TPS51216

SLUSAB9A – NOVEMBER 2010 – REVISED APRIL 2013

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Power State Control

The TPS51216 has two input pins, S3 and S5, to provide simple control scheme of power state. All of VDDQ,

VTTREF and VTT are turned on at S0 state (S3=S5=high). In S3 state (S3=low, S5=high), VDDQ and VTTREF

voltages are kept on while VTT is turned off and left at high impedance state (high-Z). The VTT output floats and

does not sink or source current in this state. In S4/S5 states (S3=S5=low), all of the three outputs are turned off

and discharged to GND according to the discharge mode selected by MODE pin. Each state code represents as

follow; S0 = full ON, S3 = suspend to RAM (STR), S4 = suspend to disk (STD), S5 = soft OFF. (See Table 1)

Table 1. S3/S5 Power State Control

STATE

S3

S5

VREF

VDDQ

VTTREF

VTT

S0

HI

HI

ON

ON

ON

ON

S3

LO

HI

ON

ON

ON

OFF(High-Z)

S4/S5

LO

LO

OFF

OFF(Discharge)

OFF(Discharge)

OFF(Discharge)

MODE Pin Configuration

The TPS51216 reads the MODE pin voltage when the S5 signal is raised high and stores the status in a register.

A 15-

μA current is sourced from the MODE pin during this time to read the voltage across the resistor connected

between the pin and GND. Table 2 shows resistor values, corresponding switching frequency and discharge

mode configurations.

Table 2. MODE Selection

RESISTANCE BETWEEN

SWITCHING

MODE NO.

DISCHARGE MODE

MODE AND GND ( k

Ω)

FREQUENCY (kHz)

3

200

400

Tracking

2

100

300

1

68

300

Non-tracking

0

47

400

Discharge Control

In S4/S5 state, VDDQ, VTT, and VTTREF outputs are discharged based on the respective discharge mode

selected above. The tracking discharge mode discharges VDDQ output through the internal VTT regulator

transistors enabling quick discharge operation. The VTT output maintains tracking of the VTTREF voltage in this

mode. (Please refer to Figure 25) After 4 ms of tracking discharge operation, the mode changes to non-tracking

discharge. The VDDQ output must be connected to the VLDOIN pin in this mode. The non-tracking mode

discharges the VDDQ and VTT pins using internal MOSFETs that are connected to corresponding output

terminals. The non-tracking discharge is slow compared with the tracking discharge due to the lower current

capability of these MOSFETs. (Please refer to Figure 26)

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