kh231 Fairchild Semiconductor, kh231 Datasheet - Page 5

• Manufacturer Part Number: kh231
• Description: Fast Settling, Wideband Buffer/amplifier Av = 1 To 5
• Manufacturer: Fairchild Semiconductor

KH231
Offset Voltage Adjustment
If trimming of the input offset voltage (V
desired, a resistor value of 10kΩ to 1MΩ placed between
pins 8 and 9 will cause V
8mV to 0.2mV respectively. Similarly, a resistor placed
between pins 1 and 2 will cause V
positive.
Thermal Considerations
At high ambient temperatures or large internal power
dissipations, heat sinking is required to maintain
acceptable junction temperatures. Use the thermal
model on the previous page to determine junction
temperatures. Many styles of heat sinks are available for
TO-8 packages; the Thermalloy 2240 and 2268 are good
examples. Some heat sinks are the radial fin type which
cover the pc board and may interfere with external
components. An excellent solution to this problem is to
use surface mounted resistors and capacitors. They
have a very low profile and actually improve high
frequency performance. For use of these heat sinks with
conventional components, a 0.1” high spacer can be inserted
under the TO-8 package to allow sufficient clearance.
P
P
For positive V
device. For negative V
pnp device.
I
back R in R
R
collector and ±V
The limiting factor for output current and voltage is junction
temperature. Of secondary importance is I
should not exceed 150mA.
T
similar for T
T
REV. 1A February 2001
col
j(pnp)
j(cir)
(circuit)
(xxx)
col
= V
is a resistor (33Ω recommended) between the xxx
= P
100°C/W
= [(±V
= P
P
o
T
= (I
/R
pnp
j(pnp)
(cir)
(pnp)
L
CC
j(npn)
L
or 4mA, whichever is greater. (Include feed-
(48 + θ
CC
.)
)((+V
o
) – V
(100 + θ
CC
.
and V
CC
.
100°C/W
ca
out
P
) – (V
T
) + (P
npn
j(npn)
o
– (I
CC
ca
and V
os
, this is the power in the npn
) + (P
CC
col
(pnp)
to become more negative by
)) where I
) (R
CC
(cir)
+ P
col
, this is the power in the
17.5
P
+ P
T
+ 4)] (I
(npn)
circuit
os
j(circuit)
°
C/W
CC
, to become more
(npn)
)(θ
os
= 16mA at ±15V
col
ca
)(θ
= V
) + T
) (%Duty)
(out)
+
ca
-
) + T
ni
T
θ
T
ca
case
ambient
, which
a
-V
.
a
in
,
) is
θ
For example, with the KH231 operating at ±15V while
driving a 100Ω load at 15V
pulse waveform, DC = 0), P
= 33) and P
215 heat sink and air flow of 300 ft/min the output
transistors’ T
the rest of the circuit is 32°C above ambient. In still air,
however, the rise in T
With no heat sink, the rise in T
respectively! Under most conditions, HEAT SINKING IS
REQUIRED.
Other methods of heat sinking may be used, but for
best results, make contact with the base of the KH231
package, use a large thermal capacity heat sink and use
forced air convection.
Low V
The KH231 is designed to operate on supplies as low as
±5V. In order to improve full bandwidth at reduced sup-
ply voltages, the supply current (I
The plot of Bandwidth vs. V
ing pins 1 and 2 and pins 8 and 9; this will increase both
bandwidth and supply current. Care should be taken to
not exceed the maximum junction temperatures; for this
reason this technique should not be used with supplies
exceeding ±10V.
external resistors between pins 1 and 2 and pins 8 and 9
can be used.
ca
= 65°C/W for the KH231 without heat sink in still air.
30°C/W for the KH231 with a Wakefield 215 heat
sink in still air.
10°C/W for the KH231 with a Wakefield 215 heat
sink at 300 ft/min air.
30°C/W for the KH231 with a Thermalloy 2240A
heat sink in still air.
5°C/W for the KH231 with a Thermalloy 2240A
heat sink at 500 ft/min air.
CC
Operation: Supply Current Adjustment
j
is 28°C above ambient and worst case T
(cir)
= 0.48W.
For intermediate values of V
j
is 45°C and 49°C, respectively.
CC
(npn)
pp
, shows the effect of short-
Then with the Wakefield
output (50% duty cycle
= P
CC
j
) must be increased.
(pnp)
is 75°C and 79°C,
= 190mW (R
DATA SHEET
CC
j
col
in
5
,