MPQ2169B

– 6V, DUAL 1.4A/1.4A OR 2A/0.8A SYNC BUCK REGULATOR, AEC-Q100

MPQ2169B Rev. 1.0

MonolithicPower.com

19

12/20/2021

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1.0

1.5

2.0

2.5

3.0

3.5

50

70

90

110

130

150

RFREQ (kΩ)

fSW vs. RFREQ

0.2

0.4

0.6

0.8

1.0

1.2

1.4

150

250

350

450

550

650

RFREQ (kΩ)

fSW vs. RFREQ (continued)

Figure 4: fSW vs. RFREQ

Table 1 shows the fSW and RFREQ values.

Table 1: fSW vs. RFREQ

RFREQ

(

kΩ)

fSW

(kHz)

RFREQ

(

kΩ)

fSW

(kHz)

665

350

90

2000

499

460

84.5

2100

200

1000

78.7

2200

169

1200

75

2300

130

1500

51

3000

The internal fSW can also be synchronized to an

external clock applied at the SYNC pin. The

rising

edge

of

the

channel

1

clock

is

synchronized to the external clock

’s rising edge,

while the channel 2 clock remains 180° out-of-

phase from channel 1. The recommended

external SYNC frequency range is 350kHz to

3MHz.

While

there

is

no

pulse

width

requirement, note that there is always parasitic

capacitance on the pad. If the pulse width is too

short, a clear rising and falling edge may not be

seen. It is recommended to make the pulse

longer than 100ns.

Power Good (PG)

The MPQ2169B has one power good (PG)

output to indicate normal operation after SS.

PG is the open drain of an internal MOSFET. It

should be connected to VIN, VCC, or an

external voltage source through a resistor (e.g.

100k

Ω). After VIN is applied, the MOSFET turns

on and PG is pulled to GND before SS is ready.

After the FB voltage (VFB) reaches 90% of the

reference voltage (VREF), the MOSFET turns off

and PG is pulled high by an external voltage

source. If VFB drops to 82% of VREF, the PG

voltage is pulled to GND to indicate an output

failure.

Current Limit and Short Circuit

Each channel of the MPQ2169B has a typical

4A current limit for the HS-FET. Once the

inductor current (IL) reaches the current limit,

the HS-FET turns off immediately. Then the

low-side

MOSFET

(LS-FET)

turns

on

to

discharge the energy, and IL decreases. The

HS-FET does not turn on again until IL drops

below a specified current threshold (called the

valley current limit). This protection prevents IL

from

running

away

and

damaging

the

components.

If VFB drops below 60% of VREF and SS has

finished, the MPQ2169B treats this as a short

fault and attempts to recover with hiccup mode.

In hiccup mode, the MPQ2169B disables the

output power stage, slowly discharges CSS, and

soft starts automatically. If the short-circuit

condition still remains, the MPQ2169B repeats

this operation cycle until the short circuit is

removed and the output rises back to regulation

levels.