User Manual

MAX1775
Dual-Output Step-Down
DC-DC Converter for PDA/Palmtop Computers
4 _______________________________________________________________________________________
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
LOGIC INPUTS
SHDNM, SHDNC Input Low
Voltage
0.4 V
SHDNM, SHDNC Input High
Voltage
2.0 V
SHDNM, SHDNC Input Low
Current
SHDNM = SHDNC = GND -1 1 µA
SHDNC Input High Current V
SHDNC
= +5.5V 5 µA
V
SHDNM
= +5V 2
SHDNM Input High Current
V
SHDNM
= +28V 15 30
µA
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= +12V, V
MAIN
= V
INC
= V
CS-
= V
CS+
= +3.3V, V
CORE
= +1.8V, Circuit of Figure 4, T
A
= 0°C to +85°C, unless otherwise noted.
Typical values are at T
A
= +25°C.)
ELECTRICAL CHARACTERISTICS
(V
IN
= +12V, V
MAIN
= V
INC
= V
CS-
= V
CS+
= +3.3V, V
CORE
= +1.8V, Circuit of Figure 4, T
A
-40°C to +85°C, unless otherwise noted.)
(Note 2)
PARAMETER SYMBOL CONDITIONS MIN MAX UNITS
Input Voltage V
IN
2.7 28 V
Input Quiescent Supply Current I
IN
V
FBM
= +1.5V, V
FBC
= +1.5V,
V
SHDNM
= V
SHDNC
= +3.3V
30 µA
CS- Quiescent Supply Current I
CS-
V
FBM
= +1.5V, V
FBC
= +1.5V,
V
SHDNM
= V
SHDNC
= +3.3V
220 µA
Core Regulator Quiescent
Supply Current
I
INC
V
FBM
= +1.5V, V
FBC
= +1.5V,
V
SHDNM
= V
SHDNC
= +3.3V
120 µA
IN Shutdown Supply Current SHDNM = SHDNC = GND 30 µA
MAIN REGULATOR
Main Output Voltage Adjust
Range
1.25 5.5 V
FBM Regulation Threshold V
FBM
V
(
C S + - C S -
)
= 0 to + 60m V , V
I N
= + 2.7V to + 28V 1.21 1.29 V
FBM Input Current I
FBM
V
FBM
= +1.3V -0.1 0.1 µA
Current-Limit Threshold V
CL
V
CS+
- V
CS-
60 100 mV
M i ni m um C ur r ent- Li m i t Thr eshol d V
CS+
- V
CS-
624mV
Valley Current Threshold V
CS+
- V
CS-
40 60 mV
Zero Current Threshold V
CS+
- V
CS-
015mV
PDRV, NDRV Gate Drive
Resistance
V
CS-
= +3.3V 4.4 Ω
CS- to CVL Switch Resistance I
CVL
= 50mA 8 Ω