Data Sheet

LT7200S

analog.com

Rev 0

21 of 35

of the TRACK pin. When TRACK is above 0.5V, tracking is disabled, and the feedback voltage regulates to the internal

reference voltage.

For output tracking applications, when driving TRACK pin from another voltage source, set each channel’s output to

either coincidentally or ratiometrically track another supply’s output, as shown in Figure 34. In the following

discussions, VOUT1 refers to output of channel 1 as a master channel, and VOUT2, VOUT3, and VOUT4 refer to outputs of

channels 2, 3, and 4 respectively. In practice, use either channel as the master.

(a) Coincident Tracking

(b) Ratiometric Tracking

Figure 34. Output Tracking Applications

To implement the coincident tracking in Figure 34(a), connect additional resistive dividers to VOUT1 and connect its

midpoint to the TRACK pins of the slave channels. The ratio of these dividers should be the same as those of the slave

channels’ feedback dividers shown in Figure 35(a). In this tracking mode, VOUT1 must be set higher than VOUT2, VOUT3,

and VOUT4.

To implement the ratiometric tracking, the feedback pin of the master channel should connect to the TRACK pins of

the slave channels shown in Figure 35(b).

(a) Coincident Tracking

TIME

VOUT1

VOUT3

VOUT4

VOUT2

TIME

VOUT1

VOUT3

VOUT4

VOUT2

VFB4

R7

VOUT3

VOUT4

VOUT1

R1

R3

R5

R7

VOUT2

R3

R8

R2

R4

R6

R8

R4

R6

R5

TO

TRACK4

VFB1

TO

TRACK2

TO

TRACK3

VFB2

VFB3