M68060 USER’S MANUAL
126.96.36.199.1 Linear Voltage Regulator Solution.
This solution uses a linear voltage regula-
tor to supply 2 A at 3.3 V. This solution is inexpensive; however, conversion efficiency of only
up to 65% can be achieved. Figure 11-1 shows a solution using power BJTs. This solution
would be used primarily for applications that are cost sensitive, but not power sensitive. The
suggested linear solution meets the 3.3 V
5% MC68060 specifications.
188.8.131.52.2 Switching Regulator Solution.
This solution uses switching regulators. Linear
Technologies offers two parts, the LTC1147 and LTC1148 and MAXIM offers the MAX767.
The main difference among these parts is a trade-off between price, part count, and conver-
The LTC1147 solution is less expensive and has one fewer MOSFET than the LTC1148
solution. The LTC1148 is less than $5 in 1000 piece quantities, and the LTC1147 is less
than $4 in 1000 piece quantities. In either of these solutions there are around 15 discrete
Figure 11-1. Linear Voltage Regulator Solution
CL 3.3 V
D2 D3 D4
T1 = TIP32
T2 = 2N2222A
D1 = TL431CLP
D2,D3,D4 = IN4001
R1 = 220
R2,R3,R4 = 1K
R5 = 2.2K
C1 = 47
C2 = 0.01
C3 = 0.033
CL = 47