LTC3265
Low Noise Dual Supply
with Boost and Inverting
Charge Pumps
FEATURES DESCRIPTION
n
Boost Charge Pump Generates 2 V The LTC 3265 is a low noise dual polarity output power
IN_P
(V Range: 4.5V to 16V) supply including a boost charge pump, an inverting charge
IN_P
n
pump and two low noise positive and negative LDO post
Inverting Charge Pump Generates V
IN_N
regulators. The boost charge pump powers the positive
(V Range: 4.5V to 32V)
IN_N
n LDO post regulator while the inverting charge pump pow-
Low Noise Positive LDO Post Regulator Up to 50mA
n ers the negative LDO regulator. Each LDO can provide up
Low Noise Negative LDO Post Regulator Up to 50mA
n to 50mA of output current. The LDO output voltages can
135A Quiescent Current in Burst Mode Operation
be adjusted using external resistor dividers.
with Both LDO Regulators On
n
50kHz to 500kHz Programmable Oscillator Frequency
The charge pumps employ low quiescent current
n
Stable with Ceramic Capacitors
BurstMode operation or low noise constant frequency
n
Short-Circuit/Thermal Protection
mode. During Burst Mode operation, the boost charge
n +
Low Profile 3mm 5mm 18-Lead DFN and Thermally
pump regulates its output (V ) to 0.94 2 V while
OUT IN_P
Enhanced 20-Lead TSSOP Packages
the inverting charge pump regulates its output (V )
OUT
to 0.94 V . In Burst Mode operation the LTC3265
IN_N
draws only 135A of quiescent current with both LDOs
APPLICATIONS
on. In constant frequency mode, the boost and inverting
n charge pumps produce outputs equal to 2 V and
Low Noise Bipolar/Inverting Supplies IN_P
V respectively and operate at a fixed 500kHz or to
n
IN_N
Industrial/Instrumentation Low Noise Bias Generators
a programmed value between 50kHz to 500kHz using an
external resistor. The LTC3265 is available in low profile
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
3mm 5mm 0.75mm 18-lead DFN and thermally
property of their respective owners.
enhanced 20-lead TSSOP packages.
TYPICAL APPLICATION
Low Noise 15V Outputs from a Single 12V Input LDO Rejection of V Ripple
OUT
1F
+
V
OUT
10mV/DIV
AC-COUPLED
+
CBST CBST
+
V
+
LDO
V V
IN_N OUT
10mV/DIV
10F
AC-COUPLED
+ V
+15V LDO
12V V LDO
IN_P
10mV/DIV
10F 10F
LTC3265 AC-COUPLED
604K
+ +
V
EN ADJ
OUT
+
10mV/DIV
EN BYP
52.3k
100nF AC-COUPLED
MODE GND 3265 TA01b
1s/DIV
100nF
+ +
CINV BYP V = 12V, V = V
IN_P IN_N OUT
52.3k +
1F
V = 15V
LDO
CINV ADJ
V = 15V
LDO
f = 500kHz
604K
OSC
+
I = 20mA
LDO
V LDO 15V
OUT
I = 20mA
LDO
10F
10F
RT
3265 TA01a
3265fa
1
For more information www.linear.com/LTC3265LTC3265
ABSOLUTE MAXIMUM RATINGS (Notes 1, 3)
+
V , EN , EN , MODE .............................. 0.3V to 18V BYP ......................................................... 2.5V to 0.3V
IN_P
+
V , V .............................................. 0.3V to 36V LDO Short-Circuit Duration ............................ Indefinite
OUT IN_N
+
LDO ............................................................16V to 36V Operating Junction Temperature Range
V , LDO ............................................... 36V to 0.3V (Note 2) .................................................. 55C to 150C
OUT
+
RT, ADJ ...................................................... 0.3V to 6V Storage Temperature Range .................. 65C to 150C
+
BYP ......................................................... 0.3V to 2.5V Lead Temperature (Soldering, 10 sec)
ADJ ............................................................ 6V to 0.3V FE Only .............................................................300C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
+
NC 1 20 V
OUT
+ +
CBST 1 18 V CBST 2 19 LDO
OUT
+ +
+ +
CBST 2 17 LDO
CBST 3 18 ADJ
+
V 3 16 ADJ +
IN_P
VIN_P 4 17 BYP
+
EN 4 15 BYP
EN 5 16 MODE
19 21
BYP 5 14 MODE
GND GND +
BYP 6 15 EN
+
ADJ 6 13 EN
ADJ 7 14 RT
LDO 7 12 RT
LDO 8 13 V
V 8 11 V
IN_N
OUT IN_N
+ +
CINV 9 10 CINV V 9 12 CINV
OUT
CINV 10 11 NC
DHC PACKAGE
18-LEAD (5mm 3mm) PLASTIC DFN
FE PACKAGE
T = 150C, = 42C/W
20-LEAD PLASTIC TSSOP
JMAX JA
EXPOSED PAD (PIN 19) IS GND, MUST BE SOLDERED TO PCB
T = 150C, = 38C/W
JMAX JA
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
(