Datasheet

MAX1875/MAX1876
Dual 180° Out-of-Phase PWM Step-
Down Controllers with POR
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 12V, EN = ILIM_ = V
L
, SYNC = GND, I
VL
= 0mA, PGND = GND, C
REF
= 0.22µF, C
VL
= 4.7µF (ceramic), R
OSC
= 60kΩ,
compensation components for COMP_ are from Figure 1, T
A
= -40°C to +85°C (Note 1), unless otherwise noted.)
PARAMETER CONDITIONS
MIN TYP MAX UNITS
SYNC Range
Internal oscillator nominal frequency must be set to half
of the SYNC frequency
200 1200
kHz
High
100
SYNC Input Pulse Width (Note 3)
Low
100
ns
SYNC Rise/Fall Time (Note 3) 100 ns
ERROR AMPLIFIER
FB_ Input Bias Current 250 nA
0°C to +85°C
0.985 1.00 1.015
FB_ Input Voltage Set Point
-40°C to +85°C
0.98 1.00 1.02
V
0°C to +85°C
1.25
1.8
2.70
FB_ to COMP_ Transconductance
-40°C to +85°C 1.2 1.8 2.9
mS
DRIVERS
DL_, DH_ Break-Before-Make Time
C
LOAD
= 5nF 30 ns
Low 1.5 2.5
DH_ On-Resistance
High 3 5
Ω
Low 0.6 1.5
DL_ On-Resistance
High 3 5
Ω
LOGIC INPUTS (EN, SYNC)
Input Low Level Typical 15% hysteresis, V
L
= 4.75V 0.8 V
Input High Level V
L
= 5.5V 2.4 V
Input High/Low Bias Current V
EN
= 0 or 5.5V -1 0.1 +1 µA
LOGIC OUTPUTS (CKO)
Output Low Level V
L
= 5V, sinking 5mA 0.4 V
Output High Level V
L
= 5V, sourcing 5mA 4.0 V
COMP_
Pulldown Resistance During
Shutdown and Current Limit
17 Ω
RST OUTPUT (MAX1876 ONLY)
Output-Voltage Trip Level
Both FBs must be over this to allow the reset timer to
start; there is no hysteresis
0.87
0.9
0.93
V
V
L
= 5V, sinking 3.2mA 0.4
Output Low Level
V
L
= 1V, sinking 0.4mA 0.3
V
Output Leakage V+ = V
L
= 5V, V
RST
= 5.5V, V
FB
= 1V 1 µA
Reset Timeout Period V
FB_
= 1V
140 315
560 ms
FB_ to Reset Delay FB_ overdrive from 1V to 0.85V 4 µs
Note 1: Specifications to -40°C are guaranteed by design and not production tested.
Note 2: Operating supply range is guaranteed by V
L
line regulation test. Connect V+ to V
L
for 5V operation.
Note 3: Guaranteed by design and not production tested.