LT3042_15 Datasheet, PDF (1/30 Pages) Linear Technology – 20V, 200mA, Ultralow Noise, Ultrahigh PSRR RF Linear Regulator

LT3042
20V, 200mA, Ultralow Noise,
Ultrahigh PSRR RF Linear Regulator
FEATURES
DESCRIPTION
n _{Ultralow RMS Noise: 0.8µVRMS (10Hz to 100kHz)}
n _{Ultralow Spot Noise: 2nV/√Hz at 10kHz}
n _{Ultrahigh PSRR: 79dB at 1MHz}
n _{Output Current: 200mA}
n _{Wide Input Voltage Range: 1.8V to 20V}
n _{Single Capacitor Improves Noise and PSRR}
n _{100µA SET Pin Current: ±1% Initial Accuracy}
n _{Single Resistor Programs Output Voltage}
n _{High Bandwidth: 1MHz}
n _{Programmable Current Limit}
n _{Low Dropout Voltage: 350mV}
n _{Output Voltage Range: 0V to 15V}
n _{Programmable Power Good}
n _{Fast Start-Up Capability}
n _{Precision Enable/UVLO}
n _{Parallelable for Lower Noise and Higher Current}
n _{Internal Current Limit with Foldback}
n _{Minimum Output Capacitor: 4.7µF Ceramic}
n _{Reverse Battery and Reverse Current Protection}
n _{10-Lead MSOP and 3mm × 3mm DFN Packages}
APPLICATIONS
n _{RF Power Supplies: PLLs, VCOs, Mixers, LNAs}
n _{Very Low Noise Instrumentation}
n _{High Speed/High Precision Data Converters}
n _{Medical Applications: Imaging, Diagnostics}
n _{Precision Power Supplies}
n _{Post-Regulator for Switching Supplies}
The LT^®3042 is a high performance low dropout linear
regulator featuring LTC’s ultralow noise and ultrahigh PSRR
architecture for powering noise sensitive RF applications.
Designed as a precision current reference followed by a
high performance voltage buffer, the LT3042 can be easily
paralleled to further reduce noise, increase output current
and spread heat on the PCB.
The device supplies 200mA at a typical 350mV dropout
voltage. Operating quiescent current is nominally 2mA
and drops to <<1µA in shutdown. The LT3042’s wide
output voltage range (0V to 15V) while maintaining unity-
gain operation provides virtually constant output noise,
PSRR, bandwidth and load regulation, independent of the
programmed output voltage. Additionally, the regulator
features programmable current limit, fast start-up capa-
bility and programmable power good to indicate output
voltage regulation.
The LT3042 is stable with a minimum 4.7µF ceramic output
capacitor. Built-in protection includes reverse battery
protection, reverse current protection, internal current
limit with foldback and thermal limit with hysteresis. The
LT3042 is available in thermally enhanced 10-Lead MSOP
and 3mm × 3mm DFN packages.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. Patents Pending. All other trademarks are the property of their
respective owners.
TYPICAL APPLICATION
V_IN
5V ±5%
4.7µF
200k
IN
LT3042
EN/UV
PG
100µA
–
+
SET
GND ILIM
OUT
OUTS
PGFB
4.7µF 33.2k
499Ω
4.7µF
V_OUT
3.3V
I_OUT(MAX)
200mA
450k
50k
3042 TA01a
For more information www.linear.com/LT3042
Power Supply Ripple Rejection
120
110
100
90
80
70
60
50 V_IN = 5V
40
R_SET = 33.2kΩ
C_SET = 4.7µF
30 ^COUT ^{= 4.7µF}
I_L = 200mA
20
10 100 1k
10k 100k
FREQUENCY (Hz)
1M 10M
3042 TA01b
3042fa
1