TPS79401 Datasheet, PDF (1/15 Pages) Texas Instruments – ULTRALOW-NOISE, HIGH PSRR, FAST RF 250-mA LOW-DROPOUT LINEAR REGULATORS

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TPS79401, TPS79418
TPS79425, TPS79428
TPS79430, TPS79433
SLVS349D – NOVEMBER 2001 – REVISED OCTOBER 2004
ULTRALOW-NOISE, HIGH PSRR, FAST RF 250-mA LOW-DROPOUT LINEAR
REGULATORS
FEATURES
• 250-mA Low-Dropout Regulator With Enable
• Available in 1.8 V, 2.5 V, 2.8 V, 3 V, 3.3 V, and
Adjustable (1.2 V to 5.5 V)
• High PSRR (60 dB at 10 kHz)
• Ultralow Noise (32 µVrms, TPS79428)
• Fast Start-Up Time (50 µs)
• Stable With a 2.2-µF Ceramic Capacitor
• Excellent Load/Line Transient Response
• Very Low Dropout Voltage (155 mV at Full
Load)
• Available in MSOP-8 and SOT223-6 Packages
APPLICATIONS
• RF: VCOs, Receivers, ADCs
• Audio
• Bluetooth™, Wireless LAN
• Cellular and Cordless Telephones
• Handheld Organizers, PDAs
DESCRIPTION
The TPS794xx family of low-dropout (LDO) linear
voltage regulators features high power-supply rejec-
tion ratio (PSRR), ultralow-noise, fast start-up, and
excellent line and load transient responses in small
outline, MSOP-8 PowerPAD™ and SOT223-6 pack-
ages. Each device in the family is stable with a small
2.2-µF ceramic capacitor on the output. The family
uses an advanced, proprietary BiCMOS fabrication
process to yield extremely low dropout voltages (e.g.,
155 mV at 250 mA). Each device achieves fast
start-up times (approximately 50 µs with a 0.001-µF
bypass capacitor) while consuming low quiescent
current (170 µA typical). Moreover, when the device
is placed in standby mode, the supply current is
reduced to less than 1 µA. The TPS79428 exhibits
approximately 32 µV_RMS of output voltage noise at
2.8 V output with a 0.1-µF bypass capacitor. Appli-
cations with analog components that are
noise-sensitive, such as portable RF electronics,
benefit from the high PSRR and low noise features as
well as the fast response time.
DGN PACKAGE
MSOP PowerPAD
(TOP VIEW)
OUT
1
NC
2
FB
3
NR
4
8
IN
7
NC
6
EN
5
GND
NC − No internal connection
EN
IN
GND
OUT
NR
DCQ PACKAGE
SOT223-6
(TOP VIEW)
1
2
3
6
GND
4
5
TPS79433
RIPPLE REJECTION
vs
FREQUENCY
90
80
I_OUT = 10 mA
70
I_OUT = 250 mA
60
50
40
30
V_IN = 4.3 V,
20
V_OUT = 3.3 V,
C_IN = 1 µF,
10
C_OUT = 10 µF,
C_NR = 0.01 µF
0
10 100 1 k 10 k 100 k 1 M 10 M
Frequency (Hz)
TPS79428
OUTPUT SPECTRAL NOISE DENSITY
vs
FREQUENCY
0.35
0.30
C_OUT = 2.2 µF,
C_NR = 0.1 µF,
V_IN = 3.8 V
0.25
0.20
I_OUT = 250 mA
0.15
0.10
0.05
0
100
I_OUT = 1 mA
1000
10000
Frequency (Hz)
100000
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Bluetooth is a trademark of Bluetooth SIG, Inc.
PowerPAD is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2001–2004, Texas Instruments Incorporated