MAX750ACSA Maxim Integrated Products, MAX750ACSA Datasheet - Page 8

• Manufacturer Part Number: MAX750ACSA
• Description: IC REG PWM STEP-DWN ADJ 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of MAX750ACSA

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.25 ~ 11 V
• Current - Output: 450mA
• Frequency - Switching: 170kHz
• Voltage - Input: 4 ~ 11 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Voltage - Supply: 4 V ~ 11 V
• Frequency-max: 210kHz
• Duty Cycle: 92%
• Pwm Type: Current Mode
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

The overcurrent comparator triggers when the load cur-
rent exceeds approximately 1.5A. On each clock
cycle, the output FET turns on and attempts to deliver
current until cycle-by-cycle or overcurrent limits are
exceeded. Note that the soft-start capacitor must be
greater than 0.01µF for overcurrent protection to func-
tion properly. A typical value is 0.1µF. A soft-start
cycle is initiated when the overcurrent comparator is
triggered.
The undervoltage lockout feature monitors the supply
voltage at V+ and allows operation to start when V+
rises above 3.75V. When V+ falls, operation continues
until the supply voltage falls below 3.50V. When an
Adjustable, Step-Down,
Current-Mode PWM Regulators
Figure 1. Detailed Block Diagram with External Components
8
*
_______________________________________________________________________________________
SEE TABLE 3 FOR COMPONENT VALUES AND SUPPLIERS.
330pF
R1
510K
C1
0.1µF
0.01µF
C5
C6
REF
R2
R3
CC
SS
±35%
1M
BANDGAP
1.23V
MAX750A
MAX758A
Undervoltage Lockout
Overcurrent Limiting
BIAS
GEN
SHDN
ERROR
AMP
SS CLAMP
COMPARATOR
SLOPE COMPENSATION
PWM
GND
R
RAMP
OSC
GEN
F/F
S
OVERCURRENT COMPARATOR
Q
undervoltage condition is detected, control logic turns
off the output power FET and discharges the soft-start
capacitor to ground. This prevents partial turn-on of
the power MOSFET and avoids excessive power dissi-
pation. The control logic holds the output power FET
off until the supply voltage rises above approximately
3.75V, at which time a soft-start cycle begins.
The MAX750A/MAX758A are shut down by keeping
SHDN at ground. In shutdown mode, the output power
FET is held off and the output drops to 0V. The internal
reference also turns off, which causes the soft-start
capacitor to discharge. The 6µA typical standby cur-
rent includes external-component leakage currents. As
temperature increases past +85°C, the external capaci-
SENSE AMP
CURRENT
UNDERVOLTAGE
LOCKOUT
R SENSE
V UVLO
V+
V
IN
Shutdown Mode
LX
C2
1µF
D1
1N5817
L1
C3
*
C4
*
V
OUT