MAX1927REUB Maxim Integrated Products, MAX1927REUB Datasheet - Page 7

• Manufacturer Part Number: MAX1927REUB
• Description: DC/DC Switching Converters 800mA PWM Step-Down DC/DC Converter
• Manufacturer: Maxim Integrated Products

Figure 1. Simplified Functional Diagram
PIN
10
1
2
3
4
5
6
7
8
9
Low-Output-Voltage, 800mA, PWM Step-Down
NAME
COMP
PGND
SHDN
BATT
PWM
GND
POK
REF
FB
LX
_______________________________________________________________________________________
Forced-PWM Input. Drive to GND to use PWM at medium to heavy loads and pulse-skipping at light loads.
Drive to BATT to force PWM operation at all loads.
Output Feedback Sense Input. To set the output voltage to the preset voltage (MAX1928), connect FB directly
to the output. To adjust the output voltage (MAX1927R), connect FB to the center of an external resistor-
divider between the output and GND. FB regulation voltage is 0.75V.
Compensation Input. See the Compensation, Stability, and Output Capacitor section for compensation
component selection.
Shutdown Control Input. Drive low to shut down the converter. Drive high for normal operation.
Power Ground
Inductor Connection to the drains of the internal power MOSFETs.
Supply Voltage Input. Connect to a 2.6V to 5.5V source. Bypass to GND with a low-ESR 10µF capacitor.
Power-OK Open-Drain Output. Once the soft-start routine has completed, POK goes high impedance 20ms
after FB exceeds 90% of its expected final value.
Ground
Internal 1.25V Reference. Bypass to GND with a 0.1µF capacitor.
COMP
SHDN
PWM
REF
COMP
TO
1MHz
COMPENSATION
OSC
REFERENCE
CONTROL
1.25V
PWM
SLOPE
MAX1927
MAX1928
COMPARATOR
GND
MAX1927R
ONLY
PWM
N-CHANNEL
CURRENT COMPARATOR
ILIM
COMPARATOR
PFM CURRENT
COMPARATOR
FUNCTION
BATT
BIAS
N
POWER-OK
CONTROL
MAX1928
ONLY
P
DC-DC Converters
P
N
LX
PGND
POK
FB
Pin Description
7