Datasheet

LTC3421
2
3421f
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum V
IN
Start-Up Voltage I
LOAD
< 1mA 0.88 1 V
Minimum V
IN
Operating Voltage (Note 4) ● 0.5 V
Output Voltage Adjust Range 2.25 5.25 V
● 2.40 5.25 V
Feedback Voltage ● 1.196 1.220 1.244 V
Feedback Input Current V
FB
= 1.22V 1 50 nA
Quiescent Current—Burst Mode Operation V
C
= 0V, ENB = 0V (Note 3) 12 20 µA
V
C
= 0V, ENB = 2V (Note 3) 23 50 µA
Quiescent Current—Shutdown SHDN = 0V, ENB = 0V 0.1 1 µA
SHDN = 0V, ENB > 1.4V 0.2 2 µA
Quiescent Current—Active (Note 3) 0.6 1.1 mA
NMOS Switch Leakage 0.1 5 µA
PMOS Switch Leakage 0.1 10 µA
NMOS Switch On Resistance 0.1 Ω
PMOS Switch On Resistance 0.14 Ω
NMOS Current Limit I
LIM
Resistor = 105k ● 1 1.5 A
I
LIM
Resistor = 36.5k ● 3 4.2 A
Max Duty Cycle ● 84 91 %
Min Duty Cycle ● 0%
V
IN
, V
OUT
, V
OUTS
Voltage ............................ –0.3V to 6V
BURST, SHDN, SS, ENB, SW,
LBO, LBI, SYNC Voltages .......................... –0.3V to 6V
Operating Temperature Range
(Notes 2, 5)............................................. –40°C to 85°C
Storage Temperature Range ................. –65°C to 125°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART NUMBER
Consult LTC Marketing for parts specified with wider operating temperature ranges.
LTC3421EUF
ABSOLUTE AXI U RATI GS
W
WW
U
PACKAGE/ORDER I FOR ATIO
UUW
(Note 1)
T
JMAX
= 125°C, θ
JA
= 40°C/W 1 LAYER BOARD,
θ
JA
= 35°C/W 4 LAYER BOARD, θ
JC
= 2.6°C/W
EXPOSED PAD IS GND (PIN 25) MUST BE SOLDERED TO PCB
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 1.2V, V
OUT
= 3.3V, R
T
= 28k, unless otherwise noted.
24 23 22 21 20 19
7 8 9
TOP VIEW
25
UF PACKAGE
24-LEAD (4mm × 4mm) PLASTIC QFN
10 11 12
6
5
4
3
2
1
13
14
15
16
17
18
FB
SHDN
V
REF
ENB
R
T
SS
V
OUTS
V
OUT
SW
SW
SW
PGND
V
C
LBI LBO V
IN
V
OUT
V
OUT
SYNC
I
LIM
BURST
GND
PGND PGND
UF PART MARKING 3421