LMZ23605TZ National Semiconductor, LMZ23605TZ Datasheet - Page 18

• Manufacturer Part Number: LMZ23605TZ
• Description: POWER MODULE, 36V, 5A, 7TO-PMOD
• Manufacturer: National Semiconductor

Specifications of LMZ23605TZ

• Primary Input Voltage: 36V
• No. Of Outputs: 1
• Output Voltage: 6V
• Output Current: 5A
• Voltage Regulator Case Style: TO-PMOD
• No. Of Pins: 7
• Operating Temperature Range: -40°C To +125°C
• Rohs Compliant: Yes

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going high. Trace two is 1.5V pre-bias rising to 3.3V. Risetime
determined by C
DISCONTINUOUS CONDUCTION AND CONTINUOUS
CONDUCTION MODES
At light load the regulator will operate in discontinuous con-
duction mode (DCM). With load currents above the critical
conduction point, it will operate in continuous conduction
mode (CCM). In CCM, current flows through the inductor
through the entire switching cycle and never falls to zero dur-
ing the off-time. When operating in DCM, inductor current is
maintained to an average value equaling Iout. Inductor cur-
rent exhibits normal behavior for the emulated current mode
control method used. Output voltage ripple typically increases
during this mode of operation.
Following is a comparison pair of waveforms of the showing
both CCM (upper) and DCM operating modes.
SS
, trace three.
Pre-Biased Startup
30116925
18
The approximate formula for determining the DCM/CCM
boundary is as follows:
I
The inductor internal to the module is 3.3 μH. This value was
chosen as a good balance between low and high input voltage
applications. The main parameter affected by the inductor is
the amplitude of the inductor ripple current (I
calculated with:
I
Where V
812 kHz.
If the output current I
I
DCB
LR P-P
L
, the higher and lower peak of I
≊
V
=V
V
O
IN
*(V
O
IN
*(V
= 12V, V
is the maximum input voltage and f
IN
CCM and DCM Operating Modes
–V
IN
- V
O
)/(2*3.3 μH*f
O
)/(3.3µH*f
O
= 3.3V, I
O
is determined by assuming that I
SW
SW(CCM)
O
*V
= 3A/0.3A 2 μsec/div
LR
IN
) (14)
can be determined.
*V
IN
) (13)
30116912
LR
SW
). I
is typically
LR
can be
O
=