MAX77720 datasheet(39/52 Pages) AD

39 / 52 page

Wide Output-Voltage Range, Dual-

Polarity PMIC

MAX77720

www.analog.com

Analog Devices | 39

10. The controller issues an ACKNOWLEDGE (ACK) signaling the target that it wishes to receive more data.

11. Step 9 to step 10 are repeated as many times as the controller requires. Following the last byte of data, the controller

must issue a NOT ACKNOWLEDGE (NACK) to signal that it wishes to stop receiving data.

12. The controller sends a STOP condition (P) or a REPEATED START condition (Sr). Issuing a STOP condition (P)

ensures that the bus input filters are set for 1MHz or slower operation. Issuing a REPEATED START condition (Sr) leaves

the bus input filters in their current state.

DATA X + 3

R/W

TARGET ADDRESS

ACK

1 1

Sr TARGET ADDRESS

DATA X

ACK

NUMBER

OF BITS

R/W

ACK

NUMBER

OF BITS

DATA X + 2

DATA X + 1

ACK

DATA N

NACK

DATA N - 1

ACK

DATA N - 2

ACK

LEGEND

NUMBER

OF BITS

P OR

Sr*

*P FORCES THE BUS FILTERS TO SWITCH TO THEIR 1MHz MODE. SR LEAVES THE

BUS FILTERS IN THEIR CURRENT STATE.

TARGET TO

CONTROLLER

CONTROLLER TO

TARGET

ACK

Figure 21. Reading from Sequential Registers

Applications Information

Inverting Buck-Boost and Boost Enable Options

The MAX77720 offers a high degree of control flexibility. The EN pin can be used to enable both the boost and inverting

buck-boost

with

its

respective

programmed

delays

(CNFG_DLY0.STRTUP_DLY_BST

and

CNFG_DLY1_STRTUP_DLY_IBB). The boost converter can be forced on with no delay by I2C by setting

CNFG_GLBL.FRC_BST_ON = 1. Similarly, the inverting buck-boost converter can also be forced on with no delay through

I2C by setting CNFG_GLBL.FRC_IBB_ON = 1.

Input-Capacitor Selection

Input capacitors reduce current peaks drawn from the battery or input power source and reduce switching noise in the

system. Ceramic capacitors with X5R or X7R dielectric are highly recommended due to their small size, low, ESR, and

small temperature coefficients. Other capacitor types can be used as well, but at a tradeoff of higher ESR.

It is recommended to have a minimum 12μF effective capacitance between the INIBB pin and PGND and a minimum

12μF effective capacitance between the boost inductor and PGND. Both of these capacitors should be placed as close

to the IC as possible.

Additionally, it is recommended to have a 1μF bypass capacitor between the IN pin and AGND. This is to ensure stable

operation of the MAX77720 and to reduce any noise injections that might affect the performance of the IC.

To fully utilize the available input-voltage range of the device (5.5V max), use a input capacitor voltage rating of at least

6.3V).

Inverting Buck-Boost Inductor Selection

The MAX77720 inverting buck-boost converter is optimized for a 3.3μH inductor.

Choose an inductor with a saturation current that is greater than or equal to the maximum peak current limit setting

(IIBB_ILIM).

Consider the DC resistance (DCR), AC resistance (ACR), and package size of the inductor. Typically, smaller sized

inductors have larger DCR and ACR, which reduce efficiency. Refer to the manufacturer data sheet to balance the trade-

offs between DCR, ACR (i.e., core losses), variation with temperature, and component cost.

MAX77720 Datasheet(PDF) 39 Page - Analog Devices

MAX77720 Datasheet(HTML) 39 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Datasheet Download

Link URL