Datasheet
1000 10000 100000 300000
−40
−30
−20
−10
0
10
20
30
40
−120
−90
−60
−30
0
30
60
90
120
Frequency (kHz)
Gain (dB)
Phase (°)
Gain
Phase
G000
1000 10000 100000 300000
−40
−30
−20
−10
0
10
20
30
40
−120
−90
−60
−30
0
30
60
90
120
Frequency (kHz)
Gain (dB)
Phase (°)
Gain
Phase
G000
LMZ34002
SNVS989A –JULY 2013–REVISED SEPT 2013
www.ti.com
TYPICAL CHARACTERISTICS (BODE PLOTS)
(2)
(continued)
Figure 31. V
IN
= 36 V, V
OUT
= –5 V, I
OUT
= 2.0 A, Figure 32. V
IN
= 36 V, V
OUT
= –12 V, I
OUT
= 1.8 A,
C
OUT
= 4 x 22 µF ceramic, f
SW
= 500 kHz C
OUT
= 4 x 22 µF ceramic, f
SW
= 800 kHz
CAPACITOR RECOMMENDATIONS FOR THE LMZ34002 POWER SUPPLY
Capacitor Technologies
Electrolytic, Polymer-Electrolytic Capacitors
When using electrolytic capacitors, high-quality, computer-grade electrolytic capacitors are recommended.
Polymer-electrolytic type capacitors are recommended for applications where the ambient operating temperature
is less than 0°C. The Sanyo OS-CON capacitor series is suggested due to the lower ESR, higher rated surge,
power dissipation, ripple current capability, and small package size. Aluminum electrolytic capacitors provide
adequate decoupling over the frequency range of 2 kHz to 150 kHz, and are suitable when ambient temperatures
are above 0°C.
Ceramic Capacitors
The performance of aluminum electrolytic capacitors is less effective than ceramic capacitors above 150 kHz.
Multilayer ceramic capacitors have a low ESR and a resonant frequency higher than the bandwidth of the
regulator. They can be used to reduce the reflected ripple current at the input as well as improve the transient
response of the output.
Tantalum, Polymer-Tantalum Capacitors
Polymer-tantalum type capacitors are recommended for applications where the ambient operating temperature is
less than 0°C. The Sanyo POSCAP series and Kemet T530 capacitor series are recommended rather than many
other tantalum types due to their lower ESR, higher rated surge, power dissipation, ripple current capability, and
small package size. Tantalum capacitors that have no stated ESR or surge current rating are not recommended
for power applications.
Input Capacitor
The LMZ34002 requires a minimum input capacitance of 4.7 μF of ceramic type. The voltage rating of input
capacitors must be greater than the maximum input voltage. The ripple current rating of the capacitor must be at
least 450 mArms. Table 1 includes a preferred list of capacitors by vendor.
Output Capacitor
The required output capacitance of the LMZ34002 can be comprised of either all ceramic capacitors, or a
combination of ceramic and bulk capacitors. The required output capacitance must include at least 2 × 47 µF of
ceramic type (or 4 × 22 µF). The voltage rating of output capacitors must be greater than the output voltage.
When adding additional non-ceramic bulk capacitors, low-ESR devices like the ones recommended in Table 1
are required. Additional capacitance above the required minimum is determined by actual transient deviation
requirements. Table 1 includes a preferred list of capacitors by vendor.
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