LT1073CS8 Linear Technology, LT1073CS8 Datasheet - Page 4

• Manufacturer Part Number: LT1073CS8
• Description: IC DC/DC CONVERTER ADJSTBL 8SOIC
• Manufacturer: Linear Technology
• Type: Step-Down (Buck), Step-Up (Boost), Invertingr

Specifications of LT1073CS8

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: Adjustable
• Current - Output: 400mA
• Frequency - Switching: 19kHz
• Voltage - Input: 1 ~ 30 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Power - Output: 500mW
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

BLOCK DIAGRA S
LT1073
I
lower current limit is desired, connect a resistor between
I
to approximately 400mA.
V
SW1 (Pin 3): Collector of Power Transistor. For step-up
mode connect to inductor/diode. For step-down mode
connect to V
SW2 (Pin 4): Emitter of Power Transistor. For step-up
mode connect to ground. For step-down mode connect to
inductor/diode. This pin must never be allowed to go more
than a Schottky diode drop below ground.
TYPICAL PERFOR A CE CHARACTERISTICS
PI FU CTIO S
4
LIM
LIM
IN
U
150
140
130
120
110
100
(Pin 2): Input Supply Voltage
REFERENCE
(Pin 1): Connect this pin to V
and V
90
80
70
60
50
212mV
–50
GND
Supply Current vs Temperature
V
IN
V
IN
–25
IN
= 1.5V
U
SET
. A 220 resistor will limit the switch current
IN
FB
.
0
TEMPERATURE ( C)
+
–
25
GAIN BLOCK/ERROR AMP
U
A2
A1
COMPARATOR
50
LT1073
W
75
W
A0
100
OSCILLATOR
IN
1073 G07
U
for normal use. Where
125
DRIVER
300
250
200
150
100
I
LIM
50
0
1.0
Recommended Minimum
Inductance Value
R
LIM
1073 BD01
SW1
SW2
1.5
= 0V
Q1
2.0
INPUT VOLTAGE (V)
2.5
3.0
GND (Pin 5): Ground.
AO (Pin 6): Auxiliary Gain Block (GB) Output. Open collec-
tor, can sink 100 A.
SET (Pin 7): GB Input. GB is an op amp with positive input
connected to SET pin and negative input connected to
212mV reference.
FB/SENSE (Pin 8): On the LT1073 (adjustable) this pin
goes to the comparator input. On the LT1073-5 and
LT1073-12, this pin goes to the internal application resis-
tor that sets output voltage.
3.5
REFERENCE
212mV
GND
4.0
V
IN
R1
4.5
SET
1073 G08
5.0
940k
R2
LT1073-5 and LT1073-12
–
+
GAIN BLOCK/ERROR AMP
COMPARATOR
A2
A1
SENSE
1000
100
10
1.0
Guaranteed Minimum Output
Current at 5V vs V
1.5
A0
OSCILLATOR
LT1073-12: R2 = 16.3k
LT1073-5: R1 = 40k
2.0
V
IN
FOR V
68 RESISTOR
MUST BE CONNECTED
BETWEEN I
(V)
IN
2.5
DRIVER
IN
I
LIM
> 1.6V A
LIM
3.0
1073 BD02
AND V
SW1
SW2
Q1
1073 G09
IN
3.5