7

MD2134

Supertex inc.

www.supertex.com

Doc.# DSFP-MD2134

C102412

Serial Port Interface (SPI) Read Write Timing for Control Register

Tx Output Timing Diagram

PA and PB Output Current Equations

LV0

LV1

LV2

LV3

LV4

LV5

LV6

t

r

t

f

t

df

t

dr

90%

10%

90%

10%

90%

10%

90%

10%

t

r

t

f

t

df

t

dr

I(LV5)

I(LV1)

I(LV2)

I(LV3)

I(LV4)

I(LV15)

I(LV9)

I(LV8)

I(LV12)

I(LV13)

I = 0

I = 0

if LV6 = 0

I = 0

I = 0

PA

Current

PA

Current

M3 = 1,

M[2:0]

M3 = 0,

M[2:0]

LV0

LV9

LV8 LV12

LV13 LV15

LV0

1

16

15

3

2

t6

t4

t3

t2

t1

t9

t7

t5

t8

t10

SCK

SDI

CS

SDO

LD

nitudes I

tions.

I

48 • V

6

- 1) •

LAx

127

9 • R

FB

I

48 • V

6

- 1) •

LBx

127

9 • R

FB

Where the V

mal value of the data in the DAC register, R

resistor value in ohms, LAx or LBx is the decimal value of

the data in the level register.

The values of the results from the equations represent the

magnitude of the output current. The current flow into the

port PA or PB is controlled by M0, M1, M2 or M3 are turned

on. Note that the maximum full scale peak current at PA or

PB port only can be obtained at DAC = 255, V

R

PB.