Datasheet

MAX1917
Tracking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 12V, V
EN/HSD
= V
DDR
= 2.5V, C
VL
= 4.7µF, C
VTTR
= 1µF, C
REF
= 0.22µF, V
FSEL
= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for T
A
= -40°C to +85°C, unless otherwise specified.) (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Reference UVLO V+ = VL = 5V 1.5 1.7 V
VTTR
VTTR Output Voltage Range 0 1.8 V
I
VTTR
= -5mA to +5mA 49.5 50.5
I
VTTR
= -25mA to +25mA, V
DDR
= 1.8V 49 51VTTR Output Accuracy
I
VTTR
= -25mA to +25mA, V
DDR
= 3.6V 49.5 50.5
%V
DDR
OSCILLATOR
FSEL = VL 2.18 2.83
FSEL not connected 1.45 1.89
FSEL = REF 1.09 1.41
On Time (Note 1)
FSEL = GND 0.82 1.00
µs
Minimum Off Time (Note 1) 400 ns
CURRENT LIMIT
LX to PGND, ILIM = VL 85 110
LX to PGND, R
ILIM
= 100kΩ 35 60
Current-Limit Threshold
(Positive Direction)
LX to PGND, R
ILIM
= 400kΩ 160 230
mV
Current-Limit Threshold
(Negative Direction)
LX to PGND, ILIM = VL, with percentage of positive
current-limit threshold
-90 -130 %
VL REGULATOR
Output Voltage 5.5V < V+ < 14V; 1mA < I
VL
< 35mA 4.8 5.2 V
RMS Output Current 35 mA
Bypass Capacitor ESR < 100mΩ 2.2 µF
FSEL LOGIC
Logic Input Current 3µA
Logic GND Level 0.5 V
Logic REF Level FSEL = VREF 1.65 2.35 V
Logic Float Level FSEL floating 3.15 3.85 V
Logic VL Level FSEL = VL VL - 0.4 V
EN/HSD LOGIC
EN/HSD Shutdown Current I
EN/HSD
for V
EN/HSD
= 0.8V 0.5 3.0 µA
Logic High VL = V+ = 4.5V to 5.5V, 100mV hysteresis 1.45 V
Logic Low VL = V+ = 4.5V to 5.5V 0.8 V
POWER-OK OUTPUT
Upper VTT Threshold 110 114
%V
DDR
/2
Lower VTT Threshold 86 90
%V
DDR
/2