Relation between slew rate and gain-bandwidth product?

G

Gundal21

Guest
Hi~

I've posted the following text to the sci.electronics.design group.
But
it seems so fundamental to post to the group, so I post it again here.

-------------------------------------------------------------------------------------------------------
Hi~

Can someone tell me the relation between slew rate and gain-bandwidth
product?
Though the relation is not direct, I've been thought that the more the
slew rate is
the higher the gain-bandwidth product is. But I found that the MP103
from Apex(now Cirrus) has 167V/usec slew rate and 250kHz gain-
bandwidth product and the MP111 has 130 V/usec and 6MHz gain-bandwidth
product. Is there any relationship between these
two properties? I've been thought that the high gain-bandwidth product
means high speed,
so it also means high slew rate. It will be helpful to tell me any
kinds of materials on this.

Thanks.
 
"Gundal21" <hocheol.lee@gmail.com> wrote in message
news:096d71ac-44c7-4c08-92e3-1ceab05e9707@m3g2000pri.googlegroups.com...
Hi~

I've posted the following text to the sci.electronics.design group.
But
it seems so fundamental to post to the group, so I post it again here.

--------------------------------------------------------------------------
-----------------------------
Hi~

Can someone tell me the relation between slew rate and gain-bandwidth
product?
Though the relation is not direct, I've been thought that the more the
slew rate is
the higher the gain-bandwidth product is. But I found that the MP103
from Apex(now Cirrus) has 167V/usec slew rate and 250kHz gain-
bandwidth product and the MP111 has 130 V/usec and 6MHz gain-bandwidth
product. Is there any relationship between these
two properties? I've been thought that the high gain-bandwidth product
means high speed,
so it also means high slew rate. It will be helpful to tell me any
kinds of materials on this.

Thanks.
Click to expand...
Slew rate related to the actual voltage and maximum frequency at that
voltage and only losely to the GBWP. Given a sine wave of frequency wt, the
voltage, V = Vp*sinwt. The slew rate is the first derivitive of the voltage:
dV/dt = Vp*w*coswt. w is omega = 2*pi*f, and the maximum value of the cosine
= 1.

Therefore the slew rate, p = dV/dt = Vp*2*pi*f

Example: if the peak voltage, Vp = 10 volts, the frequency = 1 MHz, p =
2*10*pi*10^6 = 62.8*10^6 volts per second or 62.8 volts per microsecond.

The slew rate of amplifiers and other circuits is determinded by the current
available to charge and discharge the capacitances in the circuit. dv =
(1/C)int *i *dt. In most amplifiers, there is a dominant capacitace usually
used for compensation that the available current must charge and discharge.
That usually defines the slews rate as well as the GBWP. But the relation is
not simple because the available voltage must be taken into account.
 
Gundal21 wrote in message
<096d71ac-44c7-4c08-92e3-1ceab05e9707@m3g2000pri.googlegroups.com>...
Hi~

I've posted the following text to the sci.electronics.design group.
But
it seems so fundamental to post to the group, so I post it again here.

---------------------------------------------------------------------------
----------------------------
Hi~

Can someone tell me the relation between slew rate and gain-bandwidth
product?
Though the relation is not direct, I've been thought that the more the
slew rate is
the higher the gain-bandwidth product is. But I found that the MP103
from Apex(now Cirrus) has 167V/usec slew rate and 250kHz gain-
bandwidth product and the MP111 has 130 V/usec and 6MHz gain-bandwidth
product. Is there any relationship between these
two properties? I've been thought that the high gain-bandwidth product
means high speed,
so it also means high slew rate. It will be helpful to tell me any
kinds of materials on this.

Thanks.
Click to expand...
If it helps -
Bw = .35 x rise time
 
JeffM wrote in message
<99d552d3-a531-4fbe-ba7f-6132842096ea@p36g2000vbn.googlegroups.com>...
bg wrote:
If it helps -
Bw = .35 x rise time

Only if you reciprocate something.
Click to expand...

good catch, thx
make that bw = .35 x 1/t
bg
 
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