LTC1261LCS8-4#PBF Linear Technology, LTC1261LCS8-4#PBF Datasheet

IC SW CAP/INV -4V 20MA 8SOIC

LTC1261LCS8-4#PBF

Manufacturer Part Number
LTC1261LCS8-4#PBF
Description
IC SW CAP/INV -4V 20MA 8SOIC
Manufacturer
Linear Technology
Type
Switched Capacitor (Charge Pump), Invertingr
Datasheet

Specifications of LTC1261LCS8-4#PBF

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
-4V
Current - Output
20mA
Frequency - Switching
650kHz
Voltage - Input
4V
Operating Temperature
0°C ~ 70°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LTC1261LCS8-4#PBFLTC1261LCS8-4
Manufacturer:
LT
Quantity:
10 000
Company:
Part Number:
LTC1261LCS8-4#PBFLTC1261LCS8-4.5
Manufacturer:
LT
Quantity:
10 000
FEATURES
TYPICAL
APPLICATIO S
1 F
Regulated Negative Voltage from a
Single Positive Supply
REG Pin Indicates Output is in Regulation
Adjustable or Fixed Output Voltages
Output Regulation: 3.5%
Supply Current: 650 A Typ
Shutdown Mode Drops Supply Current to 5 A
Up to 20mA Output Current
Requires Only Three or Four External Capacitors
Available in MS8 and SO-8 Packages
GaAs FET Bias Generators
Negative Supply Generators
Battery-Powered Systems
Single Supply Applications
5V
C1
0.1 F
C2
APPLICATION
– 4V Generator with Power Valid
1
2
3
4
U
V
C1
C1
GND
CC
LTC1261L-4
+
COMP
SHDN
REG
OUT
8
7
6
5
U
5V
10k
C3*
100pF
*OPTIONAL
+
POWER VALID
C4
3.3 F
V
AT 10mA
OUT
1261L TA01
= –4V
Regulated Voltage Inverter
DESCRIPTIO
The LTC
designed to provide a regulated negative voltage from a
single positive supply. The LTC1261L operates from a
single 2.7V to 5.25V supply and provides an adjustable
output voltage from –1.23V to – 5V. The LTC1261L-4/
LTC1261L-4.5 needs a single 4.5V to 5.25V supply and
provides a fixed output voltage of – 4V to – 4.5V respec-
tively. Three external capacitors are required: a 0.1 F
flying capacitor and an input and output bypass capaci-
tors. An optional compensation capacitor at ADJ (COMP)
can be used to reduce the output voltage ripple.
Each version of the LTC1261L will supply up to 20mA
output current with guaranteed output regulation of 3.5%.
The LTC1261L includes an open-drain REG output that
pulls low when the output is within 5% of the set value.
Quiescent current is typically 650 A when operating and
5 A in shutdown.
The LTC1261L is available in 8-pin MSOP and SO pack-
ages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
POWER VALID
SHDN
®
OUT
1261L is a switched-capacitor voltage inverter
– 4V
Waveforms for – 4V Generator with Power Valid
0V
5V
0V
5V
0V
Switched Capacitor
U
0.1ms/DIV
LTC1261L
1261L TAO2
1

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LTC1261LCS8-4#PBF Summary of contents

Page 1

... The LTC1261L includes an open-drain REG output that pulls low when the output is within 5% of the set value. Quiescent current is typically 650 A when operating and shutdown. The LTC1261L is available in 8-pin MSOP and SO pack- ages. , LTC and LT are registered trademarks of Linear Technology Corporation. 5V 10k POWER VALID SHDN V = – ...

Page 2

... Consult factory for Industrial or Military grade parts or additional fixed voltage parts. ELECTRICAL C HARA TERISTICS C temperature range, otherwise specifications are at T SYMBOL PARAMETER V Supply Voltage CC (LTC1261LCMS8/LTC1261LCS8) (LTC1261LCMS8-4/LTC1261LCS8-4) (LTC1261LCMS8-4.5/LTC1261LCS8-4.5) (Note 5) V Reference Voltage REF I Supply Current CC f Internal Oscillator Frequency OSC V REG Output Low Voltage ...

Page 3

ELECTRICAL C HARA TERISTICS C temperature range, otherwise specifications are at T SYMBOL PARAMETER V Output Regulation (LTC1261L) OUT Output Regulation (LTC1261L/LTC1261L-4) Output Regulation (LTC1261L/LTC1261L-4.5) I Output Short-Circuit Current SC Note 1: The Absolute Maximum Ratings are those values beyond ...

Page 4

LTC1261L W U TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage vs Supply Voltage – 3. – 4V OUT – 3.90 – 3. – – 4. ...

Page 5

PIN FUNCTIONS V (Pin 1): Power Supply. This requires an input voltage CC between 2.7V and 5.25V. V must be bypassed to CC ground with at least capacitor placed in close proximity to the ...

Page 6

LTC1261L U U APPLICATIONS INFORMATION The LTC1261L uses an inverting charge pump to generate a regulated negative output voltage that is either equal to or less than the supply voltage. The LTC1261L needs only three external capacitors and is available ...

Page 7

U U APPLICATIONS INFORMATION COMP2 also monitors the divided signal at ADJ but it is connected to a 1.17V reference, 5% below the main reference voltage. When the divided output exceeds this lower reference voltage indicating that the output is ...

Page 8

LTC1261L U U APPLICATIONS INFORMATION OUTPUT FILTERING If extremely low output ripple (< 5mV) is required, addi- tional output filtering is required. Because the LTC1261L uses a high 650kHz switching frequency, fairly low value networks can be ...

Page 9

... If the initial output is not what AVERAGE you expected, try swapping the two resistors. COMP1 OUTPUT The LTC1261L can be internally configured for other V SET fixed output voltages. Contact the Linear Technology V OUT Marketing department for details. AVERAGE COMP1 OUTPUT 1261L F04 ...

Page 10

LTC1261L U TYPICAL APPLICATIONS SHUTDOWN 0.1 F 1mV Ripple, 5V Input, – 4V Output GaAs FET Bias Generator V SHUTDOWN 0 BAT SHUTDOWN 0 Input, ...

Page 11

... FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 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. ...

Page 12

... Input, 5-lead SOT-23 –5V at 200mA from 5V Input in MSOP –15V at 12mA from 2.5V Input, 5-lead SOT-23 Output Noise = 2.5V to 5.5V Output RMS = 50mA (V 3V 25mA CC OUT IN OUT (V 2.7V) IN 1261lf LT/TP 0200 4K • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1999 = – 4.5V 1261L TA07 up to 50mA ...

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