LTC1261CS8 Linear Technology, LTC1261CS8 Datasheet - Page 11

• Manufacturer Part Number: LTC1261CS8
• Description: IC VOLT INVERT SW-CAP ADJ 8-SOIC
• Manufacturer: Linear Technology
• Type: Switched Capacitor (Charge Pump), Invertingr

Specifications of LTC1261CS8

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: -1.25 ~ -8 V
• Current - Output: 15mA
• Frequency - Switching: 550kHz
• Voltage - Input: 3 ~ 8 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Output Voltage: -1.25 to -8V
• Output Current: 15mA
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 8V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Package Type: SOIC N
• Pin Count: 8
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Not Compliant

APPLICATIONS
Table 2. Output Voltages Using the Internal Resistor Divider
PIN CONNECTIONS
ADJ to R
ADJ to R
ADJ to R
ADJ to R
ADJ to R1
ADJ to R0
ADJ to GND
There are some oddball output voltages available by
connecting ADJ to R0 or R1 and shorting out some of the
internal resistors. If one of these combinations gives you
the output voltage you want, by all means use it!
The internal resistor values are the same for the fixed
output versions of the LTC1261 as they are for the adjust-
TYPICAL APPLICATIONS
ADJ
ADJ
ADJ
ADJ
, R0 to GND
, R1 to R0
, R1 to GND
U
INFORMATION
U
SHUTDOWN
0.1 F
0.1 F
V
3.3V
BAT
U
NC
OUTPUT VOLTAGE
W
3.3V Input, – 4.5V Output GaAs FET Bias Generator
2
3
4
5
8
– 1.77V
– 1.38V
– 1.24V
– 3.5V
– 4.5V
N
– 5V
– 4V
1 F
C1
C1
C2
C2
R1
R0
–
+
+
–
LTC1261
7
V
CC
14
GND
SHDN
U
R
REG
OUT
ADJ
ADJ
6
13
12
11
10
9
100pF
able. The output voltage can be trimmed, if desired, by
connecting external resistance from the COMP pin to OUT
or ground to alter the divider ratio. As in the adjustable
parts, the absolute value of the internal resistors may vary
significantly from unit to unit. As a result, the further the
trim shifts the output voltage the less accurate the output
voltage will be. If a precise output voltage other than one
of the available fixed voltages is required, it is better to use
an adjustable LTC1261 and use precision external resis-
tors. The internal reference is trimmed at the factory to
within 3.5% of 1.24V; with 1% external resistors the
output will be within 5.5% of the nominal value, even
under worst case conditions.
The LTC1261 can be internally configured with nonstand-
ard fixed output voltages. Contact the Linear Technology
Marketing Department for details.
+
10k
POWER SWITCH
3.3 F
P-CHANNEL
–4.5V BIAS
TRANSMITTER
GaAs
LTC1261 • TA03
LTC1261
11