LT1576IS8 Linear Technology, LT1576IS8 Datasheet - Page 3

• Manufacturer Part Number: LT1576IS8
• Description: IC SW REG STEP-DOWN 200KHZ 8SOIC
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LT1576IS8

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: Adj to 1.2V
• Current - Output: 1.5A
• Frequency - Switching: 200kHz
• Voltage - Input: 5 ~ 25 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

ELECTRICAL CHARACTERISTICS
range, otherwise specifications are T
PARAMETER
Minimum Switch Duty Cycle (Note 10)
Switch Frequency
Switch Frequency Line Regulation
Frequency Shifting Threshold on FB Pin
Minimum Input Voltage (Note 3)
Minimum Boost Voltage (Note 4)
Boost Current (Note 5)
V
BIAS Supply Current (Note 6)
Shutdown Supply Current
Lockout Threshold
Shutdown Thresholds
Synchronization Threshold
Synchronizing Range
SYNC Pin Input Resistance
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Gain is measured with a V
switching threshold level to 200mV below the upper clamp level.
Note 3: Minimum input voltage is not measured directly, but is guaranteed
by other tests. It is defined as the voltage where internal bias lines are still
regulated so that the reference voltage and oscillator frequency remain
constant. Actual minimum input voltage to maintain a regulated output will
depend on output voltage and load current. See Applications Information.
Note 4: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
Note 5: Boost current is the current flowing into the boost pin with the pin
held 5V above input voltage. It flows only during switch on time.
Note 6: V
at 5V and switching is disabled. Total input referred supply current is
calculated by summing input supply current (I
supply current (I
with V
If the BIAS pin is unavailable or open circuit, the sum of V
supply currents will be drawn by the V
IN
Supply Current (Note 6)
I
TOT
IN
= I
= 15V, V
IN
SI
supply current is the current drawn when the BIAS pin is held
+ (I
SB
SB
BIAS
)
)(V
= 5V, I
BIAS
/V
IN
SI
)(1.15)
= 0.55mA, I
C
swing equal to 200mV above the
IN
pin.
SB
A
, T
= 1.6mA and I
SI
CONDITIONS
V
5V V
I
I
I
V
V
V
V
V
Device Starting Up
J
SW
SW
SW
) with a fraction of BIAS
C
BIAS
BIAS
SHDN
C
C
f = 10kHz
= 25 C, V
Set to Give 50% Duty Cycle
Open
Open Device Shutting Down
= 0.5A
= 1.5A
= 5V
= 5V
1.5A
IN
= 0V, V
IN
25V
IN
TOT
and BIAS
IN
= 15V, V
= 1.16mA.
25V, V
The
C
SW
denotes specifications which apply over the full operating temperature
= 1.5V, Boost = V
= 0V, V
Note 7: Switch on resistance is calculated by dividing V
by the forced current (1.5A). See Typical Performance Characteristics for
the graph of switch voltage at other currents.
Note 8: Transconductance and voltage gain refer to the internal amplifier
exclusive of the voltage divider. To calculate gain and transconductance,
refer to the SENSE pin on the fixed voltage parts. Divide values shown by
the ratio V
Note 9: Slope compensation is the current subtracted from the switch
current limit at 80% duty cycle. See Maximum Output Load Current in the
Applications Information section for further details.
Note 10: Minimum on-time is 400ns typical. For a 200kHz operating
frequency this means the minimum duty cycle is 8%. In frequency
foldback mode, the effective duty cycle will be less than 8%.
C
Open
OUT
IN
/1.21.
+ 5V, switch open, unless otherwise noted.
LT1576/LT1576-5
MIN
2.34
0.13
0.25
180
160
250
0.4
0.74
0.55
2.42
0.37
0.45
TYP
200
5.0
2.3
1.6
1.5
27
20
40
8
0
9
IN
MAX
0.15
2.50
0.60
220
240
400
1.0
5.5
3.0
0.8
2.2
0.7
2.2
18
50
50
75
to V
SW
voltage
UNITS
3
%/ V
kHz
kHz
kHz
mA
mA
mA
mA
k
%
V
V
V
A
A
V
V
V
V