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PRELIMINARY
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MicroRAM
Rev. 1.1
Page 5 of 8
μRAM2xxx
Ripple Attenuation @ 28V (Room Temp.)
-80.00
-60.00
-40.00
-20.00
0.00
20.00
10
100
1,000
10,000
Freq. (Hz)
100,000
1,000,000
10,000,000
G
10A, 100uF Vref
10A, No Vref Cap
Ripple Attenuation @ 5V (Room Temp.)
-80.00
-60.00
-40.00
-20.00
0.00
20.00
10
100
1,000
10,000
Freq. (Hz)
100,000
1,000,000
10,000,000
G
10A, 100uF Vref
10A, No Vref Cap
Figure 3a, 3b
—Curves demonstrating the small signal attenuation performance as measured on a network analyzer with a typical
module at (a) 28V and 10A output and (b) 5V and 10A. The low frequency attenuation can be enhanced by connecting a 100μF
capacitor, C
, to the V
REF
pin as shown in Figures 1 and 2.
Figure 4a-4b
—Simulated graphs demonstrating the tradeoff of attenuation versus headroom setting at 20 Amps and an equivalent
100°C baseplate temperature at 3V and 28V.
Figure 4c-4d
—MicroRam attenuation vs. power dissipation at 3V 20A, and 28V 20A.
Frequency
10Hz
100Hz
1.0KHz
10KHz
100KHz
1.0MHz
...
DB(V(VOUT))
-75
-50
-25
-0
Vout=3V Iload=20A
100 degrees baseplate temperature
Rhr=28k (Vheadroom=90mV)
27k (100mV)
26k (110mV)
22k (160mV)
2423k (150mV)
25k (122mV)
1817k (260mV)
19k (217mV)
2120k (197mV)
Frequency
10Hz
100Hz
1.0KHz
10KHz
100KHz
1.0MHz
...
DB(V(VOUT))
-75
-50
-25
-0
Rhr=260k (Vheadroom=90mV)
250k (100mV)
240k (110mV)
230k (122mV)
220k (135mV)
210k (150mV)
200k (160mV)
190k (180mV)
180k (197mV)
170k (217mV)
160k (240mV)
150k (260mV)
Vout=28V Iload=20A
100 degrees baseplate temperature
17k
18k
19k
20k
21k
22k
23k
24k
25k
26k
27k
Rhr=28k
-70
-60
-50
-40
-30
-20
-10
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Watts
500khz 3V
1Mhz 3V
100khz 3V
d
28V 20A
Rhr=260k
250k
240k
230k
220k
210k
200k
190k
180k
170k
160k
150k
-70
-60
-50
-40
-30
-20
-10
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Watts
d
100khz 28V
500khz 28V
1Mhz 28V
Notes:
The measurements in Figures 8-16 were taken with a μRAM2C21 and standard scope probes with a 20MHz bandwidth scope setting. The criteria for transient current
capability was as follows: The transient load current step was incremented from 10A to the peak value indicated, then stepped back to 10A until the resulting output peak to
peak was around 40mV.