Rainbow Electronics MAX799 - Manual (Page 3)

MAX796/MAX797/MAX799
Step-Down Controllers with
Synchronous Rectifier for CPU Power
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Note 1: Since the reference uses VL as its supply, V+ line-regulation error is insignificant.
Note 2: At very low input voltages, quiescent supply current may increase due to excess PNP base current in the VL linear
regulator. This occurs only if V+ falls below the preset VL regulation point (5V nominal). See the Quiescent Supply Current
vs. Supply Voltage graph in the
Typical Operating Characteristics .
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 15V, GND = PGND = 0V, IVL = IREF = 0A, T A = 0°C to +70°C for MAX79_C, T A = 0°C to +85°C for MAX79_E,
T A = -55°C to +125°C for MAX79_M, unless otherwise noted.)
SECFB, 0V or 4V
SHDN, 0V or 30V
SHDN, SKIP
SYNC
SYNC = 0V or 5V
No external load (Note 1)
SYNC = REF
Guaranteed by design
CSH = CSL = 6V
V+ = 4V, CSL = 0V (Note 2)
SYNC = 0V or 5V
SHDN = 0V, V+ = 30V,
CSL = 0V or 6V
Falling edge
0µA < I REF < 100µA
SYNC = REF
SHDN = 0V, CSL = 6V, V+ = 0V or 30V, VL = 0V
CONDITIONS
0.1
MAX79_C
µA
2.0
MAX79_E/M
Input Current
2.0
V
VL - 0.5
Input High Voltage
%
93 96
89 91
Maximum Duty Cycle
kHz 190 340 Oscillator Sync Range
ns 200 SYNC Rise/Fall Time
ns 200 SYNC Low Pulse Width
ns 200 SYNC High Pulse Width
125 150 175
kHz
270 300 330
Oscillator Frequency
2.45 2.55
V
2.46 2.505 2.54
Reference Output Voltage
mW 4.8 6.6 Quiescent Power Consumption
mW 4 8 Dropout Power Consumption
1 5
µA
1 3
V+ Shutdown Current
V 1.8 2.3 Reference Fault Lockout Voltage
mV 50 Reference Load Regulation
µA 0.1 1 CSL Shutdown Leakage Current
UNITS MIN TYP MAX PARAMETER
MAX79_C
MAX79_E/M
MAX79_C
MAX79_E/M
FB = CSH = CSL = 6V,
VL switched over to CSL
1 5
µA
1 3
V+ Off-State Leakage Current
DL forced to 2V
FB, FB = REF
CSH, CSL, CSH = CSL = 6V, device not shut down
SYNC, SKIP
A 1 DL Sink/Source Current
±100
50
1.0
SHDN, SKIP
SYNC
0.5
V
0.8
Input Low Voltage
DH forced to 2V, BST-LX = 4.5V A 1 DH Sink/Source Current
High or low, BST-LX = 4.5V
High or low
Ω
7 DH On-Resistance
Ω
7 DL On-Resistance
OSCILLATOR AND INPUTS/OUTPUTS
nA