MP2104DJ-1.5 MPS [Monolithic Power Systems], MP2104DJ-1.5 Datasheet - Page 6

• Manufacturer Part Number: MP2104DJ-1.5
• Description: 1.7MHz, 600mA Synchronous Step-Down Converter
• Manufacturer: MPS [Monolithic Power Systems]

PIN FUNCTIONS
OPERATION
The MP2104 is a constant frequency current
mode PWM step-down converter. The MP2104
is optimized for low voltage, Li-Ion battery
powered applications where high efficiency and
small size are critical. The MP2104 uses an
external resistor divider to set the output
voltage from 0.6V to 6V. The device integrates
both a main switch and a synchronous rectifier,
which provides high efficiency and eliminates
MP2104 Rev. 1.3
10/4/2005
EN
FB
Pin # Name Description
IN
1
2
3
4
5
5
FEEDBACK
GND Ground.
OUT
SW
EN
FB
IN
REFERENCE
0.6V
ERROR
VOLTAGE
TM
AMP
BIAS
&
Regulator Enable Control Input. Drive EN above 1.5V to turn on the MP2104. Drive EN below
0.3V to turn it off (shutdown current < 0.1µA).
Power Switch Output. Inductor connection to drains of the internal PFET and NFET switches.
Supply Input. Bypass to GND with a 2.2µF or greater ceramic capacitor.
Feedback Input (MP2104DJ). Connect FB to the center point of the external resistor divider. The
feedback threshold voltage is 0.6V.
Output Voltage Sense Input (MP2104DJ-1.5 and MP2104DJ-1.8). An internal resistor divider is
connected to this pin to set the proper output voltage.
17pF
+
--
EAMP
CC
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
SLOPE COMP
Figure 1—Functional Block Diagram (MP2104)
MP2104 – 1.7MHz 600mA SYNCHRONOUS STEP-DOWN CONVERTER
EAO
ICS
OSCILLATOR
1.7MHz
+
+
--
PWMCMP
© 2005 MPS. All Rights Reserved.
www.MonolithicPower.com
PWM
OSC
CONTROL
LOGIC
PWM
an external Schottky diode. The MP2104 can
achieve 100% duty cycle. The duty cycle D of a
step-down converter is defined as:
Where T
the oscillator frequency (1.7MHz), V
output voltage and V
CURRENT
SENSE
D
AMP
=
ON
DH
DL
T
IAMP
ON
10X
is the main switch on time, f
×
+
--
f
OSC
×
IN
100
is the input voltage.
MAIN
SWITCH
(PCH)
SYNCHRONOUS
RECTIFIER
(NCH)
%
≈
V
V
OUT
IN
×
100
OUT
%
MP2104_BD01
is the
OSC
SW
GND
is
6