ADP1879(RevA) Ver la hoja de datos (PDF) - Analog Devices

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ADP1879
(Rev.:RevA)

Synchronous Buck Controller with Constant On Time and Valley Current Mode

Analog Devices 

ADP1878/ADP1879

Data Sheet

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

ADP1878/ADP1879

VIN 1

COMP 2

EN 3

FB 4

GND 5

RES 6

VREG 7

14 BST

13 SW

12 DRVH

11 PGND

10 DRVL

9 PGOOD

8 SS

TOP VIEW

(Not to Scale)

NOTES

1. CONNECT THE EXPOSED PAD TO THE

ANALOG GROUND PIN (GND).

Figure 3. Pin Configuration

Table 4. Pin Function Descriptions

Pin

No. Mnemonic Description

1

VIN

High-Side Input Voltage. Connect VIN to the drain of the high-side MOSFET.

2

COMP

Output of the Error Amplifier. Connect compensation network between this pin and AGND to achieve stability (see

the Compensation Network section).

3

EN

IC Enable. Connect EN to VREG to enable the IC. When pulled down to AGND externally, EN disables the IC.

4

FB

Noninverting Input of the Internal Error Amplifier. This is the node where the feedback resistor is connected.

5

GND

Analog Ground Reference Pin of the IC. Connect all sensitive analog components to this ground plane (see the Layout

Considerations section).

6

RES

Current Sense Gain Resistor (External). Connect a resistor between the RES pin and GND (Pin 5).

7

VREG

Internal Regulator Supply Bias Voltage for the ADP1878/ADP1879 Controller (Includes the Output Gate Drivers).

Connecting a bypass capacitor of 1 μF directly from this pin to PGND and a 0.1 μF capacitor across VREG and GND are

recommended.

8

SS

Soft Start Input. Connect an external capacitor to GND to program the soft start period. There is a capacitance value

of 10 nF for every 1 ms of soft start delay.

9

PGOOD

Open-Drain Power-Good Output. PGOOD sinks current when FB is out of regulation or during thermal shutdown.

Connect a 3 kΩ resistor between PGOOD and VREG. Leave PGOOD unconnected if it is not used.

10 DRVL

Drive Output for the External Low-Side, N-Channel MOSFET. This pin also serves as the current sense gain setting pin

(see Figure 69).

11 PGND

Power Ground. Ground for the low-side gate driver and low-side N-channel MOSFET.

12 DRVH

Drive Output for the External High-Side N-Channel MOSFET.

13 SW

Switch Node Connection.

14 BST

Bootstrap for the High-Side N-Channel MOSFET Gate Drive Circuitry. An internal boot rectifier (diode) is connected

between VREG and BST. A capacitor from BST to SW is required. An external Schottky diode can also be connected

between VREG and BST for increased gate drive capability.

EP

Exposed Pad. Connect the exposed pad to the analog ground pin (GND).

Rev. A | Page 6 of 40

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