LT1306 Datasheet, PDF (1/16 Pages) Linear Technology – Synchronous, Fixed Frequency Step-Up DC/DC Converter

LT1306
Synchronous, Fixed Frequency
Step-Up DC/DC Converter
FEATURES
s _{Output Disconnected from Input During Shutdown}
s _{Output Voltage Remains Regulated}
When V_IN > V_OUT
s _{Controlled Input Current During Start-Up}
s _{300kHz Current Mode PWM Operation}
s _{Can Be Externally Synchronized}
s _{Internal 2A Switches}
s _{Operates with VIN as Low as 1.8V}
s _{Automatic Burst Mode Operation at Light Loads}
s _{Quiescent Current: 160µA}
s _{Shutdown Current: 9µA Typ}
U
APPLICATIO S
s _{Satellite Phones}
s _{Portable Instruments}
s _{Personal Digital Assistants}
s _{Palmtop Computers}
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
DESCRIPTIO
The LT^®1306 is a fully integrated, fixed frequency syn-
chronous boost converter capable of generating 5V at 1A
from a Li-Ion cell. The device contains both the main
power switch and synchronous rectifier on chip and
automatically disconnects the output from the input in
shutdown, eliminating the need for external load discon-
nect circuitry. Additionally, the output remains regulated
when V_IN exceeds V_OUT, allowing difficult step-up/step-
down converter functions to be easily realized using a
single inductor.
The internal 300kHz oscillator of the LT1306 can be easily
synchronized to an external clock from 425kHz to 500kHz.
This allows switching harmonics to be tightly controlled
and eliminates any beat frequencies that may result from
a multifrequency system. The LT1306 automatically shifts
into power saving Burst Mode^TM operation at light loads.
At heavy loads the LT1306 operates in fixed frequency
current mode. No-load quiescent current is 160µA and
reduces to 9µA in shutdown mode.
The LT1306 is available in an SO-8 package.
TYPICAL APPLICATION
1-CELL
Li-Ion
+ _CIN1
22µF
D1
L1
10µH
C1
1µF
V_IN
S/S
C_IN2
0.1µF
V_C
SW
LT1306
CAP
OUT
FB
GND
R3
118k
C_Z
68nF
C_P
68pF
R1
768k
+
R2
249k
C_O1
220µF
1306 F01
Figure 1. Single Li-Ion Cell to 5V Converter
5V
1A
C_O2
1µF
C_IN1: AVX TAJC226M010
C_O1: AVX TPSE227M010R0100
C_IN1, C_O2: CERAMIC
C1: AVX TAJA105K020
D1: MMBD914LT1
L1: CTX10-2
Efficiency
90
85
V_IN = 4.2V
80
V_IN = 3.6V
75
V_IN = 2.6V
70
65 ^VO ^{= 5V}
L1 = 10µH
(FIGURE 1)
60
1
10
100
LOAD CURRENT (mA)
1000
1306 TA01
1