Rainbow Electronics MAX8737 - Manual (Page 7)

MAX8737
Dual, Low-Voltage Linear Regulator Controllers
with External MOSFETs
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MAX8737
Dual, Low-Voltage Linear Regulator Controllers
with External MOSFETs
Pin Description
PIN NAME FUNCTION
1 V CC
Analog and Driver Supply Input. Connect to the system supply voltage (+5.0V). Bypass V CC to analog
ground with a 1µF or greater ceramic capacitor.
2 CS1
Positive Current-Sense Input for LDO1. To enable (foldback) current limit, connect CS1 to the positive
terminal of the current-sense element as shown in Figure 1. The MAX8737 driver reduces the gate
voltage when the 10mV (typ) current-limit threshold is exceeded. When CS1 is connected to V
CC , the
MAX8737 disables the current-limit protection and enables the output undervoltage protection (see the
UVP Short-Circuit Protection section).
3 OUT1
Outp ut Feed b ack- S ense, N eg ati ve C ur r ent- S ense, and D i schar g e Inp ut for LD O 1. C onnect d i r ectl y to the
l i near r eg ul ator outp ut. W hen LD O1 i s d i sab l ed , OU T1 i s d i schar g ed thr oug h an i nter nal 10
Ω FE T to GN D .
4 REFIN1 External Reference Input for LDO1. REFIN1 sets the main output regulation voltage (V OUT1 = V REFIN1 ).
5 PGOOD2
Open-Drain Power-Good Output for LDO2. PGOOD2 is low when the output voltage is more than 12%
(typ) below the normal regulation point, during soft-start, and in shutdown. Approximately 2ms (typ) after
OUT2 reaches the regulation voltage (REFIN2), PGOOD2 becomes high impedance as long as the
output remains in regulation.
6 PGOOD1
Open-Drain Power-Good Output for LDO1. PGOOD1 is low when the output voltage is more than 12%
(typ) below the normal regulation point, during soft-start, and in shutdown. Approximately 2ms (typ) after
OUT1 reaches the regulation voltage (REFIN1), PGOOD1 becomes high impedance as long as the
output remains in regulation.
7 EN2
Enable Input for LDO2. Connect EN2 to Vcc for always ON. When EN2 is pulled low, the linear regulator
shuts down and pulls the output to ground.
8 EN1
Enable Input for LDO1. Connect EN1 to Vcc for always ON. When EN1 is pulled low, the linear regulator
shuts down and pulls the output to ground.
9 REFIN2
External Reference Input for the Secondary Regulator (LDO2). REFIN2 sets the main output regulation
voltage (V
OUT2
= V
REFIN2
).
10 OUT2
Output Sense, Negative Current-Sense Input, and Discharge Input for the Secondary Regulator (LDO2).
Connect directly to the linear regulator output. When the LDO2 is disabled, OUT2 is discharged through
an internal 10
Ω FET to GND.
11 CS2
Positive Current-Sense Input for LDO2. To enable (foldback) current limit, connect CS2 to the positive
terminal of the current-sense element as shown in Figure 1. The MAX8737 driver reduces the gate
voltage when the 10mV (typ) current-limit threshold is exceeded. When CS2 is connected to V
CC , the
MAX8737 disables the current-limit protection and enables the output undervoltage protection (see the
UVP Short-Circuit Protection section).
12, 14 N.C. Not Internally Connected
13 DRV2 External N-Channel Gate Drive for LDO2
15 GND Ground. Connect the thin QFN backside pad to GND.
16 DRV1 External N-Channel Gate Drive for LDO1
— EP Exposed Pad. Connect the thin QFN backside pad to GND.