avoid extremely short switch on times. During
current limit testing, V_SENSE is adjusted to give a minimum switch on time
of 1µs.
Note 5: Switch to input voltage limitation must also be observed.
Note 6: V_MAX = 40V for the LT1076-5 and 60V for the LT1076HV-5.
Note 7: Error amplifier voltage gain and transconductance are specified
relative to the internal feedback node. To calculate gain and
transconductance from the Sense pin (Output) to the V_C pin, multiply by
0.44.
Note 8: Does not include switch leakage.
Note
9:
I_LIM
≈
R_LIM –
5k
1k
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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