LMZ12003DEMO/NOPB National Semiconductor, LMZ12003DEMO/NOPB Datasheet - Page 3

• Manufacturer Part Number: LMZ12003DEMO/NOPB
• Description: BOARD DEV PWR MODULE LMZ12003
• Manufacturer: National Semiconductor
• Series: SIMPLE SWITCHER®r

Specifications of LMZ12003DEMO/NOPB

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.8V
• Current - Output: 3A
• Voltage - Input: 4.5 ~ 20 V
• Regulator Topology: Buck
• Frequency - Switching: Up to 1MHz
• Board Type: Fully Populated
• Utilized Ic / Part: LMZ12003
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -
• Other names: LMZ12003DEMO

Demo Board Bill of Materials
Demo Board Hookup
VOUT Connect the load to VOUT and one of the GND posts.
The module can source up to a 3A load current.
Connect Vin to a positive voltage in the 4.5 to 20V range.
Connect the negative terminal of the source supply to one of
the posts labeled GND.
The Enable input post is configured for direct connection to
the Vin post. With the chosen resistor values this results in an
under voltage lockout level of 4.5V input. The top enable re-
sistor is RENT (aka REN1) and the bottom enable resistor is
RENB (aka REN2).
If the Enable post is disconnected, the module will be disabled
and about 20 uA of supply current will flow from Vin to ground
while in the disabled mode. With the enable input connected
to Vin via the resistor divider there will be about 1.5 mA of no-
Ref Des
Ron
Rent
Renb
Rfbt
Rfbb
Cff
Css
Cin
Cout1
Cout2
U1
Alternate resistor values for alternative output voltages
VOUT
6
5
3.3
2.5
1.8
1.5
1.2
0.8
Description
32.4 kohm 1%
resistor
32.4 kohm 1%
resistor
11.8 kohm 1%
resistor
1.87 kohm 1%
resistor
1.50 kohm 1%
resistor
0.022 uF 50V X7R
ceramic capacitor
0.022 uF 50V X7R
ceramic capacitor
10 uF 50V X5R
ceramic capacitor
1.0 uF 50V X7R
ceramic capacitor
100 uF 6.3V X5R
ceramic capacitor
LMZ12003
SIMPLE
SWITCHER
Power Module
RFBT
2.49k
5.62k
3.32k
2.26k
1.87k
1.00k
4.22k
0.0K
3
Case
603
603
603
603
603
603
603
1210
1206
1210
TO-PMOD
RFBB
383 ohm
1.07k
1.07k
1.07k
1.50k
1.13k
8.45k
39.2k
load quiescent current into the Vin input. Additional current
flows into the enable divider string.
Demo Board Passive Components
Soft-start capacitor The soft-start capacitor controls the rise
time of the output voltage when power is first applied and fol-
lowing the clearing of a fault mode.
Feedback divider Regulator output voltage is programmed
though the selection of the two resistors. RFBT ( aka RFB1)
and RFB (aka RFB2) A feed forward capacitor (CFF) is lo-
cated in parallel with the upper feedback divider resistor. This
capacitor improves the step response to abrupt changes in
load current. Refer to the table above when modifying the
board for a different output voltage. Resistor values shown
will minimize error in output voltage setting.
RON Resistor: The primary function of the RON resistor is to
set the On-Time interval of the internal control section switch-
Manufacturer
Part Number
UMK325BJ106M
M-T
UMK316B7105KL
-T
JMK325BJ107M
M-T
LMZ12003TZ-
ADJ
RON
124k
100k
61.9k
47.5k
32.4k
28.0k
22.6k
24.9k
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