MAX1836ETT50+T Maxim Integrated Products, MAX1836ETT50+T Datasheet - Page 7

• Manufacturer Part Number: MAX1836ETT50+T
• Description: IC DC-DC CONV 5V 6-TDFN
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX1836ETT50+T

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 4.8 ~ 5.2 V
• Current - Output: 125mA
• Voltage - Input: 4.5 ~ 24 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 6-TDFN Exposed Pad
• Power - Output: 1.95W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

The MAX1836/MAX1837 step-down converters are
designed primarily for battery-powered devices, note-
book computers, and industrial control applications. A
unique current-limited control scheme provides high
efficiency over a wide load range. Operation up to
100% duty cycle allows the lowest possible dropout
voltage, increasing the useable supply voltage range.
Under no-load, the MAX1836/MAX1837 draw only
12µA, and in shutdown mode, they draw only 3µA to
further reduce power consumption and extend battery
life. Additionally, an internal 24V switching MOSFET,
Figure 1. Typical MAX1836 Application Circuit
PIN
—
1
2
3
4
5
6
C
L1 = SUMIDA CDRH5D28-470
C
D1 = NIHON EP05Q03L
NOTE: HIGH-CURRENT PATHS SHOWN WITH BOLD LINES.
10µF
INPUT
4.5V OR 12V
25V
IN
OUT
C
IN
= TAIYO YUDEN TMK432BJ106KM
= SANYO POSCAP 6TPC100M (SMALLER CAPACITORS CAN BE USED FOR 5V)
NAME
SHDN
GND
OUT
FB
LX
EP
IN
IN
GND
SHDN
_______________________________________________________________________________________
Dual-Mode Feedback Input. Connect to GND for the preset 3.3V (MAX183_EUT33) or 5.0V (MAX183_EUT50)
output. Connect to a resistive divider between the output and FB to adjust the output voltage between 1.25V
and V
SHDN to IN.
Ground
Input Voltage. 4.5V to 24V input range. Connected to the internal p-channel power MOSFET’s source.
Inductor Connection. Connected to the internal p-channel power MOSFET’s drain.
Shutdown Input. A logic low shuts down the MAX1836/MAX1837 and reduces supply current to 3µA. LX is
high impedance in shutdown. Connect to IN for normal operation. When setting output voltages above 5.5V,
permanently connect SHDN to IN.
Regulated Output Voltage High-Impedance Sense Input. Internally connected to a resistive divider. Connect
to the output when using the preset output voltage. Connect to GND when using an external resistive divider
to adjust the output voltage.
Exposed Metal Pad. Connect to GND. This pad is internally connected to GND through a soft connect. For
proper grounding and good thermal dissipation, connect the exposed pad to GND.
MAX1836
24V Internal Switch, 100% Duty Cycle,
Detailed Description
IN
, and connect the OUT pin to GND. When setting output voltages above 5.5V, permanently connect
OUT
LX
FB
D1
47µH
L1
3.3V OR 5V
OUTPUT
C
100µF
6.3V
OUT
internal current sensing, and a high switching frequen-
cy minimize PC board space and component cost.
The MAX1836/MAX1837 use a proprietary current-limit-
ed control scheme that operates with duty cycles up to
100%. These DC-DC converters pulse as needed to
maintain regulation, resulting in a variable switching fre-
quency that increases with the load. This eliminates the
high supply currents associated with conventional con-
stant-frequency pulse-width-modulation (PWM) con-
trollers that switch the MOSFET unnecessarily.
Figure 2. Typical MAX1837 Application Circuit
Step-Down Converters
FUNCTION
10µF
C
L1 = SUMIDA CDRH5D28-220
C
D1 = NIHON ED05Q03L
NOTE: HIGH-CURRENT PATHS SHOWN WITH BOLD LINES.
INPUT
4.5V OR 12V
25V
IN
OUT
C
IN
= TAIYO YUDEN TMK432BJ106KM
= SANYO OS-CON 6SA150M (SMALLER CAPACITORS CAN BE USED FOR 5V)
Current-Limited Control Architecture
IN
SHDN
GND
MAX1837
OUT
LX
FB
Pin Description
D1
22µH
L1
3.3V OR 5V
OUTPUT
C
150µF
6.3V
OUT
7