Datasheet

MAX1809
3A, 1MHz, DDR Memory Termination Supply
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= V
CC
= 3.3V, V
EXTREF
= 1.1V, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note 1: LX has clamp diodes to PGND and IN. If continuous current is applied through these diodes, thermal limits must be
observed.
V
CC
, IN to GND ........................................................-0.3V to +6V
IN to V
CC
.............................................................................±0.3V
GND to PGND.....................................................................±0.3V
SHDN, SS, FB, T
OFF
, R
REF
,
EXTREF to GND.......................................-0.3V to (V
CC
+ 0.3V)
LX Current (Note 1).............................................................±4.7A
REF Short Circuit to GND Duration ............................Continuous
Continuous Power Dissipation (T
A
= +70°C)
28-Pin QFN (derate 20mW/°C above +70°C;
part mounted on 1in
2
of 1oz copper)..............................1.6W
16-Pin QSOP (derate 12.5mW/°C above +70°C;
part mounted on 1in
2
of 1oz copper).................................1W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Voltage V
IN
,V
CC
3.0 5.5 V
Feedback Voltage Accuracy
(V
FB
- V
EXTREF
)
V
IN
= V
CC
= 3V to 5.5V, I
LOAD
= 0,
V
EXTREF
= 1.25V (Note 2)
-12 +12 mV
Feedback Load Regulation Error ∆V
FB
I
LOAD
= -3A to +3A, V
EXTREF
= 1.25V 20 mV
External Reference Voltage
Range
V
EXTREF
V
IN
= V
CC
= 3V to 5.5V
V
REF
-
0.01
V
IN
-
1.7
V
Reference Voltage V
REF
1.078 1.100 1.122 V
Reference Load Regulation I
REF
= -1µA to +10µA 0.5 2.0 mV
V
IN
= 4.5V 90 200
PMOS Switch
On-Resistance
R
PMOS
I
LX
= 0.5A
V
IN
= 3V 110 250
mΩ
V
IN
= 4.5V 70 150
NMOS Switch
On-Resistance
R
NMOS
I
LX
= 0.5A
V
IN
= 3V 80 200
mΩ
Current-Limit Threshold I
LIMIT
V
IN
> V
LX
3.5 4.1 4.7 A
Switching Frequency f
SW
(Note 3) 1 MHz
I
CC
f
SW
= 500kHz 1
No Load Supply Current
I
IN
f
SW
= 500kHz 16
mA
Shutdown Supply Current I
SHDN
SHDN = GND, I
CC
+ I
IN
<1 15 µA
Thermal-Shutdown Threshold Hysteresis = 15°C 160 °C
Undervoltage Lockout Threshold V
CC
falling, hysteresis = 90mV 2.5 2.6 2.7 V
FB Input Bias Current I
FB
V
FB
= V
EXTREF
+ 0.1V 0 60 250 nA
R
TOFF
= 30.1kΩ 0.24 0.30 0.37
R
TOFF
= 110kΩ 0.9 1.0 1.1
Off-Time t
OFF
R
TOFF
= 499kΩ 3.8 4.5 5.2
µs
Startup Off-Time 4 x t
OFF
µs
On-Time t
ON
(Note 3) 0.35 µs