Manual

MAX8775
Dual and Combinable Graphics Core
Controller for Notebook Computers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= 12V, SKIP_ = PGND = AGND, ON_ = V
CC
= 5V, separate mode, T
A
= 0°C to +85°C, unless otherwise
noted. Typical values are at T
A
= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
50 %
SMPS1 to SMPS2 Phase Shift SMPS2 starts after SMPS1
180 Deg
I
SLEW_
During transition 4.0 4.75 5.5
Slew-Rate Current
I
SLEWSS_
Startup and shutdown 0.70 0.95 1.20
µA
CURRENT LIMIT
Current-Limit Threshold V
LIMIT
V
CSH
_ - V
CSL
_ 26 30 34 mV
Current-Limit Threshold
(Negative)
V
NEG
V
CSH
_ - V
CSL
_ , SKIP_ = V
CC
-43 -36 -29 mV
Current-Limit Threshold
(Zero Crossing)
V
ZX
V
CSH
_ - V
CSL
_ , SKIP_ = GND 3 mV
Idle Mode™ Threshold I
MIN
V
CSH
_ - V
CSL
_ , SKIP_ = GND 3.6 6 8.4 mV
REFERENCE (REF)
T
A
= +25°C to +85°C 2.482 2.50 2.518
Reference Voltage V
REF
V
CC
= 4.5V to 5.5V,
I
REF
= 0
T
A
= 0°C to +85°C 2.475 2.50 2.525
V
Refer ence S our ce Load Reg ul ati on ΔV
REF
I
REF
= 0µA to 250µA 0.25 1.5 mV
Reference Sink Load Regulation I
REF
= -50µA 6 mV
REF Lockout Voltage V
R E F
(
U V L O
)
Rising edge, hysteresis = 100mV 2.3 V
CURRENT BALANCE
Current-Balance Amplifier (GMI)
Offset
[V(CSH1,CSL1) - V(CSH2,CSL2)] at I
CCI
= 0 -2 +2 mV
Current-Balance Amplifier (GMI)
Transconductance
ΔI
CCI
/Δ[V(CSH1,CSL1) - V(CSH2,CSL2)],
V
CCI
= V
OUT
= 0.5V to 2.5V, and
V(CSH_,CSL_) = -60.0mV to +60.0mV
200 µS
FAULT DETECTION
OVP_ Adjust Range V
OVP_
0.5 2.5 V
Outp ut Over vol tag e Tr i p Thr eshol d
Rising edge measured at CSL_,
with respect to OVP_ set voltage
180 200 220 mV
Output Overvoltage Fault
Propagation Delay
t
OVP
50mV overdrive 10 µs
Output Undervoltage Protection
Trip Threshold
Falling edge measured at CSL_,
with respect to error comparator threshold
-325 300 -275 mV
Output Undevoltage Fault
Propagation Delay
t
UVP
50mV overdrive 10 µs
Output Undervoltage Protection
Blanking Time
t
BLANK
From rising edge of ON_ 6144 1/f
SW
PGOOD_ Lower Trip Threshold
Falling edge measured at CSL_,
with respect to error comparator threshold,
hysteresis = 1%
-180 -150 -120 mV
PGOOD_ Propagation Delay t
PGOOD
_ Falling edge, 50mV overdrive 10 µs
Idle Mode is a trademark of Maxim Integrated Products, Inc.