Datasheet MAX38889 (Maxim) - 6

MAX38889 2.5V to 5.5V, 3A Reversible Buck/Boost Regulator for Backup Applications
V EFFICIENCY SYS TRANSITION BACKUP DURING BUCK MODE LOAD REGULATION
toc12 toc11 100 toc10 3.5 VSYS = 3.6V, ICHG = 1.5A 3.4 VSYS = 3V 3% REGULATION 90 3.3 VSYS 5V/div ) 3.2 80 %(Y (V) 3.1 C N IE 70 V SYS 3 BKB 5V/div EFFIC 2.9 60 2.8 VCAP=1.5V 50 2.7 VCAP=2.5V VCAP 2V/div 2.6 40 2.5 0 0.5 1 1.5 2 2.5 3 1 10 100 1000 VSYS_TARGET = 3V, VCAP = 2.7V, ISYS = 1.5A VCAP (V) I SYS (mA) 4ms/div
VSYS TRANSITION FROM DISABLE BACKUP BY ENB BACKUP TO CHARGING CHARGE PROFILE
toc14 toc13 toc15 VSYS 2V/div V 5V/div SYS VSYS 1V/div ENB 1V/div BKB 5V/div VCAP 1V/div V 2V/div CAP 2V/div VCAP VSYS_TARGET = 3V to VSYS = 5V, VCAP = 2.7V, ISYS = 1.5A V V 4ms/div SYS_TARGET = 3V, ISYS = 0.3A SYS = 3.6V, VCAP_TARGET = 2.7V 2s/div 2s/div
DISCHARGE PROFILE CHARGE-DISCHARGE PROFILE
toc16 toc17
ISYS MAX vs. VCAP
2500 toc18 3% REGULATION
VSYS = 5V
2000 VSYS A) (m 1500
VSYS = 3V
V V AX SYS 1V/div SYS 1V/div M I SYS 1000 V 500 CAP 1V/div VCAP 1V/div 0 V 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 SYS_TARGET = 3V, VCAP = 2.7V, ISYS = 0.75A VSYS_TARGET = 3V, VCAP = 2.7V, ISYS = 0.9A 2s/div V 4s/div CAP (V) www.maximintegrated.com Maxim Integrated | 6 Document Outline Product Highlights Key Applications Simplified Application Diagram Pin Configuration Absolute Maximum Ratings Package Information Electrical Characteristics Typical Operating Characteristics Pin Configuration Pin Descriptions Functional Diagram Detailed Description Application Circuits Supercapacitor Voltage Configuration System Voltage Configuration Charge/Discharge Current Configuration Charging Backup Applications Information Capacitor Selection Supercapacitor Selection Inductor Selection Status Flags BKB Flag RDY Flag Enabling the Device Charger Enable Input (ENC) Backup Enable Input (ENB) PCB Layout Guidelines Ordering Information