LT1121CS8-5#PBF Linear Technology, LT1121CS8-5#PBF Datasheet - Page 12

• Manufacturer Part Number: LT1121CS8-5#PBF
• Description: IC REG LDO 5V 150MA 8-SOIC
• Manufacturer: Linear Technology

Specifications of LT1121CS8-5#PBF

• Regulator Topology: Positive Fixed
• Voltage - Output: 5V
• Voltage - Input: Up to 30V
• Voltage - Dropout (typical): 0.42V @ 150mA
• Number Of Regulators: 1
• Current - Output: 150mA
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Primary Input Voltage: 30V
• Output Voltage Fixed: 5V
• Dropout Voltage Vdo: 420mV
• No. Of Pins: 8
• Output Current: 150mA
• Operating Temperature Range: 0°C To +125°C
• Msl: MSL 1 - Unlimited
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Limit (min): -

APPLICATIO S I FOR ATIO
LTC1608
The best choice for an op amp to drive the LTC1608 will
depend on the application. Generally applications fall into
two categories: AC applications where dynamic specifi-
cations are most critical and time domain applications
where DC accuracy and settling time are most critical.
The following list is a summary of the op amps that are
suitable for driving the LTC1608. More detailed informa-
tion is available in the Linear Technology databooks, the
LinearView
www.linear-tech. com.
LT
current, 5V to 15V supplies, gain bandwidth product
8MHz, DC applications.
LT1097: Low Cost, Low Power Precision Amplifier. 300 A
supply current, 5V to 15V supplies, gain bandwidth
product 0.7MHz, DC applications.
LT1227: 140MHz Video Current Feedback Amplifier. 10mA
supply current, 5V to 15V supplies, low noise and low
distortion.
LT1360: 37MHz Voltage Feedback Amplifier. 3.8mA sup-
ply current, 5V to 15V supplies, good AC/DC specs.
LT1363: 50MHz Voltage Feedback Amplifier. 6.3mA sup-
ply current, good AC/DC specs.
LT1364/LT1365: Dual and Quad 50MHz Voltage Feedback
Amplifiers. 6.3mA supply current per amplifier, good
AC/DC specs.
LT1468: 90MHz, 22V/ s 16-Bit Accurate Operational
Amplifier. 3.8mA supply current, excellent DC specs and
very low distortion performance to 100kHz.
LT1469: Dual 90MHz, 22V/ s 16-Bit Accurate Operational
Amplifier. 4.1mA supply current, excellent DC specs and
very low distortion performance to 100kHz.
Input Filtering
The noise and the distortion of the input amplifier and
other circuitry must be considered since they will add to
the LTC1608 noise and distortion. The small-signal band-
width of the sample-and-hold circuit is 15MHz. Any noise
or distortion products that are present at the analog inputs
will be summed over this entire bandwidth. Noisy input
circuitry should be filtered prior to the analog inputs to
12
®
1007: Low Noise Precision Amplifier. 2.7mA supply
TM
CD-ROM and on our web site at:
U
U
W
U
minimize noise. A simple 1-pole RC filter is sufficient for
many applications. For example, Figure 11 shows a 3000pF
capacitor from A
to limit the input bandwidth to 530kHz. The 3000pF
capacitor also acts as a charge reservoir for the input
sample-and-hold and isolates the ADC input from sam-
pling glitch sensitive circuitry. High quality capacitors and
resistors should be used since these components can add
distortion. NPO and silver mica type dielectric capacitors
have excellent linearity. Carbon surface mount resistors can
also generate distortion from self heating and from damage
that may occur during soldering. Metal film surface mount
resistors are much less susceptible to both problems.
Input Range
The 2.5V input range of the LTC1608 is optimized for low
noise and low distortion. Most op amps also perform well
over this same range, allowing direct coupling to the
analog inputs and eliminating the need for special transla-
tion circuitry.
Some applications may require other input ranges. The
LTC1608 differential inputs and reference circuitry can ac-
commodate other input ranges often with little or no addi-
tional circuitry. The following sections describe the refer-
ence and input circuitry and how they affect the input range.
Internal Reference
The LTC1608 has an on-chip, temperature compensated,
curvature corrected, bandgap reference that is factory
trimmed to 2.500V. It is connected internally to a reference
amplifier and is available at V
LinearView is a trademark of Linear Technology Corporation.
ANALOG INPUT
IN
Figure 11. RC Input Filter
3000pF
+
100
22 F
to ground and a 100 source resistor
REF
1
2
3
4
5
(Pin 3) (see Figure 12a).
A
A
V
REFCOMP
AGND
IN
IN
REF
+
–
LTC1608
1608 F11